1
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Zhang J, Jiao M, Lu Z, Lu H, Wang M, Shi Z. Hydrodeuteroalkylation of Unactivated Olefins Using Thianthrenium Salts. Angew Chem Int Ed Engl 2024; 63:e202409862. [PMID: 38866703 DOI: 10.1002/anie.202409862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 06/10/2024] [Accepted: 06/12/2024] [Indexed: 06/14/2024]
Abstract
Isotopically labeled alkanes play a crucial role in organic and pharmaceutical chemistry. While some deuterated methylating agents are readily available, the limited accessibility of other deuteroalkyl reagents has hindered the synthesis of corresponding products. In this study, we introduce a nickel-catalyzed system that facilitates the synthesis of various deuterium-labeled alkanes through the hydrodeuteroalkylation of d2-labeled alkyl TT salts with unactivated alkenes. Diverging from traditional deuterated alkyl reagents, alkyl thianthrenium (TT) salts can effectively and selectively introduce deuterium at α position of alkyl chains using D2O as the deuterium source via a single-step pH-dependent hydrogen isotope exchange (HIE). Our method allows for high deuterium incorporation, and offers precise control over the site of deuterium insertion within an alkyl chain. This technique proves to be invaluable for the synthesis of various deuterium-labeled compounds, especially those of pharmaceutical relevance.
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Affiliation(s)
- Jie Zhang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Mengjie Jiao
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Zheng Lu
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
- Jiangsu Nata Opto-electronic Material Co., Ltd., Suzhou, 215126, China
| | - Hongjian Lu
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Minyan Wang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
| | - Zhuangzhi Shi
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210093, China
- School of Chemistry and Materials Science, Nanjing Normal University, 210023, Nanjing, China
- School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan, 453007, China
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2
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Fu W, Fu Y, Zhao Y, Wang H, Liu P, Yang Y. A metalloenzyme platform for catalytic asymmetric radical dearomatization. Nat Chem 2024:10.1038/s41557-024-01608-8. [PMID: 39198700 DOI: 10.1038/s41557-024-01608-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 07/17/2024] [Indexed: 09/01/2024]
Abstract
Catalytic asymmetric dearomatization represents a powerful means to convert flat aromatic compounds into stereochemically well-defined three-dimensional molecular scaffolds. Using new-to-nature metalloredox biocatalysis, we describe an enzymatic strategy for catalytic asymmetric dearomatization via a challenging radical mechanism that has eluded small-molecule catalysts. Enabled by directed evolution, new-to-nature radical dearomatases P450rad1-P450rad5 facilitated asymmetric dearomatization of a broad spectrum of aromatic substrates, including indoles, pyrroles and phenols, allowing both enantioconvergent and enantiodivergent radical dearomatization reactions to be accomplished with excellent enzymatic control. Computational studies revealed the importance of additional hydrogen bonding interactions between the engineered metalloenzyme and the reactive intermediate in enhancing enzymatic activity and enantiocontrol. Furthermore, designer non-ionic surfactants were found to significantly accelerate this biotransformation, providing an alternative means to promote otherwise sluggish new-to-nature biotransformations. Together, this evolvable metalloenzyme platform opens up new avenues to advance challenging catalytic asymmetric dearomatization processes involving free radical intermediates.
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Affiliation(s)
- Wenzhen Fu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Yue Fu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Yunlong Zhao
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Huanan Wang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA.
- Biomolecular Science and Engineering (BMSE) Program, University of California, Santa Barbara, CA, USA.
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3
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Wang TC, Zhang Z, Rao G, Li J, Shirah J, Britt RD, Zhu Q, Yang Y. Threonine Aldolase-Catalyzed Enantioselective α-Alkylation of Amino Acids through Unconventional Photoinduced Radical Initiation. J Am Chem Soc 2024; 146:22476-22484. [PMID: 38961805 PMCID: PMC11376206 DOI: 10.1021/jacs.4c05949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
Visible light-driven pyridoxal radical biocatalysis has emerged as a promising strategy for the stereoselective synthesis of valuable noncanonical amino acids (ncAAs). Previously, the use of well-tailored photoredox catalysts represented the key to enable efficient pyridoxal phosphate (PLP) enzyme-catalyzed radical reactions. Here, we report a PLP-dependent threonine aldolase-catalyzed asymmetric α-C-H alkylation of abundant amino acids using Katritzky pyridinium salts as alkylating agents. The use of engineered threonine aldolases allowed for this redox-neutral radical alkylation to proceed efficiently, giving rise to challenging α-trisubstituted and -tetrasubstituted ncAA products in a protecting-group-free fashion with excellent enantiocontrol. Mechanistically, this enantioselective α-alkylation capitalizes on the unique reactivity of the persistent enzymatic quinonoid intermediate derived from the PLP cofactor and the amino acid substrate to allow for novel radical C-C coupling. Surprisingly, this photobiocatalytic process does not require the use of well-established photoredox catalysts and operates through an unconventional photoinduced radical generation involving a PLP-derived aldimine. The ability to develop photobiocatalytic reactions without relying on classic photocatalysts or photoenzymes opens up new avenues for advancing stereoselective intermolecular radical reactions that are not known in either organic chemistry or enzymology.
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Affiliation(s)
- Tian-Ci Wang
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Zheng Zhang
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Guodong Rao
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Jiedong Li
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Josephine Shirah
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - R David Britt
- Department of Chemistry, University of California Davis, Davis, California 95616, United States
| | - Qilei Zhu
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, United States
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
- Biomolecular Science and Engineering Program, University of California Santa Barbara, Santa Barbara, California 93106, United States
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4
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Ju S, Li D, Mai BK, Liu X, Vallota-Eastman A, Wu J, Valentine DL, Liu P, Yang Y. Stereodivergent photobiocatalytic radical cyclization through the repurposing and directed evolution of fatty acid photodecarboxylases. Nat Chem 2024; 16:1339-1347. [PMID: 38632367 PMCID: PMC11321912 DOI: 10.1038/s41557-024-01494-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 02/28/2024] [Indexed: 04/19/2024]
Abstract
Despite their intriguing photophysical and photochemical activities, naturally occurring photoenzymes have not yet been repurposed for new-to-nature activities. Here we engineered fatty acid photodecarboxylases to catalyse unnatural photoredox radical C-C bond formation by leveraging the strongly oxidizing excited-state flavoquinone cofactor. Through genome mining, rational engineering and directed evolution, we developed a panel of radical photocyclases to facilitate decarboxylative radical cyclization with excellent chemo-, enantio- and diastereoselectivities. Our high-throughput experimental workflow allowed for the directed evolution of fatty acid photodecarboxylases. An orthogonal set of radical photocyclases was engineered to access all four possible stereoisomers of the stereochemical dyad, affording fully diastereo- and enantiodivergent biotransformations in asymmetric radical biocatalysis. Molecular dynamics simulations show that our evolved radical photocyclases allow near-attack conformations to be easily accessed, enabling chemoselective radical cyclization. The development of stereoselective radical photocyclases provides unnatural C-C-bond-forming activities in natural photoenzyme families, which can be used to tame the stereochemistry of free-radical-mediated reactions.
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Affiliation(s)
- Shuyun Ju
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Dian Li
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Binh Khanh Mai
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Xin Liu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - Alec Vallota-Eastman
- Interdepartmental Graduate Program for Marine Science, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Jianping Wu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA
| | - David L Valentine
- Marine Science Institute, University of California Santa Barbara, Santa Barbara, CA, USA
- Department of Earth Science, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, USA.
- Biomolecular Science and Engineering (BMSE) Program, University of California Santa Barbara, Santa Barbara, CA, USA.
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5
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Jain S, Ospina F, Hammer SC. A New Age of Biocatalysis Enabled by Generic Activation Modes. JACS AU 2024; 4:2068-2080. [PMID: 38938808 PMCID: PMC11200230 DOI: 10.1021/jacsau.4c00247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/17/2024] [Accepted: 04/19/2024] [Indexed: 06/29/2024]
Abstract
Biocatalysis is currently undergoing a profound transformation. The field moves from relying on nature's chemical logic to a discipline that exploits generic activation modes, allowing for novel biocatalytic reactions and, in many instances, entirely new chemistry. Generic activation modes enable a wide range of reaction types and played a pivotal role in advancing the fields of organo- and photocatalysis. This perspective aims to summarize the principal activation modes harnessed in enzymes to develop new biocatalysts. Although extensively researched in the past, the highlighted activation modes, when applied within enzyme active sites, facilitate chemical transformations that have largely eluded efficient and selective catalysis. This advance is attributed to multiple tunable interactions in the substrate binding pocket that precisely control competing reaction pathways and transition states. We will highlight cases of new synthetic methodologies achieved by engineered enzymes and will provide insights into potential future developments in this rapidly evolving field.
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Affiliation(s)
| | | | - Stephan C. Hammer
- Research Group for Organic Chemistry
and Biocatalysis, Faculty of Chemistry, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
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6
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Xia T, Wu W, Wu X, Qu J, Chen Y. Cobalt-Catalyzed Enantioselective Reductive α-Chloro-Carbonyl Addition of Ketimine to Construct the β-Tertiary Amino Acid Analogues. Angew Chem Int Ed Engl 2024; 63:e202318991. [PMID: 38252658 DOI: 10.1002/anie.202318991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 01/21/2024] [Accepted: 01/22/2024] [Indexed: 01/24/2024]
Abstract
β-Tertiary amino acid derivatives constitute one of the most frequently occurring units in natural products and bioactive molecules. However, the efficient asymmetric synthesis of this motif still remains a significant challenge. Herein, we disclose a cobalt-catalyzed enantioselective reductive addition reaction of ketimine using α-chloro carbonyl compound as a radical precursor, providing expedient access to a diverse array of enantioenriched β-quaternary amino acid analogues. This protocol exhibits outstanding enantioselectivity and broad substrate scope with excellent functional group tolerance. Preliminary mechanism studies rule out the possibility of Reformatsky-type addition and confirm the involvement of radical species in stereoselective addition process. The synthetic utility has been demonstrated through the rapid assembly of iterative amino acid units and oligopeptide, showcasing its versatile platform for late-stage modification of drug candidates.
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Affiliation(s)
- Tingting Xia
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Wenwen Wu
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Xianqing Wu
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Jingping Qu
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
| | - Yifeng Chen
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering, Feringa Nobel Prize Scientist Joint Research Center, Frontiers Science Center for Materiobiology and Dynamic Chemistry, School of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, China
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7
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Tang L, Shen C, Hao S, Dong K. A Type of Chiral C 2-Symmetric Arylthiol Catalyst for Highly Enantioselective Anti-Markovnikov Hydroamination. J Am Chem Soc 2024; 146:16248-16256. [PMID: 38808533 DOI: 10.1021/jacs.4c04596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
The development of chiral hydrogen donor catalysts is fundamental in the expansion and innovation of asymmetric organocatalyzed reactions via an enantioselective hydrogen atom transfer (HAT) process. Herein, an unprecedented type of chiral C2-symmetric arylthiol catalysts derived from readily available enantiomeric lactate ester was developed. With these catalysts, an asymmetric anti-Markovnikov alkene hydroamination-cyclization reaction was established, affording a variety of pharmaceutically interesting 3-substituted piperidines with moderate to high enantioselectivity. Results of the designed control experiments and theoretical computation rationalized the origin of stereocontrol and disclosed the spatial effect of the moiety of chiral thiols on the enantioselectivity. We believed the facile synthesis, flexible tunability, and effective enantioselectivity-controlling capability of these catalysts would shed light on the development of versatile chiral HAT catalysts and related asymmetric reactions.
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Affiliation(s)
- Lin Tang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, State Key Laboratory of Petroleum Molecular & Process Engineering, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Chaoren Shen
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, State Key Laboratory of Petroleum Molecular & Process Engineering, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Shaoyu Hao
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, State Key Laboratory of Petroleum Molecular & Process Engineering, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Kaiwu Dong
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, State Key Laboratory of Petroleum Molecular & Process Engineering, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
- Chang-Kung Chuang Institute, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
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8
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Chen B, Li R, Feng J, Zhao B, Zhang J, Yu J, Xu Y, Xing Z, Zhao Y, Wang B, Huang X. Modular Access to Chiral Amines via Imine Reductase-Based Photoenzymatic Catalysis. J Am Chem Soc 2024; 146:14278-14286. [PMID: 38727720 DOI: 10.1021/jacs.4c03879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
Abstract
The development of catalysts serves as the cornerstone of innovation in synthesis, as exemplified by the recent discovery of photoenzymes. However, the repertoire of naturally occurring enzymes repurposed by direct light excitation to catalyze new-to-nature photobiotransformations is currently limited to flavoproteins and keto-reductases. Herein, we shed light on imine reductases (IREDs) that catalyze the remote C(sp3)-C(sp3) bond formation, providing a previously elusive radical hydroalkylation of enamides for accessing chiral amines (45 examples with up to 99% enantiomeric excess). Beyond their natural function in catalyzing two-electron reductive amination reactions, upon direct visible-light excitation or in synergy with a synthetic photoredox catalyst, IREDs are repurposed to tune the non-natural photoinduced single-electron radical processes. By conducting wet mechanistic experiments and computational simulations, we unravel how engineered IREDs direct radical intermediates toward the productive and enantioselective pathway. This work represents a promising paradigm for harnessing nature's catalysts for new-to-nature asymmetric transformations that remain challenging through traditional chemocatalytic methods.
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Affiliation(s)
- Bin Chen
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Renjie Li
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jianqiang Feng
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Beibei Zhao
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jiawei Zhang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Jinhai Yu
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yuanyuan Xu
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Zhongqiu Xing
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Yue Zhao
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Binju Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Xiaoqiang Huang
- State Key Laboratory of Coordination Chemistry, Chemistry and Biomedicine Innovation Center (ChemBIC), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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9
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Fu H, Hyster TK. From Ground-State to Excited-State Activation Modes: Flavin-Dependent "Ene"-Reductases Catalyzed Non-natural Radical Reactions. Acc Chem Res 2024; 57:1446-1457. [PMID: 38603772 DOI: 10.1021/acs.accounts.4c00129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
Enzymes are desired catalysts for chemical synthesis, because they can be engineered to provide unparalleled levels of efficiency and selectivity. Yet, despite the astonishing array of reactions catalyzed by natural enzymes, many reactivity patterns found in small molecule catalysts have no counterpart in the living world. With a detailed understanding of the mechanisms utilized by small molecule catalysts, we can identify existing enzymes with the potential to catalyze reactions that are currently unknown in nature. Over the past eight years, our group has demonstrated that flavin-dependent "ene"-reductases (EREDs) can catalyze various radical-mediated reactions with unparalleled levels of selectivity, solving long-standing challenges in asymmetric synthesis.This Account presents our development of EREDs as general catalysts for asymmetric radical reactions. While we have developed multiple mechanisms for generating radicals within protein active sites, this account will focus on examples where flavin mononucleotide hydroquinone (FMNhq) serves as an electron transfer radical initiator. While our initial mechanistic hypotheses were rooted in electron-transfer-based radical initiation mechanisms commonly used by synthetic organic chemists, we ultimately uncovered emergent mechanisms of radical initiation that are unique to the protein active site. We will begin by covering intramolecular reactions and discussing how the protein activates the substrate for reduction by altering the redox-potential of alkyl halides and templating the charge transfer complex between the substrate and flavin-cofactor. Protein engineering has been used to modify the fundamental photophysics of these reactions, highlighting the opportunity to tune these systems further by using directed evolution. This section highlights the range of coupling partners and radical termination mechanisms available to intramolecular reactions.The next section will focus on intermolecular reactions and the role of enzyme-templated ternary charge transfer complexes among the cofactor, alkyl halide, and coupling partner in gating electron transfer to ensure that it only occurs when both substrates are bound within the protein active site. We will highlight the synthetic applications available to this activation mode, including olefin hydroalkylation, carbohydroxylation, arene functionalization, and nitronate alkylation. This section also discusses how the protein can favor mechanistic steps that are elusive in solution for the asymmetric reductive coupling of alkyl halides and nitroalkanes. We are aware of several recent EREDs-catalyzed photoenzymatic transformations from other groups. We will discuss results from these papers in the context of understanding the nuances of radical initiation with various substrates.These biocatalytic asymmetric radical reactions often complement the state-of-the-art small-molecule-catalyzed reactions, making EREDs a valuable addition to a chemist's synthetic toolbox. Moreover, the underlying principles studied with these systems are potentially operative with other cofactor-dependent proteins, opening the door to different types of enzyme-catalyzed radical reactions. We anticipate that this Account will serve as a guide and inspire broad interest in repurposing existing enzymes to access new transformations.
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Affiliation(s)
- Haigen Fu
- NHC Key Laboratory of Biotechnology for Microbial Drugs, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Todd K Hyster
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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10
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Wang TC, Mai BK, Zhang Z, Bo Z, Li J, Liu P, Yang Y. Stereoselective amino acid synthesis by photobiocatalytic oxidative coupling. Nature 2024; 629:98-104. [PMID: 38693411 PMCID: PMC11299865 DOI: 10.1038/s41586-024-07284-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 03/07/2024] [Indexed: 05/03/2024]
Abstract
Photobiocatalysis-where light is used to expand the reactivity of an enzyme-has recently emerged as a powerful strategy to develop chemistries that are new to nature. These systems have shown potential in asymmetric radical reactions that have long eluded small-molecule catalysts1. So far, unnatural photobiocatalytic reactions are limited to overall reductive and redox-neutral processes2-9. Here we report photobiocatalytic asymmetric sp3-sp3 oxidative cross-coupling between organoboron reagents and amino acids. This reaction requires the cooperative use of engineered pyridoxal biocatalysts, photoredox catalysts and an oxidizing agent. We repurpose a family of pyridoxal-5'-phosphate-dependent enzymes, threonine aldolases10-12, for the α-C-H functionalization of glycine and α-branched amino acid substrates by a radical mechanism, giving rise to a range of α-tri- and tetrasubstituted non-canonical amino acids 13-15 possessing up to two contiguous stereocentres. Directed evolution of pyridoxal radical enzymes allowed primary and secondary radical precursors, including benzyl, allyl and alkylboron reagents, to be coupled in an enantio- and diastereocontrolled fashion. Cooperative photoredox-pyridoxal biocatalysis provides a platform for sp3-sp3 oxidative coupling16, permitting the stereoselective, intermolecular free-radical transformations that are unknown to chemistry or biology.
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Affiliation(s)
- Tian-Ci Wang
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Binh Khanh Mai
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zheng Zhang
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Zhiyu Bo
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Jiedong Li
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, CA, USA.
- Biomolecular Science and Engineering (BMSE) Program, University of California Santa Barbara, Santa Barbara, CA, USA.
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11
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Thorpe T, Marshall JR, Turner NJ. Multifunctional Biocatalysts for Organic Synthesis. J Am Chem Soc 2024; 146:7876-7884. [PMID: 38489244 PMCID: PMC10979396 DOI: 10.1021/jacs.3c09542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 03/17/2024]
Abstract
Biocatalysis is becoming an indispensable tool in organic synthesis due to high enzymatic catalytic efficiency as well as exquisite chemo- and stereoselectivity. Some biocatalysts display great promiscuity including a broad substrate scope as well as the ability to catalyze more than one type of transformation. These promiscuous activities have been applied individually to efficiently access numerous valuable target molecules. However, systems in which enzymes possessing multiple different catalytic activities are applied in the synthesis are less well developed. Such multifunctional biocatalysts (MFBs) would simplify chemical synthesis by reducing the number of operational steps and enzyme count, as well as simplifying the sequence space that needs to be engineered to develop an efficient biocatalyst. In this Perspective, we highlight recently reported MFBs focusing on their synthetic utility and mechanism. We also offer insight into their origin as well as comment on potential strategies for their discovery and engineering.
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Affiliation(s)
- Thomas
W. Thorpe
- Department
of Chemistry, University of Manchester,
Manchester Institute of Biotechnology, 131 Princess Street, Manchester, United Kingdom, M1
7DN
| | - James R. Marshall
- Department
of Chemistry, University of Manchester,
Manchester Institute of Biotechnology, 131 Princess Street, Manchester, United Kingdom, M1
7DN
| | - Nicholas J. Turner
- Department
of Chemistry, University of Manchester,
Manchester Institute of Biotechnology, 131 Princess Street, Manchester, United Kingdom, M1
7DN
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12
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Liu Y, Bender SG, Sorigue D, Diaz DJ, Ellington AD, Mann G, Allmendinger S, Hyster TK. Asymmetric Synthesis of α-Chloroamides via Photoenzymatic Hydroalkylation of Olefins. J Am Chem Soc 2024; 146:7191-7197. [PMID: 38442365 DOI: 10.1021/jacs.4c00927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024]
Abstract
Photoenzymatic intermolecular hydroalkylations of olefins are highly enantioselective for chiral centers formed during radical termination but poorly selective for centers set in the C-C bond-forming event. Here, we report the evolution of a flavin-dependent "ene"-reductase to catalyze the coupling of α,α-dichloroamides with alkenes to afford α-chloroamides in good yield with excellent chemo- and stereoselectivity. These products can serve as linchpins in the synthesis of pharmaceutically valuable motifs. Mechanistic studies indicate that radical formation occurs by exciting a charge-transfer complex templated by the protein. Precise control over the orientation of molecules within the charge-transfer complex potentially accounts for the observed stereoselectivity. The work expands the types of motifs that can be prepared using photoenzymatic catalysis.
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Affiliation(s)
- Yi Liu
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Sophie G Bender
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Damien Sorigue
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Aix-Marseille University, CEA, CNRS, Institute of Biosciences and Biotechnologies, BIAM Cadarache, 13108 Saint-Paul-lez-Durance, France
| | - Daniel J Diaz
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
- Institute for Foundations of Machine Learning, University of Texas at Austin, Austin, Texas 78712, United States
| | - Andrew D Ellington
- Department of Molecular Bioscience, University of Texas at Austin, Austin, Texas 78712, United States
| | - Greg Mann
- Novartis Pharm. AG, Basel 4002, Switzerland
| | | | - Todd K Hyster
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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13
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Petchey MR, Ye Y, Spelling V, Finnigan JD, Gittings S, Johansson MJ, Hayes MA, Hyster TK. Regiodivergent Radical Termination for Intermolecular Biocatalytic C-C Bond Formation. J Am Chem Soc 2024; 146:5005-5010. [PMID: 38329236 PMCID: PMC10885151 DOI: 10.1021/jacs.4c00482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 01/24/2024] [Accepted: 01/24/2024] [Indexed: 02/09/2024]
Abstract
Radical hydrofunctionalizations of electronically unbiased dienes are challenging to render regioselective, because the products are nearly identical in energy. Here, we report two engineered FMN-dependent "ene"-reductases (EREDs) that catalyze regiodivergent hydroalkylations of cyclic and linear dienes. While previous studies focused exclusively on the stereoselectivity of alkene hydroalkylation, this work highlights that EREDs can control the regioselectivity of hydrogen atom transfer, providing a method for selectively preparing constitutional isomers that would be challenging to prepare using traditional synthetic methods. Engineering the ERED from Gluconabacter sp. (GluER) furnished a variant that favors the γ,δ-unsaturated ketone, while an engineered variant from a commercial ERED panel favors the δ,ε-unsaturated ketone. The effect of beneficial mutations has been investigated using substrate docking studies and the mechanism probed by isotope labeling experiments. A variety of α-bromo ketones can be coupled with cyclic and linear dienes. These interesting building blocks can also be further modified to generate difficult-to-access heterocyclic compounds.
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Affiliation(s)
- Mark R. Petchey
- Compound
Synthesis and Management, Discovery Sciences,
BioPharma R&D, AstraZeneca,
Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - Yuxuan Ye
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca 14850, New York, United States
| | - Victor Spelling
- Early
Chemical Development, Pharmaceutical Sciences, BioPharma R&D, AstraZeneca,
Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - James D. Finnigan
- Prozomix
Ltd., Building 4, West
End Industrial Estate, Haltwhistle NE49 9HA, U.K.
| | - Samantha Gittings
- Prozomix
Ltd., Building 4, West
End Industrial Estate, Haltwhistle NE49 9HA, U.K.
| | - Magnus J. Johansson
- Medicinal
Chemistry, Research and Early Development, Cardiovascular, Renal and
Metabolism (CVRM), BioPharma R&D, AstraZeneca, Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - Martin A. Hayes
- Compound
Synthesis and Management, Discovery Sciences,
BioPharma R&D, AstraZeneca,
Pepparedsleden 1, 431 83 Mölndal, Sweden
| | - Todd K. Hyster
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca 14850, New York, United States
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14
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Reed JH, Seebeck FP. Reagent Engineering for Group Transfer Biocatalysis. Angew Chem Int Ed Engl 2024; 63:e202311159. [PMID: 37688533 DOI: 10.1002/anie.202311159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 09/11/2023]
Abstract
Biocatalysis has become a major driver in the innovation of preparative chemistry. Enzyme discovery, engineering and computational design have matured to reliable strategies in the development of biocatalytic processes. By comparison, substrate engineering has received much less attention. In this Minireview, we highlight the idea that the design of synthetic reagents may be an equally fruitful and complementary approach to develop novel enzyme-catalysed group transfer chemistry. This Minireview discusses key examples from the literature that illustrate how synthetic substrates can be devised to improve the efficiency, scalability and sustainability, as well as the scope of such reactions. We also provide an opinion as to how this concept might be further developed in the future, aspiring to replicate the evolutionary success story of natural group transfer reagents, such as adenosine triphosphate (ATP) and S-adenosyl methionine (SAM).
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Affiliation(s)
- John H Reed
- Department of Chemistry, University of Basel, Mattenstrasse 24a, 4002, Basel, Switzerland
- Molecular Systems Engineering, National Competence Center in Research, 4058, Basel, Switzerland
| | - Florian P Seebeck
- Department of Chemistry, University of Basel, Mattenstrasse 24a, 4002, Basel, Switzerland
- Molecular Systems Engineering, National Competence Center in Research, 4058, Basel, Switzerland
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15
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Li M, Harrison W, Zhang Z, Yuan Y, Zhao H. Remote stereocontrol with azaarenes via enzymatic hydrogen atom transfer. Nat Chem 2024; 16:277-284. [PMID: 37973942 DOI: 10.1038/s41557-023-01368-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 10/13/2023] [Indexed: 11/19/2023]
Abstract
Strategies for achieving asymmetric catalysis with azaarenes have traditionally fallen short of accomplishing remote stereocontrol, which would greatly enhance accessibility to distinct azaarenes with remote chiral centres. The primary obstacle to achieving superior enantioselectivity for remote stereocontrol has been the inherent rigidity of the azaarene ring structure. Here we introduce an ene-reductase system capable of modulating the enantioselectivity of remote carbon-centred radicals on azaarenes through a mechanism of chiral hydrogen atom transfer. This photoenzymatic process effectively directs prochiral radical centres located more than six chemical bonds, or over 6 Å, from the nitrogen atom in azaarenes, thereby enabling the production of a broad array of azaarenes possessing a remote γ-stereocentre. Results from our integrated computational and experimental investigations underscore that the hydrogen bonding and steric effects of key amino acid residues are important for achieving such high stereoselectivities.
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Affiliation(s)
- Maolin Li
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Wesley Harrison
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Zhengyi Zhang
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Yujie Yuan
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Huimin Zhao
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Carl Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- NSF Molecular Maker Lab Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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16
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Shi Q, Kang XW, Liu Z, Sakthivel P, Aman H, Chang R, Yan X, Pang Y, Dai S, Ding B, Ye J. Single-Electron Oxidation-Initiated Enantioselective Hydrosulfonylation of Olefins Enabled by Photoenzymatic Catalysis. J Am Chem Soc 2024; 146:2748-2756. [PMID: 38214454 DOI: 10.1021/jacs.3c12513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
Controlling the enantioselectivity of hydrogen atom transfer (HAT) reactions has been a long-standing synthetic challenge. While recent advances on photoenzymatic catalysis have demonstrated the great potential of non-natural photoenzymes, all of the transformations are initiated by single-electron reduction of the substrate, with only one notable exception. Herein, we report an oxidation-initiated photoenzymatic enantioselective hydrosulfonylation of olefins using a novel mutant of gluconobacter ene-reductase (GluER-W100F-W342F). Compared to known photoenzymatic systems, our approach does not rely on the formation of an electron donor-acceptor complex between the substrates and enzyme cofactor and simplifies the reaction system by obviating the addition of a cofactor regeneration mixture. More importantly, the GluER variant exhibits high reactivity and enantioselectivity and a broad substrate scope. Mechanistic studies support the proposed oxidation-initiated mechanism and reveal that a tyrosine-mediated HAT process is involved.
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Affiliation(s)
- Qinglong Shi
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiu-Wen Kang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhiyong Liu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Pandaram Sakthivel
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hasil Aman
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Rui Chang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaoyu Yan
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yubing Pang
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shaobo Dai
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory on Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Bei Ding
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Juntao Ye
- Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs, Center for Ultrafast Science and Technology, Frontiers Science Center for Transformative Molecules, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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17
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Zhu C, Yuan Z, Deng Z, Yin D, Zhang Y, Zhou J, Rao Y. Photoenzymatic Enantioselective Synthesis of Oxygen-Containing Benzo-Fused Heterocycles. Angew Chem Int Ed Engl 2023; 62:e202311762. [PMID: 37899302 DOI: 10.1002/anie.202311762] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 10/26/2023] [Accepted: 10/29/2023] [Indexed: 10/31/2023]
Abstract
New-to-nature biocatalysis in organic synthesis has recently emerged as a green and powerful strategy for the preparation of valuable chiral products, among which chiral oxygen-containing benzo-fused heterocycles are important structural motifs in pharmaceutical industry. However, the asymmetric synthesis of these compounds through radical-mediated methods is challenging. Herein, a novel asymmetric radical-mediated photoenzymatic synthesis strategy is developed to realize the efficient enantioselective synthesis of oxygen-containing benzo-fused heterocycles through structure-guided engineering of a flavin-dependent 'ene'-reductase GluER. It shows that variant GluER-W100H could efficiently produce various benzoxepinones, chromanone and indanone with different benzo-fused rings in high yields with great stereoselectivities under visible light. Moreover, these results are well supported by mechanistic experiments, revealing that this photoenzymatic process involves electron donor-acceptor complex formation, single electron transfer and hydrogen atom transfer. Therefore, we provide an alternative green approach for efficient chemoenzymatic synthesis of important chiral skeletons of bioactive pharmaceuticals.
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Affiliation(s)
- Changtong Zhu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, P. R. China
| | - Zhenbo Yuan
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, P. R. China
| | - Zhiwei Deng
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, P. R. China
| | - Dejing Yin
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, P. R. China
| | - Yan Zhang
- School of Life Sciences and Health Engineering, Jiangnan University, 214122, Wuxi, P. R. China
| | - Jingwen Zhou
- Science Center for Future Foods, Jiangnan University, 214122, Wuxi, P. R. China
| | - Yijian Rao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, P. R. China
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18
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Capone M, Dell’Orletta G, Nicholls BT, Scholes GD, Hyster TK, Aschi M, Daidone I. Evidence of a Distinctive Enantioselective Binding Mode for the Photoinduced Radical Cyclization of α-Chloroamides in Ene-Reductases. ACS Catal 2023; 13:15310-15321. [PMID: 38058601 PMCID: PMC10696551 DOI: 10.1021/acscatal.3c03934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/06/2023] [Accepted: 10/30/2023] [Indexed: 12/08/2023]
Abstract
We demonstrate here through molecular simulations and mutational studies the origin of the enantioselectivity in the photoinduced radical cyclization of α-chloroacetamides catalyzed by ene-reductases, in particular the Gluconobacter oxidans ene-reductase and the Old Yellow Enzyme 1, which show opposite enantioselectivity. Our results reveal that neither the π-facial selectivity model nor a protein-induced selective stabilization of the transition states is able to explain the enantioselectivity of the radical cyclization in the studied flavoenzymes. We propose a new enantioinduction scenario according to which enantioselectivity is indeed controlled by transition-state stability; however, the relative stability of the prochiral transition states is not determined by direct interaction with the protein but is rather dependent on an inherent degree of freedom within the substrate itself. This intrinsic degree of freedom, distinct from the traditional π-facial exposure mode, can be controlled by the substrate conformational selection upon binding to the enzyme.
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Affiliation(s)
- Matteo Capone
- Department
of Physical and Chemical Sciences, University
of L’Aquila, via
Vetoio (Coppito 1), L’Aquila 67010, Italy
| | - Gianluca Dell’Orletta
- Department
of Physical and Chemical Sciences, University
of L’Aquila, via
Vetoio (Coppito 1), L’Aquila 67010, Italy
| | - Bryce T. Nicholls
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United States
| | - Gregory D. Scholes
- Department
of Chemistry, Frick Laboratory, Princeton
University, Princeton, New Jersey 08544, United States
| | - Todd K. Hyster
- Department
of Chemistry and Chemical Biology, Cornell
University, Ithaca, New York 14853, United States
| | - Massimiliano Aschi
- Department
of Physical and Chemical Sciences, University
of L’Aquila, via
Vetoio (Coppito 1), L’Aquila 67010, Italy
| | - Isabella Daidone
- Department
of Physical and Chemical Sciences, University
of L’Aquila, via
Vetoio (Coppito 1), L’Aquila 67010, Italy
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19
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Nie X, Ritter CW, Hemming M, Ivlev SI, Xie X, Chen S, Meggers E. Nitrene-Mediated Enantioselective Intramolecular Olefin Oxyamination to Access Chiral γ-Aminomethyl-γ-Lactones. Angew Chem Int Ed Engl 2023:e202314398. [PMID: 37920926 DOI: 10.1002/anie.202314398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 11/01/2023] [Accepted: 11/02/2023] [Indexed: 11/04/2023]
Abstract
Attaching a nitrene precursor to an intramolecular nucleophile allows for a catalytic asymmetric intramolecular oxyamination of alkenes in which the nucleophile adds in an endocyclic position and the amine in an exocyclic fashion. Using chiral-at-ruthenium catalysts, chiral γ-aminomethyl-γ-lactones containing a quaternary carbon in γ-position are provided in high yields (up to 99 %) and with excellent enantioselectivities (up to 99 % ee). DFT calculations support the possibility of both a singlet (concerted oxyamination of the alkene) and triplet pathway (stepwise oxyamination) for the formation of the predominant stereoisomer. γ-Aminomethyl-γ-lactones are versatile chiral building blocks and can be converted to other heterocycles such as δ-lactams, 2-oxazolidinones, and tetrahydrofurans.
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Affiliation(s)
- Xin Nie
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany
| | - Clayton W Ritter
- College of Arts & Sciences, Oberlin College Science Center N381, 119 Woodland St., Oberlin, OH-44074, USA
| | - Marcel Hemming
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany
| | - Sergei I Ivlev
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany
| | - Xiulan Xie
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany
| | - Shuming Chen
- College of Arts & Sciences, Oberlin College Science Center N381, 119 Woodland St., Oberlin, OH-44074, USA
| | - Eric Meggers
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany
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20
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Li M, Zhang T, Shi Y, Duan C. Harnessing Radicals in Confined Supramolecular Environments Made Possible by MOFs. CHEM REC 2023; 23:e202300158. [PMID: 37310416 DOI: 10.1002/tcr.202300158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 05/27/2023] [Indexed: 06/14/2023]
Abstract
Researching and utilizing radical intermediates in organic synthetic chemistry have innovated discoveries in methodology and theory. Reactions concerning free radical species opened new pathways beyond the frame of the two-electron mechanism while commonly characterized as rampant processes lacking selectivity. As a result, research in this field has always focused on the controllable generation of radical species and determining factors of selectivity. Metal-organic frameworks (MOFs) have emerged as compelling candidates as catalysts in radical chemistry. From a catalytic point of view, the porous nature of MOFs entails an inner phase for the reaction that could offer possibilities for the regulation of reactivity and selectivity. From a material science perspecti ve, MOFs are organic-inorganic hybrid materials that integrate functional units in organic compounds and complex forms in the tunable long-ranged periodic structure. In this account, we summarized our progress in the application of MOFs in radical chemistry in three parts: (1) The generation of radical species; (2) The weak interactions and site selectivity; (3) Regio- and stereo-selectivity. The unique role of MOFs play in these paradigms is demonstrated in a supramolecular narrative through the analyses of the multi-constituent collaboration within the MOF and the interactions between MOFs and the intermediates during the reactions.
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Affiliation(s)
- Mochen Li
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, School of Chemistry, Dalian University of Technology, Dalian, 116024, P. R. China
| | - Tiexin Zhang
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, School of Chemistry, Dalian University of Technology, Dalian, 116024, P. R. China
| | - Yusheng Shi
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, School of Chemistry, Dalian University of Technology, Dalian, 116024, P. R. China
| | - Chunying Duan
- State Key Laboratory of Fine Chemicals, School of Chemical Engineering, School of Chemistry, Dalian University of Technology, Dalian, 116024, P. R. China
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21
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Chen H, Fu W, Yang Y. P450-catalyzed atom transfer radical cyclization. Methods Enzymol 2023; 693:31-49. [PMID: 37977735 PMCID: PMC11289761 DOI: 10.1016/bs.mie.2023.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
Cytochromes P450 have been extensively studied for both fundamental enzymology and biotechnological applications. Over the past decade, by taking inspiration from synthetic organic chemistry, new classes of P450-catalyzed reactions that were not previously encountered in the biological world have been developed to address challenging problems in organic chemistry and asymmetric catalysis. In particular, by repurposing and evolving P450 enzymes, stereoselective biocatalytic atom transfer radical cyclization (ATRC) was developed as a new means to impose stereocontrol over transient free radical intermediates. In this chapter, we describe the detailed experimental protocol for the directed evolution of P450 atom transfer radical cyclases. We also delineate protocols for analytical and preparative scale biocatalytic atom transfer radical cyclization processes. These methods will find application in the development of new P450-catalyzed radical reactions, as well as other synthetically useful processes.
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Affiliation(s)
- Heyu Chen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, United States
| | - Wenzhen Fu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, United States
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA, United States; Biomolecular Science and Engineering (BMSE) Program, University of California, Santa Barbara, CA, United States.
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22
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Clements HD, Flynn AR, Nicholls BT, Grosheva D, Lefave SJ, Merriman MT, Hyster TK, Sigman MS. Using Data Science for Mechanistic Insights and Selectivity Predictions in a Non-Natural Biocatalytic Reaction. J Am Chem Soc 2023; 145:17656-17664. [PMID: 37530568 PMCID: PMC10602048 DOI: 10.1021/jacs.3c03639] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
The study of non-natural biocatalytic transformations relies heavily on empirical methods, such as directed evolution, for identifying improved variants. Although exceptionally effective, this approach provides limited insight into the molecular mechanisms behind the transformations and necessitates multiple protein engineering campaigns for new reactants. To address this limitation, we disclose a strategy to explore the biocatalytic reaction space and garner insight into the molecular mechanisms driving enzymatic transformations. Specifically, we explored the selectivity of an "ene"-reductase, GluER-T36A, to create a data-driven toolset that explores reaction space and rationalizes the observed and predicted selectivities of substrate/mutant combinations. The resultant statistical models related structural features of the enzyme and substrate to selectivity and were used to effectively predict selectivity in reactions with out-of-sample substrates and mutants. Our approach provided a deeper understanding of enantioinduction by GluER-T36A and holds the potential to enhance the virtual screening of enzyme mutants.
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Affiliation(s)
- Hanna D Clements
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Autumn R Flynn
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Bryce T Nicholls
- Department of Chemistry and Chemical Biology, Cornell University, 122 Baker Laboratory, Ithaca, New York 14853, United States
| | - Daria Grosheva
- Department of Chemistry and Chemical Biology, Cornell University, 122 Baker Laboratory, Ithaca, New York 14853, United States
| | - Sarah J Lefave
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Morgan T Merriman
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
| | - Todd K Hyster
- Department of Chemistry and Chemical Biology, Cornell University, 122 Baker Laboratory, Ithaca, New York 14853, United States
| | - Matthew S Sigman
- Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, United States
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23
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Ouyang Y, Turek-Herman J, Qiao T, Hyster TK. Asymmetric Carbohydroxylation of Alkenes Using Photoenzymatic Catalysis. J Am Chem Soc 2023; 145:17018-17022. [PMID: 37498747 PMCID: PMC10875682 DOI: 10.1021/jacs.3c06618] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Alkene difunctionalizations enable the synthesis of structurally elaborated products from simple and ubiquitous starting materials in a single chemical step. Carbohydroxylations of olefins represent a family of reactivity that furnish structurally complex alcohols. While examples of this type of three-component coupling have been reported, catalytic asymmetric examples remain elusive. Here, we report an enzyme-catalyzed asymmetric carbohydroxylation of alkenes catalyzed by flavin-dependent "ene"-reductases to produce enantioenriched tertiary alcohols. Seven rounds of protein engineering reshape the enzyme's active site to increase activity and enantioselectivity. Mechanistic studies suggest that C-O bond formation occurs via a 5-endo-trig cyclization with the pendant ketone to afford an α-oxy radical which is oxidized and hydrolyzed to form the product. This work demonstrates photoenzymatic reactions involving "ene"-reductases can terminate radicals via mechanisms other than hydrogen atom transfer, expanding their utility in chemical synthesis.
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Affiliation(s)
- Yao Ouyang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Joshua Turek-Herman
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Tianzhang Qiao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Todd K. Hyster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
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24
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Cheng L, Li D, Mai BK, Bo Z, Cheng L, Liu P, Yang Y. Stereoselective amino acid synthesis by synergistic photoredox-pyridoxal radical biocatalysis. Science 2023; 381:444-451. [PMID: 37499030 PMCID: PMC10444520 DOI: 10.1126/science.adg2420] [Citation(s) in RCA: 26] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 06/20/2023] [Indexed: 07/29/2023]
Abstract
Developing synthetically useful enzymatic reactions that are not known in biochemistry and organic chemistry is an important challenge in biocatalysis. Through the synergistic merger of photoredox catalysis and pyridoxal 5'-phosphate (PLP) biocatalysis, we developed a pyridoxal radical biocatalysis approach to prepare valuable noncanonical amino acids, including those bearing a stereochemical dyad or triad, without the need for protecting groups. Using engineered PLP enzymes, either enantiomeric product could be produced in a biocatalyst-controlled fashion. Synergistic photoredox-pyridoxal radical biocatalysis represents a powerful platform with which to discover previously unknown catalytic reactions and to tame radical intermediates for asymmetric catalysis.
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Affiliation(s)
- Lei Cheng
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, USA
| | - Dian Li
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, USA
| | - Binh Khanh Mai
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Zhiyu Bo
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, USA
| | - Lida Cheng
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, USA
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, USA
- Biomolecular Science and Engineering (BMSE) Program, University of California Santa Barbara, Santa Barbara, California 93106, USA
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25
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Hejna BG, Ganley JM, Shao H, Tian H, Ellefsen JD, Fastuca NJ, Houk KN, Miller SJ, Knowles RR. Catalytic Asymmetric Hydrogen Atom Transfer: Enantioselective Hydroamination of Alkenes. J Am Chem Soc 2023; 145:16118-16129. [PMID: 37432783 PMCID: PMC10544660 DOI: 10.1021/jacs.3c04591] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/13/2023]
Abstract
We report a highly enantioselective radical-based hydroamination of enol esters with sulfonamides jointly catalyzed by an Ir photocatalyst, Brønsted base, and tetrapeptide thiol. This method is demonstrated for the formation of 23 protected β-amino-alcohol products, achieving selectivities up to 97:3 er. The stereochemistry of the product is set through selective hydrogen atom transfer from the chiral thiol catalyst to a prochiral C-centered radical. Structure-selectivity relationships derived from structural variation of both the peptide catalyst and olefin substrate provide key insights into the development of an optimal catalyst. Experimental and computational mechanistic studies indicate that hydrogen-bonding, π-π stacking, and London dispersion interactions are contributing factors for substrate recognition and enantioinduction. These findings further the development of radical-based asymmetric catalysis and contribute to the understanding of the noncovalent interactions relevant to such transformations.
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Affiliation(s)
- Benjamin G. Hejna
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Jacob M. Ganley
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Huiling Shao
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Haowen Tian
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Jonathan D. Ellefsen
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Nicholas J. Fastuca
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Scott J. Miller
- Department of Chemistry, Yale University, New Haven, Connecticut 06520, United States
| | - Robert R. Knowles
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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26
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Fu W, Neris NM, Fu Y, Zhao Y, Krohn-Hansen B, Liu P, Yang Y. Enzyme-controlled stereoselective radical cyclization to arenes enabled by metalloredox biocatalysis. Nat Catal 2023; 6:628-636. [PMID: 38404758 PMCID: PMC10882986 DOI: 10.1038/s41929-023-00986-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 06/13/2023] [Indexed: 02/27/2024]
Abstract
The effective induction of high levels of stereocontrol for free radical-mediated transformations represents a notorious challenge in asymmetric catalysis. Herein, we describe a novel metalloredox biocatalysis strategy to repurpose natural cytochromes P450 to catalyse asymmetric radical cyclisation to arenes through an unnatural electron transfer mechanism. Empowered by directed evolution, engineered P450s allowed diverse radical cyclisation selectivities to be accomplished in a catalyst-controlled fashion: P450arc1 and P450arc2 facilitated enantioconvergent transformations of racemic substrates, giving rise to either enantiomer of the product with excellent total turnover numbers (up to 12,000). In addition to these enantioconvergent variants, another engineered radical cyclase, P450arc3, permitted efficient kinetic resolution of racemic chloride substrates (S factor = 18). Furthermore, computational studies revealed a proton-coupled electron transfer (PCET) mechanism for the radical-polar crossover step, suggesting the potential role of the haem carboxylate as a base catalyst. Collectively, the excellent tunability of this metalloenzyme family provides an exciting platform for harnessing free radical intermediates for asymmetric catalysis.
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Affiliation(s)
- Wenzhen Fu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA
| | - Natalia M. Neris
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA
| | - Yue Fu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Yunlong Zhao
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA
| | - Benjamin Krohn-Hansen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, USA
- Biomolecular Science and Engineering (BMSE) Program, University of California, Santa Barbara, California 93106, USA
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27
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Page CG, Cao J, Oblinsky DG, MacMillan SN, Dahagam S, Lloyd RM, Charnock SJ, Scholes GD, Hyster TK. Regioselective Radical Alkylation of Arenes Using Evolved Photoenzymes. J Am Chem Soc 2023; 145:11866-11874. [PMID: 37199445 PMCID: PMC10859869 DOI: 10.1021/jacs.3c03607] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Substituted arenes are ubiquitous in molecules with medicinal functions, making their synthesis a critical consideration when designing synthetic routes. Regioselective C-H functionalization reactions are attractive for preparing alkylated arenes; however, the selectivity of existing methods is modest and primarily governed by the substrate's electronic properties. Here, we demonstrate a biocatalyst-controlled method for the regioselective alkylation of electron-rich and electron-deficient heteroarenes. Starting from an unselective "ene"-reductase (ERED) (GluER-T36A), we evolved a variant that selectively alkylates the C4 position of indole, an elusive position using prior technologies. Mechanistic studies across the evolutionary series indicate that changes to the protein active site alter the electronic character of the charge transfer (CT) complex responsible for radical formation. This resulted in a variant with a significant degree of ground-state CT in the CT complex. Mechanistic studies on a C2-selective ERED suggest that the evolution of GluER-T36A helps disfavor a competing mechanistic pathway. Additional protein engineering campaigns were carried out for a C8-selective quinoline alkylation. This study highlights the opportunity to use enzymes for regioselective radical reactions, where small molecule catalysts struggle to alter selectivity.
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Affiliation(s)
- Claire G. Page
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Jingzhe Cao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Daniel G. Oblinsky
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Samantha N. MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Shiva Dahagam
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Ruth M. Lloyd
- Prozomix. Building 4, West End Ind. Estate, Haltwhistle, Northumberland, NE49 9HN (UK)
| | - Simon J. Charnock
- Prozomix. Building 4, West End Ind. Estate, Haltwhistle, Northumberland, NE49 9HN (UK)
| | - Gregory D. Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Todd K. Hyster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
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28
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Emmanuel MA, Bender SG, Bilodeau C, Carceller JM, DeHovitz JS, Fu H, Liu Y, Nicholls BT, Ouyang Y, Page CG, Qiao T, Raps FC, Sorigué DR, Sun SZ, Turek-Herman J, Ye Y, Rivas-Souchet A, Cao J, Hyster TK. Photobiocatalytic Strategies for Organic Synthesis. Chem Rev 2023; 123:5459-5520. [PMID: 37115521 PMCID: PMC10905417 DOI: 10.1021/acs.chemrev.2c00767] [Citation(s) in RCA: 35] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Biocatalysis has revolutionized chemical synthesis, providing sustainable methods for preparing various organic molecules. In enzyme-mediated organic synthesis, most reactions involve molecules operating from their ground states. Over the past 25 years, there has been an increased interest in enzymatic processes that utilize electronically excited states accessed through photoexcitation. These photobiocatalytic processes involve a diverse array of reaction mechanisms that are complementary to one another. This comprehensive review will describe the state-of-the-art strategies in photobiocatalysis for organic synthesis until December 2022. Apart from reviewing the relevant literature, a central goal of this review is to delineate the mechanistic differences between the general strategies employed in the field. We will organize this review based on the relationship between the photochemical step and the enzymatic transformations. The review will include mechanistic studies, substrate scopes, and protein optimization strategies. By clearly defining mechanistically-distinct strategies in photobiocatalytic chemistry, we hope to illuminate future synthetic opportunities in the area.
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Affiliation(s)
- Megan A Emmanuel
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Sophie G Bender
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Catherine Bilodeau
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jose M Carceller
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Institute of Chemical Technology (ITQ), Universitat Politècnica de València, València 46022,Spain
| | - Jacob S DeHovitz
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Haigen Fu
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Yi Liu
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Bryce T Nicholls
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Yao Ouyang
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Claire G Page
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Tianzhang Qiao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Felix C Raps
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Damien R Sorigué
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Aix-Marseille University, CEA, CNRS, Institute of Biosciences and Biotechnologies, BIAM Cadarache, 13108 Saint-Paul-lez-Durance, France
| | - Shang-Zheng Sun
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Joshua Turek-Herman
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Yuxuan Ye
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Ariadna Rivas-Souchet
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Jingzhe Cao
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Todd K Hyster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
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29
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Hyster T, Page C, Cao J, Oblinsky D, MacMillan S, Dahagam S, Lloyd R, Charnock S, Scholes G. Regioselective Radical Alkylation of Arenes Using Evolved Photoenzymes. RESEARCH SQUARE 2023:rs.3.rs-2602958. [PMID: 36865242 PMCID: PMC9980219 DOI: 10.21203/rs.3.rs-2602958/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Substituted arenes are ubiquitous in molecules with medicinal functions, making their synthesis a critical consideration when designing synthetic routes. 1,2 Regioselective C-H functionalization reactions are attractive for preparing alkylated arenes, 3-5 however, the selectivity of existing methods is modest and primarily governed by substrate electronic properties. 6,7 Here, we demonstrate a biocatalyst-controlled method for the regioselective alkylation of electron-rich and electron-deficient heteroarenes. Starting from an unselective 'ene'-reductase (ERED) (GluER-T36A), we evolved a variant that selectively alkylates the C4 position of indole, an elusive position using prior technologies. Mechanistic studies across the evolutionary series indicate that changes to the protein active site alter the electronic character of the charge transfer (CT) complex responsible for radical formation. This resulted in a variant with a significant degree of ground state change transfer in the CT complex. Mechanistic studies on a C2 selective ERED suggest that the evolution of GluER-T36A helps disfavor a competing mechanistic pathway. Additional protein engineering campaigns were carried out for a C8 selective quinoline alkylation. This study highlights the opportunity to use enzymes for regioselective reactions where small molecule catalysts struggle to alter selectivity.
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30
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Using enzymes to tame nitrogen-centred radicals for enantioselective hydroamination. Nat Chem 2023; 15:206-212. [PMID: 36376390 DOI: 10.1038/s41557-022-01083-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 10/02/2022] [Indexed: 11/16/2022]
Abstract
The formation of C-N bonds-of great importance to the pharmaceutical industry-can be facilitated enzymatically using nucleophilic and nitrene transfer mechanisms. However, neither natural nor engineered enzymes are known to generate and control nitrogen-centred radicals, which serve as valuable species for C-N bond formation. Here we use flavin-dependent 'ene'-reductases with an exogenous photoredox catalyst to selectively generate amidyl radicals within the protein active site. These enzymes are engineered through directed evolution to catalyse 5-exo, 6-endo, 7-endo, 8-endo, and intermolecular hydroamination reactions with high levels of enantioselectivity. Mechanistic studies suggest that radical initiation occurs via an enzyme-gated mechanism, where the protein thermodynamically activates the substrate for reduction by the photocatalyst. Molecular dynamics studies indicate that the enzymes bind substrates using non-canonical binding interactions, which may serve as a handle to further manipulate reactivity. This approach demonstrates the versatility of these enzymes for controlling the reactivity of high-energy radical intermediates and highlights the opportunity for synergistic catalyst strategies to unlock previously inaccessible enzymatic functions.
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31
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Long C, He Y, Guan Z. Emerging Strategies for Asymmetric Synthesis: Combining Enzyme Promiscuity and Photo‐/Electro‐redox Catalysis. ASIAN J ORG CHEM 2023. [DOI: 10.1002/ajoc.202200685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Chao‐Jiu Long
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering Southwest University Chongqing 400715 P. R. China
| | - Yan‐Hong He
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering Southwest University Chongqing 400715 P. R. China
| | - Zhi Guan
- Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering Southwest University Chongqing 400715 P. R. China
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32
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Duan X, Cui D, Wang Z, Zheng D, Jiang L, Huang WY, Jia YX, Xu J. A Photoenzymatic Strategy for Radical-Mediated Stereoselective Hydroalkylation with Diazo Compounds. Angew Chem Int Ed Engl 2023; 62:e202214135. [PMID: 36478374 DOI: 10.1002/anie.202214135] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
Carbene insertion reactions initiated with diazo compounds have been widely used to develop unnatural enzymatic reactions. However, alternative functionalization of diazo compounds in enzymatic processes has been unexploited. Herein, we describe a photoenzymatic strategy for radical-mediated stereoselective hydroalkylation with diazo compounds. This method generates carbon-centered radicals through an ene reductase catalyzed photoinduced electron transfer process from diazo compounds, enabling the synthesis of γ-stereogenic carbonyl compounds in good yields and stereoselectivities. This study further expands the possible reaction patterns in photo-biocatalysis and offers a new approach to solving the selectivity challenges of radical-mediated reactions.
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Affiliation(s)
- Xinyu Duan
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China
| | - Dong Cui
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China
| | - Zhiguo Wang
- Institute of Aging Research, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, 311121, P. R. China
| | - Dannan Zheng
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China
| | - Linye Jiang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China
| | - Wen-Yu Huang
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China
| | - Yi-Xia Jia
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China.,State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, 200032, P. R. China
| | - Jian Xu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, 310014, P. R. China
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33
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Fu H, Qiao T, Carceller JM, MacMillan SN, Hyster TK. Asymmetric C-Alkylation of Nitroalkanes via Enzymatic Photoredox Catalysis. J Am Chem Soc 2023; 145:787-793. [PMID: 36608280 DOI: 10.1021/jacs.2c12197] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Tertiary nitroalkanes and the corresponding α-tertiary amines represent important motifs in bioactive molecules and natural products. The C-alkylation of secondary nitroalkanes with electrophiles is a straightforward strategy for constructing tertiary nitroalkanes; however, controlling the stereoselectivity of this type of reaction remains challenging. Here, we report a highly chemo- and stereoselective C-alkylation of nitroalkanes with alkyl halides catalyzed by an engineered flavin-dependent "ene"-reductase (ERED). Directed evolution of the old yellow enzyme from Geobacillus kaustophilus provided a triple mutant, GkOYE-G7, capable of synthesizing tertiary nitroalkanes in high yield and enantioselectivity. Mechanistic studies indicate that the excitation of an enzyme-templated charge-transfer complex formed between the substrates and cofactor is responsible for radical initiation. Moreover, a single-enzyme two-mechanism cascade reaction was developed to prepare tertiary nitroalkanes from simple nitroalkenes, highlighting the potential to use one enzyme for two mechanistically distinct reactions.
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Affiliation(s)
- Haigen Fu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Tianzhang Qiao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Jose M Carceller
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States.,Institute of Chemical Technology (ITQ), Universitat Politècnica de València, València 46022, Spain
| | - Samantha N MacMillan
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Todd K Hyster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
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34
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Collaborative catalysis for solar biosynthesis. TRENDS IN CHEMISTRY 2022. [DOI: 10.1016/j.trechm.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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35
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Zachilas I, Kidonakis M, Karapanou MI, Stratakis M. Substitution-Dependent Ring-Opening Hydrosilylation or Dehydrogenative Hydrosilylation of Cyclopropyl Aldehydes and Ketones Catalyzed by Au Nanoparticles. J Org Chem 2022; 87:15914-15924. [DOI: 10.1021/acs.joc.2c02024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Ioannis Zachilas
- Department of Chemistry, University of Crete,
Voutes, Heraklion 71003, Greece
| | - Marios Kidonakis
- Department of Chemistry, University of Crete,
Voutes, Heraklion 71003, Greece
| | | | - Manolis Stratakis
- Department of Chemistry, University of Crete,
Voutes, Heraklion 71003, Greece
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36
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Fu H, Cao J, Qiao T, Qi Y, Charnock SJ, Garfinkle S, Hyster TK. An asymmetric sp 3-sp 3 cross-electrophile coupling using 'ene'-reductases. Nature 2022; 610:302-307. [PMID: 35952713 PMCID: PMC10157439 DOI: 10.1038/s41586-022-05167-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 08/03/2022] [Indexed: 11/09/2022]
Abstract
The catalytic asymmetric construction of Csp3-Csp3 bonds remains one of the foremost challenges in organic synthesis1. Metal-catalysed cross-electrophile couplings (XECs) have emerged as a powerful tool for C-C bond formation2-5. However, coupling two distinct Csp3 electrophiles with high cross-selectivity and stereoselectivity continues as an unmet challenge. Here we report a highly chemoselective and enantioselective Csp3-Csp3 XEC between alkyl halides and nitroalkanes catalysed by flavin-dependent 'ene'-reductases (EREDs). Photoexcitation of the enzyme-templated charge-transfer complex between an alkyl halide and a flavin cofactor enables the chemoselective reduction of alkyl halide over the thermodynamically favoured nitroalkane partner. The key C-C bond-forming step occurs by means of the reaction of an alkyl radical with an in situ-generated nitronate to form a nitro radical anion that collapses to form nitrite and an alkyl radical. An enzyme-controlled hydrogen atom transfer (HAT) affords high levels of enantioselectivity. This reactivity is unknown in small-molecule catalysis and highlights the potential for enzymes to use new mechanisms to address long-standing synthetic challenges.
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Affiliation(s)
- Haigen Fu
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Jingzhe Cao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - Tianzhang Qiao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | | | | | - Samuel Garfinkle
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - Todd K Hyster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
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37
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Lubskyy A, Guo C, Chadwick RJ, Petri-Fink A, Bruns N, Pellizzoni MM. Engineered myoglobin as a catalyst for atom transfer radical cyclisation. Chem Commun (Camb) 2022; 58:10989-10992. [PMID: 36093761 PMCID: PMC9521412 DOI: 10.1039/d2cc03227a] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/30/2022] [Indexed: 11/21/2022]
Abstract
Myoglobin was subjected to site-directed mutagenesis and transformed into a catalyst able to perform atom transfer radical cyclisation reactions, i.e. intramolecular atom transfer radical additions. Replacing the iron-coordinating histidine with serine, or introducing small changes inside or at the entrance of the active site, transformed the completely inactive wild-type myoglobin into an artificial metalloenzyme able to catalyse the 5-exo cyclisation of halogenated unsaturated compounds for the synthesis of γ-lactams. This new-to-nature activity was achieved not only with purified protein but also in crude cell lysate and in whole cells.
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Affiliation(s)
- Andriy Lubskyy
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4,1700, Fribourg, Switzerland.
| | - Chao Guo
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Robert J Chadwick
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
| | - Alke Petri-Fink
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4,1700, Fribourg, Switzerland.
- Department of Chemistry, University of Fribourg, Chemin du Musée 9,1700, Fribourg, Switzerland
| | - Nico Bruns
- Department of Pure and Applied Chemistry, University of Strathclyde, 295 Cathedral Street, Glasgow, G1 1XL, UK.
- Department of Chemistry, Technical University of Darmstadt, Alarich-Weiss-Straße 4, 64287, Darmstadt, Germany
| | - Michela M Pellizzoni
- Adolphe Merkle Institute, University of Fribourg, Chemin des Verdiers 4,1700, Fribourg, Switzerland.
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38
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Cesana PT, Page CG, Harris D, Emmanuel MA, Hyster TK, Schlau-Cohen GS. Photoenzymatic Catalysis in a New Light: Gluconobacter “Ene”-Reductase Conjugates Possessing High-Energy Reactivity with Tunable Low-Energy Excitation. J Am Chem Soc 2022; 144:17516-17521. [DOI: 10.1021/jacs.2c06344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Paul T. Cesana
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Claire G. Page
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Dvir Harris
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Megan A. Emmanuel
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Todd K. Hyster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Gabriela S. Schlau-Cohen
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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39
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Laguerre N, Riehl PS, Oblinsky DG, Emmanuel MA, Black MJ, Scholes GD, Hyster TK. Radical Termination via β-Scission Enables Photoenzymatic Allylic Alkylation Using "Ene"-Reductases. ACS Catal 2022; 12:9801-9805. [PMID: 37859751 PMCID: PMC10586707 DOI: 10.1021/acscatal.2c02294] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Allylations are practical transformations that forge C-C bonds while introducing an alkene for further chemical manipulations. Here, we report a photoenzymatic allylation of α-chloroamides with allyl silanes using flavin-dependent 'ene'-reductases (EREDs). An engineered ERED can catalyze annulative allylic alkylation to prepare 5, 6, and 7-membered lactams with high levels of enantioselectivity. Ultrafast transient absorption spectroscopy indicates that radical termination occurs via β-scission of the silyl group to afford a silyl radical, a distinct mechanism by comparison to traditional radical allylations involving allyl silanes. Moreover, this represents an alternative strategy for radical termination using EREDs. This mechanism was applied to intermolecular couplings involving allyl sulfones and silyl enol ethers. Overall, this method highlights the opportunity for EREDs to catalyze radical termination strategies beyond hydrogen atom transfer.
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Affiliation(s)
| | | | - Daniel G. Oblinsky
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Megan A. Emmanuel
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Michael J. Black
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
| | - Gregory D. Scholes
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14850, United States
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40
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Tasnim T, Ayodele MJ, Pitre SP. Recent Advances in Employing Catalytic Donors and Acceptors in Electron Donor-Acceptor Complex Photochemistry. J Org Chem 2022; 87:10555-10563. [PMID: 35904501 DOI: 10.1021/acs.joc.2c01013] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Electron donor-acceptor (EDA) complexes provide a means to initiate radical reactions under visible light irradiation using substrates that do not absorb visible light individually. Catalytic approaches to complex formation are vital for advancing this synthetic strategy as it decouples the complexation and photogeneration of radicals from substrate functionalization, a limitation inherent to stoichiometric approaches that restricts structural diversity. This Synopsis highlights recent developments in EDA complex photochemistry in which either the donor or acceptor are employed catalytically.
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Affiliation(s)
- Tarannum Tasnim
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences, Stillwater, Oklahoma 74078, United States
| | - Mayokun J Ayodele
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences, Stillwater, Oklahoma 74078, United States
| | - Spencer P Pitre
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences, Stillwater, Oklahoma 74078, United States
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41
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Fu Y, Chen H, Fu W, Garcia-Borràs M, Yang Y, Liu P. Engineered P450 Atom-Transfer Radical Cyclases are Bifunctional Biocatalysts: Reaction Mechanism and Origin of Enantioselectivity. J Am Chem Soc 2022; 144:13344-13355. [PMID: 35830682 PMCID: PMC9339536 DOI: 10.1021/jacs.2c04937] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
New-to-nature radical biocatalysis has recently emerged as a powerful strategy to tame fleeting open-shell intermediates for stereoselective transformations. In 2021, we introduced a novel metalloredox biocatalysis strategy that leverages the innate redox properties of the heme cofactor of P450 enzymes, furnishing new-to-nature atom-transfer radical cyclases (ATRCases) with excellent activity and stereoselectivity. Herein, we report a combined computational and experimental study to shed light on the mechanism and origins of enantioselectivity for this system. Molecular dynamics and quantum mechanics/molecular mechanics (QM/MM) calculations revealed an unexpected role of the key beneficial mutation I263Q. The glutamine residue serves as an essential hydrogen bond donor that engages with the carbonyl moiety of the substrate to promote bromine atom abstraction and enhance the enantioselectivity of radical cyclization. Therefore, the evolved ATRCase is a bifunctional biocatalyst, wherein the heme cofactor enables atom-transfer radical biocatalysis, while the hydrogen bond donor residue further enhances the activity and enantioselectivity. Unlike many enzymatic stereocontrol rationales based on a rigid substrate binding model, our computations demonstrate a high degree of rotational flexibility of the allyl moiety in an enzyme-substrate complex and succeeding intermediates. Therefore, the enantioselectivity is controlled by the radical cyclization transition states rather than the substrate orientation in ground-state complexes in the preceding steps. During radical cyclization, anchoring effects of the Q263 residue and steric interactions with the heme cofactor concurrently control the π-facial selectivity, allowing for highly enantioselective C-C bond formation. Our computational findings are corroborated by experiments with ATRCase mutants generated from site-directed mutagenesis.
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Affiliation(s)
- Yue Fu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Heyu Chen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Wenzhen Fu
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catalisi (IQCC) and Departament de Química, Universitat de Girona, Girona 17003, Spain
| | - Yang Yang
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106, United States
- Biomolecular Science and Engineering (BMSE) Program, University of California, Santa Barbara, California 93106, United States
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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42
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Nicholls BT, Qiao T, Hyster TK. A Photoenzyme for Challenging Lactam Radical Cyclizations. Synlett 2022; 33:1204-1208. [PMID: 37876576 PMCID: PMC10597573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
Reductive radical cyclizations are ubiquitous in organic synthesis and have been applied to the synthesis of structurally complex molecules. N-heterocyclic motifs can be prepared through the cyclization of α-haloamides; however, slow rotation around the amide C-N bond results in preferential formation of an acyclic hydrodehalogenated product. Here, we compare four different methods for preparing γ, δ, ε, and ζ-lactams via radical cyclization. We found that a photoenzymatic method using flavin-dependent 'ene'-reductases affords the highest level of product selectivity. We suggest that through selective binding of the cis amide isomer, the enzyme preorganizes the substrate for cyclization, helping to avoid premature radical termination.
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Affiliation(s)
- Bryce T. Nicholls
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, 14853 USA
| | - Tianzhang Qiao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, 14853 USA
| | - Todd K. Hyster
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, 14853 USA
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43
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Hoffmann N. Heterocyclic Compounds in Enantioselective Photochemical Reactions. HETEROCYCLES 2022. [DOI: 10.1002/9783527832002.ch1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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44
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Robescu MS, Cendron L, Bacchin A, Wagner K, Reiter T, Janicki I, Merusic K, Illek M, Aleotti M, Bergantino E, Hall M. Asymmetric Proton Transfer Catalysis by Stereocomplementary Old Yellow Enzymes for C═C Bond Isomerization Reaction. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Marina S. Robescu
- Department of Biology, University of Padova, Padova, Province of Padova 35131, Italy
| | - Laura Cendron
- Department of Biology, University of Padova, Padova, Province of Padova 35131, Italy
| | - Arianna Bacchin
- Institute of Chemistry, University of Graz, Graz, Styria 8010, Austria
| | - Karla Wagner
- Institute of Chemistry, University of Graz, Graz, Styria 8010, Austria
| | - Tamara Reiter
- Institute of Chemistry, University of Graz, Graz, Styria 8010, Austria
| | - Ignacy Janicki
- Department of Heteroorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Lodz, Lodz Province 90-001, Poland
| | - Kemal Merusic
- Institute of Chemistry, University of Graz, Graz, Styria 8010, Austria
| | - Maximilian Illek
- Institute of Chemistry, University of Graz, Graz, Styria 8010, Austria
| | - Matteo Aleotti
- Institute of Chemistry, University of Graz, Graz, Styria 8010, Austria
| | - Elisabetta Bergantino
- Department of Biology, University of Padova, Padova, Province of Padova 35131, Italy
| | - Mélanie Hall
- Institute of Chemistry, University of Graz, Graz, Styria 8010, Austria
- Field of Excellence BioHealth, University of Graz, Graz, Styria 8010, Austria
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45
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Hwang SY, Song D, Seo EJ, Hollmann F, You Y, Park JB. Triplet-triplet annihilation-based photon-upconversion to broaden the wavelength spectrum for photobiocatalysis. Sci Rep 2022; 12:9397. [PMID: 35672399 PMCID: PMC9174481 DOI: 10.1038/s41598-022-13406-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 05/24/2022] [Indexed: 11/29/2022] Open
Abstract
Photobiocatalysis is a growing field of biocatalysis. Especially light-driven enzyme catalysis has contributed significantly to expanding the scope of synthetic organic chemistry. However, photoenzymes usually utilise a rather narrow wavelength range of visible (sun)light. Triplet-triplet annihilation-based upconversion (TTA-UC) of long wavelength light to shorter wavelength light may broaden the wavelength range. To demonstrate the feasibility of light upconversion we prepared TTA-UC poly(styrene) (PS) nanoparticles doped with platinum(II) octaethylporphyrin (PtOEP) photosensitizer and 9,10-diphenylanthracene (DPA) annihilator (PtOEP:DPA@PS) for application in aqueous solutions. Photoexcitation of PtOEP:DPA@PS nanoparticles with 550 nm light led to upconverted emission of DPA 418 nm. The TTA-UC emission could photoactivate flavin-dependent photodecarboxylases with a high energy transfer efficiency. This allowed the photodecarboxylase from Chlorella variabilis NC64A to catalyse the decarboxylation of fatty acids into long chain secondary alcohols under green light (λ = 550 nm).
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Affiliation(s)
- Se-Yeun Hwang
- Department of Food Science and Biotechnology, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Dayoon Song
- Division of Chemical Engineering and Materials Science, and Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Eun-Ji Seo
- Department of Food Science and Biotechnology, Ewha Womans University, Seoul, 03760, Republic of Korea
| | - Frank Hollmann
- Department of Biotechnology, Delft University of Technology, Van der Maasweg 9, 2629 HZ, Delft, The Netherlands
| | - Youngmin You
- Division of Chemical Engineering and Materials Science, and Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea.
| | - Jin-Byung Park
- Department of Food Science and Biotechnology, Ewha Womans University, Seoul, 03760, Republic of Korea.
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46
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Zhou W, Wu S, Melchiorre P. Tetrachlorophthalimides as Organocatalytic Acceptors for Electron Donor-Acceptor Complex Photoactivation. J Am Chem Soc 2022; 144:8914-8919. [PMID: 35549337 DOI: 10.1021/jacs.2c03546] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Excitation of photoactive electron donor-acceptor (EDA) complexes is an effective way to generate radicals. Applications in a catalytic regime typically use catalytic donors. Herein, we report that readily available electron-poor tetrachlorophthalimides can act as effective organocatalytic acceptors to trigger the formation of EDA complexes with a variety of radical precursors not amenable to previous catalytic methods. Excitation with visible light generates carbon radicals under mild conditions. The versatility of this EDA complex catalytic platform allowed us to develop mechanistically distinct radical reactions, including in combination with a cobalt-based catalytic system. Quantum yield measurements established that a closed catalytic cycle is operational, which hints at the ability of tetrachlorophthalimides to readily turn over and govern each catalytic cycle.
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Affiliation(s)
- Wei Zhou
- ICIQ─Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avinguda Països Catalans 16, 43007 Tarragona, Spain.,Department of Analytical Chemistry and Organic Chemistry, University Rovira i Virgili, 43007 Tarragona, Spain
| | - Shuo Wu
- ICIQ─Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avinguda Països Catalans 16, 43007 Tarragona, Spain.,Department of Analytical Chemistry and Organic Chemistry, University Rovira i Virgili, 43007 Tarragona, Spain
| | - Paolo Melchiorre
- ICIQ─Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avinguda Països Catalans 16, 43007 Tarragona, Spain.,ICREA, Passeig Lluís Companys 23, 08010 Barcelona, Spain
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47
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Huang X, Feng J, Cui J, Jiang G, Harrison W, Zang X, Zhou J, Wang B, Zhao H. Photoinduced chemomimetic biocatalysis for enantioselective intermolecular radical conjugate addition. Nat Catal 2022. [DOI: 10.1038/s41929-022-00777-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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48
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Abstract
Harnessing biocatalysts for novel abiological transformations is a longstanding goal of synthetic chemistry. Combining the merits of biocatalysis and photocatalysis allows for selective transformations fueled by visible light and offers many advantages including new reactivity, high enantioselectivity, greener syntheses, and high yields. Photoinduced electron or energy transfer enables synthetic methodologies that complement conventional two electron processes or offer orthogonal pathways for developing new reactions. Enzymes are well suited and can be tuned by directed evolution to exert control over open-shell intermediates, thereby suppressing undesirable reactions and delivering high chemo- and stereoselectivities. Within the past decade, the combination of biocatalysis and photocatalysis was mainly focused on exploiting light-regenerated cofactors to function native enzymatic activity. However, recent developments have demonstrated that the combination can unlock new-to-nature chemistry. Particularly, the discovery and application of new strategies are well poised to expand the applications of photobiocatalysis.In the past five years, our lab has been studying the combinations of photocatalysis and biocatalysis that can be applied to create new synthetic methodologies and solve challenges in synthetic organic chemistry. Our efforts have expanded the strategies for combining external photocatalysts with enzymes through the construction of a synergistic cooperative stereoconvergent reduction system consisting of photosensitized energy transfer and ene-reductase-catalyzed alkene reduction. Additionally, our efforts have also extended the capability of cofactor-dependent photoenzymatic systems to include enantioselective bimolecular radical hydroalkylations of alkenes by irradiating electron donor-acceptor complexes comprised of enzymatic redox active cofactors and unnatural substrates.In this Account, we highlight strategies developed by our group and others for combining biocatalysis and photocatalysis with the aim of introducing non-natural reactivity to enzymes. Presently, strategies applied to achieve this goal include the repurposing of natural photoenzymes, the elucidation of new photoreactivity within cofactor-dependent enzymes, the combination of external photocatalysts with enzymes, and the construction of artificial photoenzymes. By demonstrating the successful applications of these strategies for achieving selective new-to-nature transformations, we hope to spur interest in expanding the scope of photobiocatalytic systems through the use and extension of these strategies and creation of new strategies. Additionally, we hope to elucidate the intuition in synergizing the unique capabilities of biocatalysis and photocatalysis so that photobiocatalysis can be recognized as a potential solution to difficult challenges in synthetic organic chemistry.
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Affiliation(s)
- Wesley Harrison
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, 600 S. Matthews Avenue, Urbana, Illinois 61801, United States
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
| | - Xiaoqiang Huang
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, 600 S. Matthews Avenue, Urbana, Illinois 61801, United States
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, 600 S. Matthews Avenue, Urbana, Illinois 61801, United States
- DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, 1206 W. Gregory Drive, Urbana, Illinois 61801, United States
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49
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Kumar Roy T, Sreedharan R, Ghosh P, Gandhi T, Maiti D. Ene-Reductase: A Multifaceted Biocatalyst in Organic Synthesis. Chemistry 2022; 28:e202103949. [PMID: 35133702 DOI: 10.1002/chem.202103949] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Indexed: 12/13/2022]
Abstract
Biocatalysis integrate microbiologists, enzymologists, and organic chemists to access the repertoire of pharmaceutical and agrochemicals with high chemoselectivity, regioselectivity, and enantioselectivity. The saturation of carbon-carbon double bonds by biocatalysts challenges the conventional chemical methodology as it bypasses the use of precious metals (in combination with chiral ligands and molecular hydrogen) or organocatalysts. In this line, Ene-reductases (ERs) from the Old Yellow Enzymes (OYEs) family are found to be a prominent asymmetric biocatalyst that is increasingly used in academia and industries towards unparalleled stereoselective trans-hydrogenations of activated C=C bonds. ERs gained prominence as they were used as individual catalysts, multi-enzyme cascades, and in conjugation with chemical reagents (chemoenzymatic approach). Besides, ERs' participation in the photoelectrochemical and radical-mediated process helps to unlock many scopes outside traditional biocatalysis. These up-and-coming methodologies entice the enzymologists and chemists to explore, expand and harness the chemistries displayed by ERs for industrial settings. Herein, we reviewed the last five year's exploration of organic transformations using ERs.
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Affiliation(s)
- Triptesh Kumar Roy
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India
| | - Ramdas Sreedharan
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India
| | - Pintu Ghosh
- Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai, India
| | - Thirumanavelan Gandhi
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632014, Tamil Nadu, India
| | - Debabrata Maiti
- Chemistry Department and Interdisciplinary Program in Climate Studies, Indian Institute of Technology Bombay, Powai, Maharashtra 400076, India
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50
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Zetzsche LE, Chakrabarty S, Narayan ARH. The Transformative Power of Biocatalysis in Convergent Synthesis. J Am Chem Soc 2022; 144:5214-5225. [PMID: 35290055 PMCID: PMC10082969 DOI: 10.1021/jacs.2c00224] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Achieving convergent synthetic strategies has long been a gold standard in constructing complex molecular skeletons, allowing for the rapid generation of complexity in comparatively streamlined synthetic routes. Traditionally, biocatalysis has not played a prominent role in convergent laboratory synthesis, with the application of biocatalysts in convergent strategies primarily limited to the synthesis of chiral fragments. Although the use of enzymes to enable convergent synthetic approaches is relatively new and emerging, combining the efficiency of convergent transformations with the selectivity achievable through biocatalysis creates new opportunities for efficient synthetic strategies. This Perspective provides an overview of recent developments in biocatalytic strategies for convergent transformations and offers insights into the advantages of these methods compared to their small molecule-based counterparts.
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Affiliation(s)
- Lara E. Zetzsche
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Suman Chakrabarty
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Alison R. H. Narayan
- Life Sciences Institute, University of Michigan, Ann Arbor, MI, 48109, USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI, 48109, USA
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