1
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Roy S, Wang Y, Zhao X, Dayananda T, Chu JM, Zhang Y, Fasan R. Stereodivergent Synthesis of Pyridyl Cyclopropanes via Enzymatic Activation of Pyridotriazoles. J Am Chem Soc 2024. [PMID: 39008121 DOI: 10.1021/jacs.4c06103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Hemoproteins have recently emerged as powerful biocatalysts for new-to-nature carbene transfer reactions. Despite this progress, these strategies have remained largely limited to diazo-based carbene precursor reagents. Here, we report the development of a biocatalytic strategy for the stereoselective construction of pyridine-functionalized cyclopropanes via the hemoprotein-mediated activation of pyridotriazoles (PyTz) as stable and readily accessible carbene sources. This method enables the asymmetric cyclopropanation of a variety of olefins, including electron-rich and electrodeficient ones, with high activity, high stereoselectivity, and enantiodivergent selectivity, providing access to mono- and diarylcyclopropanes that incorporate a pyridine moiety and thus two structural motifs of high value in medicinal chemistry. Mechanistic studies reveal a multifaceted role of 7-halogen substitution in the pyridotriazole reagent toward favoring multiple catalytic steps in the transformation. This work provides the first example of asymmetric olefin cyclopropanation with pyridotriazoles, paving the way to the exploitation of these attractive and versatile reagents for enzyme-catalyzed carbene-mediated reactions.
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Affiliation(s)
- Satyajit Roy
- Department of Chemistry and Biochemistry, University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Yining Wang
- Department of Chemistry and Biochemistry, University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
| | - Xinyi Zhao
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point Terrace, Hoboken, New Jersey 07030, United States
| | - Thakshila Dayananda
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, New York 14627, United States
| | - Jia-Min Chu
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point Terrace, Hoboken, New Jersey 07030, United States
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point Terrace, Hoboken, New Jersey 07030, United States
| | - Rudi Fasan
- Department of Chemistry and Biochemistry, University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080, United States
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, New York 14627, United States
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2
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Chaturvedi SS, Vargas S, Ajmera P, Alexandrova AN. Directed Evolution of Protoglobin Optimizes the Enzyme Electric Field. J Am Chem Soc 2024. [PMID: 38848547 DOI: 10.1021/jacs.4c03914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2024]
Abstract
To unravel why computational design fails in creating viable enzymes, while directed evolution (DE) succeeds, our research delves into the laboratory evolution of protoglobin. DE has adapted this protein to efficiently catalyze carbene transfer reactions. We show that the previously proposed enhanced substrate access and binding alone cannot account for increased yields during DE. The 3D electric field in the entire active site is tracked through protein dynamics, clustered using the affinity propagation algorithm, and subjected to principal component analysis. This analysis reveals notable changes in the electric field with DE, where distinct field topologies influence transition state energetics and mechanism. A chemically meaningful field component emerges and takes the lead during DE and facilitates crossing the barrier to carbene transfer. Our findings underscore intrinsic electric field dynamic's influence on enzyme function, the ability of the field to switch mechanisms within the same protein, and the crucial role of the field in enzyme design.
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Affiliation(s)
- Shobhit S Chaturvedi
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Santiago Vargas
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Pujan Ajmera
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
| | - Anastassia N Alexandrova
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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3
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Nam D, Bacik JP, Khade RL, Aguilera MC, Wei Y, Villada JD, Neidig ML, Zhang Y, Ando N, Fasan R. Mechanistic manifold in a hemoprotein-catalyzed cyclopropanation reaction with diazoketone. Nat Commun 2023; 14:7985. [PMID: 38042860 PMCID: PMC10693563 DOI: 10.1038/s41467-023-43559-7] [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: 03/21/2023] [Accepted: 11/14/2023] [Indexed: 12/04/2023] Open
Abstract
Hemoproteins have recently emerged as promising biocatalysts for new-to-nature carbene transfer reactions. However, mechanistic understanding of the interplay between productive and unproductive pathways in these processes is limited. Using spectroscopic, structural, and computational methods, we investigate the mechanism of a myoglobin-catalyzed cyclopropanation reaction with diazoketones. These studies shed light on the nature and kinetics of key catalytic steps in this reaction, including the formation of an early heme-bound diazo complex intermediate, the rate-determining nature of carbene formation, and the cyclopropanation mechanism. Our analyses further reveal the existence of a complex mechanistic manifold for this reaction that includes a competing pathway resulting in the formation of an N-bound carbene adduct of the heme cofactor, which was isolated and characterized by X-ray crystallography, UV-Vis, and Mössbauer spectroscopy. This species can regenerate the active biocatalyst, constituting a non-productive, yet non-destructive detour from the main catalytic cycle. These findings offer a valuable framework for both mechanistic analysis and design of hemoprotein-catalyzed carbene transfer reactions.
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Affiliation(s)
- Donggeon Nam
- Department of Chemistry, University of Rochester, Rochester, NY, 14627, USA
| | - John-Paul Bacik
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA
| | - Rahul L Khade
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | | | - Yang Wei
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, NJ, 07030, USA
| | - Juan D Villada
- Department of Chemistry, University of Rochester, Rochester, NY, 14627, USA
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Michael L Neidig
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK.
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, NJ, 07030, USA.
| | - Nozomi Ando
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, 14853, USA.
| | - Rudi Fasan
- Department of Chemistry, University of Rochester, Rochester, NY, 14627, USA.
- Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, TX, 75080, USA.
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4
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Chatterjee R, Jindal G. Role of mutations in a chemoenzymatic enantiodivergent C(sp 3)-H insertion: exploring the mechanism and origin of stereoselectivity. Chem Sci 2023; 14:8810-8822. [PMID: 37621422 PMCID: PMC10445471 DOI: 10.1039/d3sc02788k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 07/23/2023] [Indexed: 08/26/2023] Open
Abstract
New-to-nature enzymes have emerged as powerful catalysts in recent years for streamlining various stereoselective organic transformations. While synthetic strategies employing engineered enzymes have witnessed proliferating success, there is limited clarity on the mechanistic front and more so when considering molecular-level insights into the role of selected mutations, dramatically escalating catalytic competency and selectivity. We have investigated the mechanism and correlation between mutations and exquisite stereoselectivity of a lactone carbene insertion into the C(sp3)-H bond of substituted aniline, catalyzed by two mutants of a cytochrome P450 variant, "P411" (engineered through directed evolution) in which the axial cysteine has been mutated to serine, utilizing various computational tools. The pivotal role of S264 and L/R328 mutations in the active site has been delineated computationally using two cluster models, thus rationalizing the enantiodivergence. This report provides much-needed insights into the origin of enantiodivergence, furnishing a mechanistic framework for understanding the anchoring effects of H-bond donor residues with the lactone ring. This study is expected to have important implications in the rational design of stereodivergent enzymes and toward successful in silico enzyme designing.
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Affiliation(s)
- Ritwika Chatterjee
- Department of Organic Chemistry, Chemical Sciences Division, Indian Institute of Science Bangalore 560012 India
| | - Garima Jindal
- Department of Organic Chemistry, Chemical Sciences Division, Indian Institute of Science Bangalore 560012 India
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5
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Epping RF, Vesseur D, Zhou M, de Bruin B. Carbene Radicals in Transition-Metal-Catalyzed Reactions. ACS Catal 2023; 13:5428-5448. [PMID: 37123600 PMCID: PMC10127290 DOI: 10.1021/acscatal.3c00591] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 03/21/2023] [Indexed: 04/08/2023]
Abstract
Discovered as organometallic curiosities in the 1970s, carbene radicals have become a staple in modern-day homogeneous catalysis. Carbene radicals exhibit nucleophilic radical-type reactivity orthogonal to classical electrophilic diamagnetic Fischer carbenes. Their successful catalytic application has led to the synthesis of a myriad of carbo- and heterocycles, ranging from simple cyclopropanes to more challenging eight-membered rings. The field has matured to employ densely functionalized chiral porphyrin-based platforms that exhibit high enantio-, regio-, and stereoselectivity. Thus far the focus has largely been on cobalt-based systems, but interest has been growing for the past few years to expand the application of carbene radicals to other transition metals. This Perspective covers the advances made since 2011 and gives an overview on the coordination chemistry, reactivity, and catalytic application of carbene radical species using transition metal complexes and catalysts.
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Affiliation(s)
- Roel F.J. Epping
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - David Vesseur
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Minghui Zhou
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
| | - Bas de Bruin
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Group, van ‘t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH Amsterdam, The Netherlands
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6
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Ma C, Wang S, Sheng Y, Zhao XL, Xing D, Hu W. Synthesis and Characterization of Donor-Acceptor Iron Porphyrin Carbenes and Their Reactivities in N-H Insertion and Related Three-Component Reaction. J Am Chem Soc 2023; 145:4934-4939. [PMID: 36811995 DOI: 10.1021/jacs.2c12155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Iron porphyrin carbenes (IPCs) have been extensively recognized as the reactive intermediates in various iron porphyrin-catalyzed carbene transfer reactions. While donor-acceptor diazo compounds have been frequently used for such transformations, the structures and reactivities of donor-acceptor IPCs are less explored. To date, no crystal structures of donor-acceptor IPC complexes have been reported, and therefore, the involvement of IPC intermediacy for such transformations lacks direct evidence. Here we report the synthesis and NMR characterization of several donor-acceptor IPC complexes from iron porphyrin and corresponding donor-acceptor diazo compounds. The X-ray crystal structure of an IPC complex derived from a morpholine-substituted diazo amide was obtained. The carbene transfer reactivities of those IPCs were tested by the N-H insertion reactions with aniline or morpholine as well as the three-component reaction with aniline and γ,δ-unsaturated α-keto ester based on electrophilic trapping of an ammonium ylide intermediate. Based on these results, IPCs were identified as the real intermediates for iron porphyrin-catalyzed carbene transfer reactions from donor-acceptor diazo compounds.
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Affiliation(s)
- Chaoqun Ma
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Shang Wang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Yuan Sheng
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Xiao-Li Zhao
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Dong Xing
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China
| | - Wenhao Hu
- Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China
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7
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Hakey BM, Leary DC, Martinez JC, Darmon JM, Akhmedov NG, Petersen JL, Milsmann C. Carbene Transfer from a Pyridine Dipyrrolide Iron–Carbene Complex: Reversible Migration of a Diphenylcarbene Ligand into an Iron–Nitrogen Bond. Organometallics 2022. [DOI: 10.1021/acs.organomet.2c00260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Brett M. Hakey
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Dylan C. Leary
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Jordan C. Martinez
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Jonathan M. Darmon
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Novruz G. Akhmedov
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Jeffrey L. Petersen
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Carsten Milsmann
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
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8
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Stroscio GD, Zhou C, Truhlar DG, Gagliardi L. Multiconfiguration Pair-Density Functional Theory Calculations of Iron(II) Porphyrin: Effects of Hybrid Pair-Density Functionals and Expanded RAS and DMRG Active Spaces on Spin-State Orderings. J Phys Chem A 2022; 126:3957-3963. [PMID: 35674705 DOI: 10.1021/acs.jpca.2c02347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iron(II) porphyrins play critical roles in enzymes and synthetic catalysts. Computationally determining the spin-state ordering for even the unsubstituted iron(II) porphyrin (FeP) is challenging due to its large size. Multiconfiguration pair-density functional theory (MC-PDFT), a method capable of accurately capturing correlation with lower cost than comparably accurate methods, was previously used to predict a triplet ground state for FeP across a wide range of active spaces up to (34e, 35o). The purpose of this present MC-PDFT study is to determine the effects of including nonlocal exchange in the energy calculation and of using a larger active space size [DMRG(40e, 42o) and RAS(40, 2, 2; 16, 6, 20)] on the calculated FeP spin-state ordering. The recently developed hybrid MC-PDFT method, which uses a weighted average of the MC-PDFT energy and the energy expectation value of the reference wave function, is applied with a weight of the reference wave function energy of λ. We find that increasing λ stabilizes the quintet relative to the triplets. The hybrid tPBE0 functional (tPBE with λ set to 0.25) consistently predicts a triplet ground state with the quintet lying above by 0.10-0.16 eV, depending on the reference wave function. These values are particularly interesting in light of tPBE0's very strong performance for a diverse set of other systems.
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Affiliation(s)
- Gautam D Stroscio
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, University of Chicago, Chicago, Illinois 60637-5418, United States.,Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Chen Zhou
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Donald G Truhlar
- Department of Chemistry, Chemical Theory Center, and Minnesota Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, United States
| | - Laura Gagliardi
- Department of Chemistry, Chicago Center for Theoretical Chemistry, Pritzker School of Molecular Engineering, James Franck Institute, University of Chicago, Chicago, Illinois 60637-5418, United States.,Argonne National Laboratory, Lemont, Illinois 60439, United States
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9
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Balhara R, Jindal G. Does an Enol Pathway Preclude High Stereoselectivity in Iron-Catalyzed Indole C-H Functionalization via Carbene Insertion? J Org Chem 2022; 87:7919-7933. [PMID: 35652604 DOI: 10.1021/acs.joc.2c00573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
C-H functionalization of indoles via Fe carbenoids presents an attractive strategy to obtain biologically important structural motifs. However, obtaining good stereoselectivity with Fe has been a significant challenge. It is unclear whether the low selectivity is due to a radical pathway or an ionic mechanism involving metal-free species. We therefore present a density functional theory (DFT) study of indole alkylation with diazoacetates catalyzed by Fe(ClO4)TMEDA/spirobisoxazoline and myoglobin. We explore three mechanistic pathways: nucleophilic, radical, and oxocarbenium routes. The nucleophilic pathway is the most feasible with the formation of an enol species that tautomerizes to furnish the alkylated indole. While this mechanism is routinely proposed, the stereochemical model has been conspicuously absent until now. We show that the conventionally invoked enol pathway is not responsible for the low enantiomeric excess. The enol intermediate can stay coordinated to the catalyst via different binding sites placing the enol in proximity to the chiral environment and affecting the stereoselective proton transfer. Both the binding strength and the chiral environment are crucial for obtaining high selectivity. Our study provides the much needed insights for the modest-low selectivities of Fe systems and could help in expediting the discovery of an efficient catalytic system. These mechanistic underpinnings could also be applicable to other metal (Rh, Pd, Cu, etc.)-catalyzed X-H insertion reactions.
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Affiliation(s)
- Reena Balhara
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
| | - Garima Jindal
- Department of Organic Chemistry, Indian Institute of Science, Bangalore, Karnataka 560012, India
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10
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Wang H, Liu Y, Su C, Schulz CE, Fan Y, Bian Y, Li J. Perspectives on Ligand Properties of N-Heterocyclic Carbenes in Iron Porphyrin Complexes. Inorg Chem 2021; 61:847-856. [PMID: 34962794 DOI: 10.1021/acs.inorgchem.1c02444] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There has been considerable research interest in the ligand nature of N-heterocyclic carbenes (NHCs). In this work, two six-coordinate NHC iron porphyrin complexes [FeII(TTP)(1,3-Me2Imd)2] (TTP = tetratolylporphyrin, 1,3-Me2Imd = 1,3-dimethylimidazol-2-ylidene) and [FeIII(TDCPP)(1,3-Me2Imd)2]ClO4 (TDCPP = 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin) are reported. Single-crystal X-ray characterizations demonstrate that both complexes have strongly ruffled conformations and relatively perpendicular ligand orientations which are forced by the sterically bulky 1,3-Me2Imd NHC ligands. Multitemperature (4.2-300 K) and high magnetic field (0-9 T) Mössbauer and low-temperature (4.0 K) EPR spectroscopies definitely confirmed the low-spin states of [FeII(TTP)(1,3-Me2Imd)2] (S = 0) and [FeIII(TDCPP)(1,3-Me2Imd)2]ClO4 (S = 1/2). The similarity of 1,3-Me2Imd and imidazole, as well as the well-established correlations between the ligand nature and spectroscopic characteristics of [FeII,III(Porph)(L)2]0,+ (Porph: porphyrin; L: planar base ligand) species, allowed direct comparisons between the pair of ligands which revealed for the first time that NHC has a stronger π-acceptor ability than imidazoles, in addition to its very strong σ-donation.
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Affiliation(s)
- Haimang Wang
- College of Materials Science and Optoelectronic Technology & CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Yulong Liu
- College of Materials Science and Optoelectronic Technology & CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Chaorui Su
- Department of Chemistry, School of Chemistry and Biological Engineering, Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, and Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
| | - Charles E Schulz
- Department of Physics, Knox College, Galesburg, Illinois 61401, United States
| | - Yingying Fan
- College of Materials Science and Optoelectronic Technology & CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Yanqi Lake, Huairou District, Beijing 101408, China
| | - Yongzhong Bian
- Department of Chemistry, School of Chemistry and Biological Engineering, Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, and Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
| | - Jianfeng Li
- Department of Chemistry, School of Chemistry and Biological Engineering, Beijing Key Laboratory for Science and Application of Functional Molecular and Crystalline Materials, and Daxing Research Institute, University of Science and Technology Beijing, Beijing 100083, China
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11
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Hakey BM, Leary DC, Xiong J, Harris CF, Darmon JM, Petersen JL, Berry JF, Guo Y, Milsmann C. High Magnetic Anisotropy of a Square-Planar Iron-Carbene Complex. Inorg Chem 2021; 60:18575-18588. [PMID: 34431660 DOI: 10.1021/acs.inorgchem.1c01860] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Among Earth-abundant catalyst systems, iron-carbene intermediates that perform C-C bond forming reactions such as cyclopropanation of olefins and C-H functionalization via carbene insertion are rare. Detailed descriptions of the possible electronic structures for iron-carbene bonds are imperative to obtain better mechanistic insights and enable rational catalyst design. Here, we report the first square-planar iron-carbene complex (MesPDPPh)Fe(CPh2), where [MesPDPPh]2- is the doubly deprotonated form of [2,6-bis(5-(2,4,6-trimethylphenyl)-3-phenyl-1H-pyrrol-2-yl)pyridine]. The compound was prepared via reaction of the disubstituted diazoalkane N2CPh2 with (MesPDPPh)Fe(thf) and represents a rare example of a structurally characterized, paramagnetic iron-carbene complex. Temperature-dependent magnetic susceptibility measurements and applied-field Mössbauer spectroscopic studies revealed an orbitally near-degenerate S = 1 ground state with large unquenched orbital angular momentum resulting in high magnetic anisotropy. Spin-Hamiltonian analysis indicated that this S = 1 spin system has uniaxial magnetic properties arising from a ground MS = ±1 non-Kramers doublet that is well-separated from the MS = 0 sublevel due to very large axial zero-field splitting (D = -195 cm-1, E/D = 0.02 estimated from magnetic susceptibility data). This remarkable electronic structure gives rise to a very large, positive magnetic hyperfine field of more than +60 T for the 57Fe nucleus along the easy magnetization axis observed by Mössbauer spectroscopy. Computational analysis with complete active space self-consistent field (CASSCF) calculations provides a detailed electronic structure analysis and confirms that (MesPDPPh)Fe(CPh2) exhibits a multiconfigurational ground state. The majority contribution originates from a configuration best described as a singlet carbene coordinated to an intermediate-spin FeII center with a (dxy)2{(dxz),(dz2)}3(dyz)1(dx2-y2)0 configuration featuring near-degenerate dxz and dz2 orbitals.
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Affiliation(s)
- Brett M Hakey
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Dylan C Leary
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - Jin Xiong
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Caleb F Harris
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Jonathan M Darmon
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Jeffrey L Petersen
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
| | - John F Berry
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Yisong Guo
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, United States
| | - Carsten Milsmann
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States
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12
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Arnett CH, Oyala PH, Agapie T. Probing Redox Non‐Innocence in Iron–Carbene Complexes {Fe=C(H)Ar}
10–11
by
1,2
H and
13
C Pulse Electron Paramagnetic Resonance. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202110704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Charles H. Arnett
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena California 91125 USA
| | - Paul H. Oyala
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena California 91125 USA
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering California Institute of Technology Pasadena California 91125 USA
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13
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Arnett CH, Oyala PH, Agapie T. Probing Redox Non-Innocence in Iron-Carbene Complexes {Fe=C(H)Ar} 10-11 by 1,2 H and 13 C Pulse Electron Paramagnetic Resonance. Angew Chem Int Ed Engl 2021; 60:27220-27224. [PMID: 34695278 DOI: 10.1002/anie.202110704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Indexed: 11/06/2022]
Abstract
We report the synthesis and spectroscopic characterization of a series of iron-carbene complexes in redox states {Fe=C(H)Ar}10-11 . Pulse EPR studies of the 1,2 H and 13 C isotopologues of {Fe=C(H)Ar}11 reveal the high covalency of the Fe-carbene bonding, leading to a more even spin distribution than commonly observed for reduced Fischer carbenes.
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Affiliation(s)
- Charles H Arnett
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, USA
| | - Paul H Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, USA
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California, 91125, USA
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14
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Garcia-Borràs M, Kan SBJ, Lewis RD, Tang A, Jimenez-Osés G, Arnold FH, Houk KN. Origin and Control of Chemoselectivity in Cytochrome c Catalyzed Carbene Transfer into Si-H and N-H bonds. J Am Chem Soc 2021; 143:7114-7123. [PMID: 33909977 DOI: 10.1021/jacs.1c02146] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A cytochrome c heme protein was recently engineered to catalyze the formation of carbon-silicon bonds via carbene insertion into Si-H bonds, a reaction that was not previously known to be catalyzed by a protein. High chemoselectivity toward C-Si bond formation over competing C-N bond formation was achieved, although this trait was not screened for during directed evolution. Using computational and experimental tools, we now establish that activity and chemoselectivity are modulated by conformational dynamics of a protein loop that covers the substrate access to the iron-carbene active species. Mutagenesis of residues computationally predicted to control the loop conformation altered the protein's chemoselectivity from preferred silylation to preferred amination of a substrate containing both N-H and Si-H functionalities. We demonstrate that information on protein structure and conformational dynamics, combined with knowledge of mechanism, leads to understanding of how non-natural and selective chemical transformations can be introduced into the biological world.
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Affiliation(s)
- Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States.,Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Carrer Maria Aurèlia Capmany 69, 17003 Girona, Spain
| | - S B Jennifer Kan
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Russell D Lewis
- Division of Biology and Bioengineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Allison Tang
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | | | - Frances H Arnold
- Division of Biology and Bioengineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States.,Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, United States
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15
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Balhara R, Chatterjee R, Jindal G. A computational approach to understand the role of metals and axial ligands in artificial heme enzyme catalyzed C-H insertion. Phys Chem Chem Phys 2021; 23:9500-9511. [PMID: 33885085 DOI: 10.1039/d1cp00412c] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Engineered heme enzymes such as myoglobin and cytochrome P450s metalloproteins are gaining widespread importance due to their efficiency in catalyzing non-natural reactions. In a recent strategy, the naturally occurring Fe metal in the heme unit was replaced with non-native metals such as Ir, Rh, Co, Cu, etc., and axial ligands to generate artificial metalloenzymes. Determining the best metal-ligand for a chemical transformation is not a trivial task. Here we demonstrate how computational approaches can be used in deciding the best metal-ligand combination which would be highly beneficial in designing new enzymes as well as small molecule catalysts. We have used Density Functional Theory (DFT) to shed light on the enhanced reactivity of an Ir system with varying axial ligands. We look at the insertion of a carbene group generated from diazo precursors via N2 extrusion into a C-H bond. For both Ir(Me) and Fe systems, the first step, i.e., N2 extrusion is the rate determining step. Strikingly, neither the better ligand overlap with 5d orbitals on Ir nor the electrophilicity on the carbene centre play a significant role. A comparison of Fe and Ir systems reveals that a lower distortion in the Ir(Me)-porphyrin on moving from the reactant to the transition state renders it catalytically more active. We notice that for both metal porphyrins, the free energy barriers are affected by axial ligand substitution. Further, for Fe porphyrin, the axial ligand also changes the preferred spin state. We show that for the carbene insertion into the C-H bond, Fe porphyrin systems undergo a stepwise HAT (hydrogen atom transfer) instead of a concerted hydride transfer process. Importantly, we find that the substitution of the axial Me ligand on Ir to imidazole or chloride, or without an axial substitution changes the rate determining step of the reaction. Therefore, an optimum ligand that can balance the barriers for both steps of the catalytic cycle is essential. We subsequently used the QM cluster approach to delineate the protein environment's role and mutations in improving the catalytic activity of the Ir(Me) system.
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Affiliation(s)
- Reena Balhara
- Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012, India.
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16
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Belosludov RV, Nevonen DE, Nemykin VN. Accurate Prediction of the Excited States in the Fully Conjugated Porphyrin Tapes across the Full Spectral Range: A Story of the Interplay between π-π* and Intramolecular Charge-Transfer Transitions in Soft Chromophores. J Phys Chem A 2021; 125:2480-2491. [PMID: 33734683 DOI: 10.1021/acs.jpca.1c00217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The ability of density functional theory (DFT) and time-dependent DFT (TDDFT) methods for the accurate prediction of the energies and oscillator strengths of the excited states in a series of fully conjugated meso-meso β-β β-β triple-linked porphyrin oligomers (porphyrin tapes 2-12) was probed in the gas phase and solution using several exchange-correlation functionals. It was demonstrated that the use of the hybrid B3LYP functional provides a good compromise for the accurate prediction of the localized π-π* and intramolecular charge-transfer transitions, thus allowing confident interpretation of the UV-vis-NIR spectra of porphyrin oligomers. The TDDFT-based sum-over-state (SOS) calculations for the porphyrin tape dimer 2 and trimer 3 as well as parent monomer 1 correctly predicted the signs and shapes of the magnetic circular dichroism (MCD) signals in the low-energy region of the spectra.
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Affiliation(s)
- Rodion V Belosludov
- Institute for Materials Research, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Dustin E Nevonen
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Victor N Nemykin
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada.,Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
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17
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Abucayon EG, Chu JM, Ayala M, Khade RL, Zhang Y, Richter-Addo GB. Insight into the preferential N-binding versus O-binding of nitrosoarenes to ferrous and ferric heme centers. Dalton Trans 2021; 50:3487-3498. [PMID: 33634802 PMCID: PMC8061117 DOI: 10.1039/d0dt03604h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nitrosoarenes (ArNOs) are toxic metabolic intermediates that bind to heme proteins to inhibit their functions. Although much of their biological functions involve coordination to the Fe centers of hemes, the factors that determine N-binding or O-binding of these ArNOs have not been determined. We utilize X-ray crystallography and density functional theory (DFT) analyses of new representative ferrous and ferric ArNO compounds to provide the first theoretical insight into preferential N-binding versus O-binding of ArNOs to hemes. Our X-ray structural results favored N-binding of ArNO to ferrous heme centers, and O-binding to ferric hemes. Results of the DFT calculations rationalize this preferential binding on the basis of the energies of associated spin-states, and reveal that the dominant stabilization forces in the observed ferrous N-coordination and ferric O-coordination are dπ-pπ* and dσ-pπ*, respectively. Our results provide, for the first time, an explanation why in situ oxidation of the ferrous-ArNO compound to its ferric state results in the observed subsequent dissociation of the ligand.
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Affiliation(s)
- Erwin G Abucayon
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA.
| | - Jia-Min Chu
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA.
| | - Megan Ayala
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA.
| | - Rahul L Khade
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA.
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA.
| | - George B Richter-Addo
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA.
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18
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Nemykin VN, Nevonen DE, Ferch LS, Shepit M, Herbert DE, van Lierop J. Accurate Prediction of Mössbauer Hyperfine Parameters in Bis-Axially Coordinated Iron(II) Phthalocyanines Using Density Functional Theory Calculations: A Story of a Single Orbital Revealed by Natural Bond Orbital Analysis. Inorg Chem 2021; 60:3690-3706. [PMID: 33651595 DOI: 10.1021/acs.inorgchem.0c03373] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Density Functional Theory (DFT) calculations coupled with several exchange-correlation functionals were used for the prediction of Mössbauer hyperfine parameters of 36 bis-axially coordinated iron(II) phthalocyanine complexes with the general formulas PcFeL2, PcFeL'L″, and [PcFeX2]2-, including four new compounds. Both gas-phase and PCM calculations using BPW91 and MN12L exchange-correlation functionals were found to accurately predict both Mössbauer quadrupole splittings and the correct trends in experimentally observed isomer shifts. In comparison, hybrid exchange-correlation functionals underestimated quadrupole splittings, while still accurately predicted isomer shifts. Out of ∼40 exchange-correlation functionals tested, only MN12L was found to correctly reproduce quadrupole splitting trends in the PcFeL2 complexes coordinated with phosphorus-donor axial ligands (i.e., P(OnBu)3 ≈ P(OEt)3 < PMe3 < P[(CH2O)2CH2]-p-C6H4NO2 < PEt3 ≈ PnBu3). Natural Bond Orbital (NBO) analysis was successfully used to explain the general trends in the observed quadrupole splitting for all compounds of interest. In particular, the general trends in the quadrupole splitting correlate well with the axial ligand dependent, NBO-predicted population of the 3dz2 orbital of the Fe ion and are reflective of the hypothesis proposed by Ohya and co-workers ( Inorg. Chem., 1984, 23, 1303) on the adaptability of the phthalocyanine's π-system toward Fe-Lax interactions. The first X-ray crystal structure of a PcFeL2 complex with axial phosphine ligands is also reported.
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Affiliation(s)
- Victor N Nemykin
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.,Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Dustin E Nevonen
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Laura S Ferch
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Michael Shepit
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - David E Herbert
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Johan van Lierop
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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19
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Arnett CH, Bogacz I, Chatterjee R, Yano J, Oyala PH, Agapie T. Mixed-Valent Diiron μ-Carbyne, μ-Hydride Complexes: Implications for Nitrogenase. J Am Chem Soc 2020; 142:18795-18813. [PMID: 32976708 DOI: 10.1021/jacs.0c05920] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Binding of N2 by the FeMo-cofactor of nitrogenase is believed to occur after transfer of 4 e- and 4 H+ equivalents to the active site. Although pulse EPR studies indicate the presence of two Fe-(μ-H)-Fe moieties, the structural and electronic features of this mixed valent intermediate remain poorly understood. Toward an improved understanding of this bioorganometallic cluster, we report herein that diiron μ-carbyne complex (P6ArC)Fe2(μ-H) can be oxidized and reduced, allowing for the first time spectral characterization of two EPR-active Fe(μ-C)(μ-H)Fe model complexes linked by a 2 e- transfer which bear some resemblance to a pair of En and En+2 states of nitrogenase. Both species populate S = 1/2 states at low temperatures, and the influence of valence (de)localization on the spectroscopic signature of the μ-hydride ligand was evaluated by pulse EPR studies. Compared to analogous data for the {Fe2(μ-H)}2 state of FeMoco (E4(4H)), the data and analysis presented herein suggest that the hydride ligands in E4(4H) bridge isovalent (most probably FeIII) metal centers. Although electron transfer involves metal-localized orbitals, investigations of [(P6ArC)Fe2(μ-H)]+1 and [(P6ArC)Fe2(μ-H)]-1 by pulse EPR revealed that redox chemistry induces significant changes in Fe-C covalency (-50% upon 2 e- reduction), a conclusion further supported by X-ray absorption spectroscopy, 57Fe Mössbauer studies, and DFT calculations. Combined, our studies demonstrate that changes in covalency buffer against the accumulation of excess charge density on the metals by partially redistributing it to the bridging carbon, thereby facilitating multielectron transformations.
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Affiliation(s)
- Charles H Arnett
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Isabel Bogacz
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Ruchira Chatterjee
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Junko Yano
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Paul H Oyala
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Theodor Agapie
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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20
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Casali E, Gallo E, Toma L. An In-Depth Computational Study of Alkene Cyclopropanation Catalyzed by Fe(porphyrin)(OCH 3) Complexes. The Environmental Effects on the Energy Barriers. Inorg Chem 2020; 59:11329-11336. [PMID: 32799510 PMCID: PMC8009515 DOI: 10.1021/acs.inorgchem.0c00912] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Iron porphyrin methoxy complexes, of the general formula [Fe(porphyrin)(OCH3)], are able to catalyze the reaction of diazo compounds with alkenes to give cyclopropane products with very high efficiency and selectivity. The overall mechanism of these reactions was thoroughly investigated with the aid of a computational approach based on density functional theory calculations. The energy profile for the processes catalyzed by the oxidized [FeIII(Por)(OCH3)] (Por = porphine) as well as the reduced [FeII(Por)(OCH3)]- forms of the iron porphyrin was determined. The main reaction step is the same in both of the cases, that is, the one leading to the terminal-carbene intermediate [Fe(Por)(OCH3)(CHCO2Et)] with simultaneous dinitrogen loss; however, the reduced species performs much better than the oxidized one. Contrarily to the iron(III) profile in which the carbene intermediate is directly obtained from the starting reactant complex, the favored iron(II) process is more intricate. The initially formed reactant adduct between [FeII(Por)(OCH3)]- and ethyl diazoacetate (EDA) is converted into a closer reactant adduct, which is in turn converted into the terminal iron porphyrin carbene [Fe(Por)(OCH3)(CHCO2Et)]-. The two corresponding transition states are almost isoenergetic, thus raising the question of whether the rate-determining step corresponds to dinitrogen loss or to the previous structural and electronic rearrangement. The ethylene addition to the terminal carbene is a downhill process, which, on the open-shell singlet surface, presents a defined but probably short-living diradicaloid intermediate, though other spin-state surfaces do not show this intermediate allowing a direct access to the cyclopropane product. For the crucial stationary points, the more complex catalyst [Fe(2)(OCH3)], in which a sterically hindered chiral bulk is mounted onto the porphyrin, was investigated. The corresponding computational data disclose the very significant effect of the porphyrin skeleton on the reaction energy profile. Though the geometrical features around the reactive core of the system remain unchanged, the energy barriers become much lower, thus revealing the profound effects that can be exerted by the three-dimensional organic scaffold surrounding the reaction site.
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Affiliation(s)
- Emanuele Casali
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
| | - Emma Gallo
- Dipartimento di Chimica, Università di Milano, Via Golgi 19, 20133 Milano, Italy
| | - Lucio Toma
- Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia, Italy
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21
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Stroscio GD, Srnec M, Hadt RG. Multireference Ground and Excited State Electronic Structures of Free- versus Iron Porphyrin-Carbenes. Inorg Chem 2020; 59:8707-8715. [PMID: 32510941 DOI: 10.1021/acs.inorgchem.0c00249] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Iron porphyrin carbenes (IPCs) are important reaction intermediates in engineered carbene transferase enzymes and homogeneous catalysis. However, discrepancies between theory and experiment complicate the understanding of IPC electronic structure. In the literature, this has been framed as whether the ground state is an open- vs closed-shell singlet (OSS vs CSS). Here we investigate the structurally dependent ground and excited spin-state energetics of a free carbene and its IPC analogs with variable trans axial ligands. In particular, for IPCs, multireference ab initio wave function methods are more consistent with experiment and predict a mixed singlet ground state that is dominated by the CSS (Fe(II) ← {:C(X)Y}0) configuration (i.e., electrophilic carbene) but that also has a small, non-negligible contribution from an Fe(III)-{C(X)Y}-• configuration (hole in d(xz), i.e., radical carbene). In the multireference approach, the "OSS-like" excited states are metal-to-ligand charge transfer (MLCT) in nature and are energetically well above the CSS-dominated ground state. The first, lowest energy of these "OSS-like" excited states is predicted to be heavily weighted toward the Fe(III)-{C(X)Y}-• (hole in d(yz)) configuration. As expected from exchange considerations, this state falls energetically above a triplet of the same configuration. Furthermore, potential energy surfaces (PESs) along the IPC Fe-C(carbene) bond elongation exhibit increasingly strong mixings between CSS/OSS characters, with the Fe(III)-{C(X)Y}-• configuration (hole in d(xz)) growing in weight in the ground state during bond elongation. The relative degree of electrophilic/radical carbene character along this structurally relevant PES can potentially play a role in reactivity and selectivity patterns in catalysis. Future studies on IPC reaction coordinates should evaluate contributions from ground and excited state multireference character.
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Affiliation(s)
- Gautam D Stroscio
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
| | - Martin Srnec
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Prague 8, 18223 Czech Republic
| | - Ryan G Hadt
- Division of Chemistry and Chemical Engineering, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125, United States
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22
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Wang HX, Wan Q, Low KH, Zhou CY, Huang JS, Zhang JL, Che CM. Stable group 8 metal porphyrin mono- and bis(dialkylcarbene) complexes: synthesis, characterization, and catalytic activity. Chem Sci 2020; 11:2243-2259. [PMID: 32180931 PMCID: PMC7047983 DOI: 10.1039/c9sc05432d] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 12/30/2019] [Indexed: 12/17/2022] Open
Abstract
Alkyl-substituted carbene (CHR or CR2, R = alkyl) complexes have been extensively studied for alkylcarbene (CHR) ligands coordinated with high-valent early transition metal ions (a.k.a. Schrock carbenes or alkylidenes), yet dialkylcarbene (CR2) complexes remain less developed with bis(dialkylcarbene) species being little (if at all) explored. Herein, several group 8 metal porphyrin dialkylcarbene complexes, including Fe- and Ru-mono(dialkylcarbene) complexes [M(Por)(Ad)] (1a,b, M = Fe, Por = porphyrinato dianion, Ad = 2-adamantylidene; 2a,b, M = Ru) and Os-bis(dialkylcarbene) complexes [Os(Por)(Ad)2] (3a-c), are synthesized and crystallographically characterized. Detailed investigations into their electronic structures reveal that these complexes are formally low-valent M(ii)-carbene in nature. These complexes display remarkable thermal stability and chemical inertness, which are rationalized by a synergistic effect of strong metal-carbene covalency, hyperconjugation, and a rigid diamondoid carbene skeleton. Various spectroscopic techniques and DFT calculations suggest that the dialkylcarbene Ad ligand is unique compared to other common carbene ligands as it acts as both a potent σ-donor and π-acceptor; its unique electronic and structural features, together with the steric effect of the porphyrin macrocycle, make its Fe porphyrin complex 1a an active and robust catalyst for intermolecular diarylcarbene transfer reactions including cyclopropanation (up to 90% yield) and X-H (X = S, N, O, C) insertion (up to 99% yield) reactions.
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Affiliation(s)
- Hai-Xu Wang
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
| | - Qingyun Wan
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
| | - Kam-Hung Low
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
| | - Cong-Ying Zhou
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
- College of Chemistry and Materials Science , Jinan University , Guangzhou , China
| | - Jie-Sheng Huang
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
| | - Jun-Long Zhang
- Beijing National Laboratory for Molecular Sciences , College of Chemistry and Molecular Engineering , Peking University , Beijing , China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong SAR , China .
- HKU Shenzhen Institute of Research & Innovation , Shenzhen , China
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23
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DeJesus JF, Jenkins DM. A Chiral Macrocyclic Tetra-N-Heterocyclic Carbene Yields an "All Carbene" Iron Alkylidene Complex. Chemistry 2020; 26:1429-1435. [PMID: 31788868 PMCID: PMC7024548 DOI: 10.1002/chem.201905360] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Indexed: 01/12/2023]
Abstract
The first chiral macrocyclic tetra-N-heterocyclic carbene (NHC) ligand has been synthesized. The macrocycle, prepared in high yield and large scale, was ligated onto palladium and iron to give divalent C2 -symmetric square planar complexes. Multinuclear NMR and single crystal X-ray diffraction demonstrated that there are two distinct NHCs on each ligand, due to the bridging chiral cyclohexane. Oxidation of the iron(II) complex with trimethylamine N-oxide yielded a bridging oxo complex. Diazodiphenylmethane reacted with the iron(II) complex at room temperature to give a paramagnetic diazoalkane complex; the same reaction yielded the "all carbene" complex at elevated temperature. Electrochemical measurements support the assignment of the "all carbene" complex being an alkylidene. Notably, the diazoalkane complex can be directly transformed into the alkylidene complex, which had not been previously demonstrated on iron. Finally, a test catalytic reaction with a diazoalkane on the iron(II) complex does not yield the expected cyclopropane, but actually the azine compound.
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Affiliation(s)
- Joseph F DeJesus
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - David M Jenkins
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
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24
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Li X, Dong L, Liu Y. Theoretical Study of Iron Porphyrin Nitrene: Formation Mechanism, Electronic Nature, and Intermolecular C–H Amination. Inorg Chem 2020; 59:1622-1632. [DOI: 10.1021/acs.inorgchem.9b02216] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Xinyi Li
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
| | - Lihua Dong
- School of Chemistry and Chemical Engineering, Qilu Normal University, Jinan, Shandong 250013, China
| | - Yongjun Liu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan, Shandong 250100, China
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25
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Manna D, Lo R, Hobza P. Spin modification of iron(ii) complexes via covalent (dative) and dispersion guided non-covalent bonding with N-heterocyclic carbenes: DFT, DLPNO-CCSD(T) and MCSCF studies. Dalton Trans 2020; 49:164-170. [DOI: 10.1039/c9dt04334a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Spin crossover from high spin Fe(ii)-phthalocyanine to low or intermediate spin via either dative covalent or non-covalent interaction by just varying the substituent using the same core ligand.
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Affiliation(s)
- Debashree Manna
- Institute of Organic Chemistry and Biochemistry
- Academy of Sciences of the Czech Republic
- 16610 Prague 6
- Czech Republic
- Regional Centre of Advanced Technologies and Materials
| | - Rabindranath Lo
- Institute of Organic Chemistry and Biochemistry
- Academy of Sciences of the Czech Republic
- 16610 Prague 6
- Czech Republic
- Regional Centre of Advanced Technologies and Materials
| | - Pavel Hobza
- Institute of Organic Chemistry and Biochemistry
- Academy of Sciences of the Czech Republic
- 16610 Prague 6
- Czech Republic
- Regional Centre of Advanced Technologies and Materials
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26
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Damiano C, Sonzini P, Gallo E. Iron catalysts with N-ligands for carbene transfer of diazo reagents. Chem Soc Rev 2020; 49:4867-4905. [DOI: 10.1039/d0cs00221f] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This review provides an overview of the catalytic activity of iron complexes of nitrogen ligands in driving carbene transfers towards CC, C–H and X–H bonds. The reactivity of diazo reagents is discussed as well as the proposed reaction mechanisms.
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Affiliation(s)
| | - Paolo Sonzini
- Department of Chemistry
- University of Milan
- 20133 Milan
- Italy
| | - Emma Gallo
- Department of Chemistry
- University of Milan
- 20133 Milan
- Italy
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27
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Liu Y, You T, Wang HX, Tang Z, Zhou CY, Che CM. Iron- and cobalt-catalyzed C(sp3)–H bond functionalization reactions and their application in organic synthesis. Chem Soc Rev 2020; 49:5310-5358. [DOI: 10.1039/d0cs00340a] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
This review highlights the developments in iron and cobalt catalyzed C(sp3)–H bond functionalization reactions with emphasis on their applications in organic synthesis, i.e. natural products and pharmaceuticals synthesis and/or modification.
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Affiliation(s)
- Yungen Liu
- Department of Chemistry
- Southern University of Science and Technology
- Shenzhen
- P. R. China
| | - Tingjie You
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Hai-Xu Wang
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Zhou Tang
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Cong-Ying Zhou
- Department of Chemistry
- State Key Laboratory of Synthetic Chemistry
- The University of Hong Kong
- Hong Kong
- P. R. China
| | - Chi-Ming Che
- Department of Chemistry
- Southern University of Science and Technology
- Shenzhen
- P. R. China
- Department of Chemistry
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28
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Cailler LP, Clémancey M, Barilone J, Maldivi P, Latour JM, Sorokin AB. Comparative Study of the Electronic Structures of μ-Oxo, μ-Nitrido, and μ-Carbido Diiron Octapropylporphyrazine Complexes and Their Catalytic Activity in Cyclopropanation of Olefins. Inorg Chem 2019; 59:1104-1116. [DOI: 10.1021/acs.inorgchem.9b02718] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lucie P. Cailler
- Institut de Recherches sur la Catalyse et l’Environnement de Lyon IRCELYON, UMR 5256, CNRS - Université Lyon 1, 2 avenue A. Einstein, 69626 Villeurbanne cedex, France
| | - Martin Clémancey
- Univ. Grenoble-Alpes, CEA, CNRS, IRIG-SyMMES, Grenoble 38000, France
| | - Jessica Barilone
- Univ. Grenoble-Alpes, CEA, CNRS, IRIG, CBM, Grenoble 38000, France
- Univ. Grenoble-Alpes, CEA, CNRS, IRIG-SyMMES, Grenoble 38000, France
| | - Pascale Maldivi
- Univ. Grenoble-Alpes, CEA, CNRS, IRIG, CBM, Grenoble 38000, France
| | - Jean-Marc Latour
- Univ. Grenoble-Alpes, CEA, CNRS, IRIG-SyMMES, Grenoble 38000, France
| | - Alexander B. Sorokin
- Institut de Recherches sur la Catalyse et l’Environnement de Lyon IRCELYON, UMR 5256, CNRS - Université Lyon 1, 2 avenue A. Einstein, 69626 Villeurbanne cedex, France
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29
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Abstract
On the occasion of Professor Frances H. Arnold's recent acceptance of the 2018 Nobel Prize in Chemistry, we honor her numerous contributions to the fields of directed evolution and biocatalysis. Arnold pioneered the development of directed evolution methods for engineering enzymes as biocatalysts. Her highly interdisciplinary research has provided a ground not only for understanding the mechanisms of enzyme evolution but also for developing commercially viable enzyme biocatalysts and biocatalytic processes. In this Account, we highlight some of her notable contributions in the past three decades in the development of foundational directed evolution methods and their applications in the design and engineering of enzymes with desired functions for biocatalysis. Her work has created a paradigm shift in the broad catalysis field.
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Affiliation(s)
- Rudi Fasan
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - S. B. Jennifer Kan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Huimin Zhao
- Departments of Chemical and Biomolecular Engineering, Chemistry, and Biochemistry, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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30
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Zhang Y. Computational Investigations of Heme Carbenes and Heme Carbene Transfer Reactions. Chemistry 2019; 25:13231-13247. [DOI: 10.1002/chem.201901984] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/19/2019] [Indexed: 12/15/2022]
Affiliation(s)
- Yong Zhang
- Department of Chemistry and Chemical Biology Stevens Institute of Technology 1 Castle Point on Hudson Hoboken NJ 07030 USA
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31
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Schippers ECF, Nurttila SS, Oudsen JPH, Tromp M, Dzik WI, van der Vlugt JI, Reek JNH. [FeFe]-Hydrogenase Mimic Employing κ 2- C, N-Pyridine Bridgehead Catalyzes Proton Reduction at Mild Overpotential. Eur J Inorg Chem 2019; 2019:2510-2517. [PMID: 31244551 PMCID: PMC6582614 DOI: 10.1002/ejic.201900405] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Indexed: 01/06/2023]
Abstract
Two novel κ2‐C,N‐pyridine bridged [FeFe]‐H2ase mimics (1 and 2) have been prepared and are shown to function as efficient molecular catalysts for electrocatalytic proton reduction. The elemental and structural composition of the complexes are confirmed by NMR and IR spectroscopy, high‐resolution mass spectrometry and single‐crystal X‐ray diffraction. Electrochemical investigations reveal that the complexes reduce protons at their first reduction potential, resulting in the lowest overpotential (120 mV) ever reported for [FeFe]‐H2ase mimics in proton reduction catalysis when mild acid (phenol) is used as proton source.
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Affiliation(s)
- Esther C F Schippers
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Van 't Hoff Institute for Molecular Sciences University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
| | - Sandra S Nurttila
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Van 't Hoff Institute for Molecular Sciences University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
| | - Jean-Pierre H Oudsen
- Sustainable Materials Characterization Van 't Hoff Institute for Molecular Sciences University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
| | - Moniek Tromp
- Sustainable Materials Characterization Van 't Hoff Institute for Molecular Sciences University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
| | - Wojciech I Dzik
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Van 't Hoff Institute for Molecular Sciences University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
| | - Jarl Ivar van der Vlugt
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Van 't Hoff Institute for Molecular Sciences University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
| | - Joost N H Reek
- Homogeneous, Supramolecular and Bio-Inspired Catalysis Van 't Hoff Institute for Molecular Sciences University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands
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32
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Wang HX, Wan Q, Wu K, Low KH, Yang C, Zhou CY, Huang JS, Che CM. Ruthenium(II) Porphyrin Quinoid Carbene Complexes: Synthesis, Crystal Structure, and Reactivity toward Carbene Transfer and Hydrogen Atom Transfer Reactions. J Am Chem Soc 2019; 141:9027-9046. [DOI: 10.1021/jacs.9b03357] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Hai-Xu Wang
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Qingyun Wan
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Kai Wu
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Kam-Hung Low
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Chen Yang
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Cong-Ying Zhou
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Jie-Sheng Huang
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, China
- HKU Shenzhen Institute of Research & Innovation, Shenzhen, China
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33
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Khade RL, Chandgude AL, Fasan R, Zhang Y. Mechanistic Investigation of Biocatalytic Heme Carbenoid Si-H Insertions. ChemCatChem 2019; 11:3101-3108. [PMID: 31428208 DOI: 10.1002/cctc.201801755] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Recent studies reported the development of biocatalytic heme carbenoid Si-H insertions for the selective formation of carbon-silicon bonds, but many mechanistic questions remain unaddressed. To this end, a DFT mechanistic investigation was performed which reveals an FeII-based concerted hydride transfer mechanism with early transition state feature. The results from these computational analyses are consistent with experimental data of radical trapping, kinetic isotope effects, and structure-reactivity data using engineered variants of hemoproteins. Detailed geometric and electronic profiles along the heme catalyzed Si-H insertion pathways were provided to help understand the origin of experimental reactivity trends. Quantitative relationships between reaction barriers and some properties such as charge transfer from substrate to heme carbene and Si-H bond length change from reactant to transition state were found. Results suggest catalyst modifications to facilitate the charge transfer from the silane substrate to the carbene, which was determined to be a major electronic driving force of this reaction, should enable the development of improved biocatalysts for Si-H carbene insertion reactions.
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Affiliation(s)
- Rahul L Khade
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point on Hudson, Hoboken, NJ 07030 (USA)
| | - Ajay L Chandgude
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY 14627 (USA)
| | - Rudi Fasan
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY 14627 (USA)
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point on Hudson, Hoboken, NJ 07030 (USA)
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34
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Chen K, Huang X, Zhang SQ, Zhou AZ, Kan SBJ, Hong X, Arnold FH. Engineered Cytochrome c-Catalyzed Lactone-Carbene B-H Insertion. Synlett 2019; 30:378-382. [PMID: 30930550 PMCID: PMC6436545 DOI: 10.1055/s-0037-1611662] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Previous work has demonstrated that variants of a heme protein, Rhodothermus marinus cytochrome c (Rma cyt c), catalyze abiological carbene boron-hydrogen (B-H) bond insertion with high efficiency and selectivity. Here we investigated this carbon-boron bondforming chemistry with cyclic, lactone-based carbenes. Using directed evolution, we obtained a Rma cyt c variant BOR LAC that shows high selectivity and efficiency for B-H insertion of 5- and 6-membered lactone carbenes (up to 24,500 total turnovers and 97.1:2.9 enantiomeric ratio). The enzyme shows low activity with a 7-membered lactone carbene. Computational studies revealed a highly twisted geometry of the 7membered lactone carbene intermediate relative to 5- and 6-membered ones. Directed evolution of cytochrome c together with computational characterization of key iron-carbene intermediates has allowed us to expand the scope of enzymatic carbene B-H insertion to produce new lactone-based organoborons.
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Affiliation(s)
- Kai Chen
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, Pasadena, CA 91125, USA
| | - Xiongyi Huang
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, Pasadena, CA 91125, USA
| | - Shuo-Qing Zhang
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 31007, P. R. of China
| | - Andrew Z Zhou
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, Pasadena, CA 91125, USA
| | - S B Jennifer Kan
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, Pasadena, CA 91125, USA
| | - Xin Hong
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 31007, P. R. of China
| | - Frances H Arnold
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, Pasadena, CA 91125, USA
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35
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Tinoco A, Wei Y, Bacik JP, Carminati DM, Moore EJ, Ando N, Zhang Y, Fasan R. Origin of high stereocontrol in olefin cyclopropanation catalyzed by an engineered carbene transferase. ACS Catal 2019; 9:1514-1524. [PMID: 31134138 DOI: 10.1021/acscatal.8b04073] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent advances in metalloprotein engineering have led to the development of a myoglobin-based catalyst, Mb(H64V,V68A), capable of promoting the cyclopropanation of vinylarenes with high efficiency and high diastereo- and enantioselectivity. Whereas many enzymes evolved in nature often exhibit catalytic proficiency and exquisite stereoselectivity, how these features are achieved for a non-natural reaction has remained unclear. In this work, the structural determinants responsible for chiral induction and high stereocontrol in Mb(H64V,V68A)-catalyzed cyclopropanation were investigated via a combination of crystallographic, computational (DFT), and structure-activity analyses. Our results show the importance of steric complementarity and non-covalent interactions involving first-sphere active site residues, heme-carbene, and the olefin substrate, in dictating the stereochemical outcome of the cyclopropanation reaction. High stereocontrol is achieved through two major mechanisms. First, by enforcing a specific conformation of the heme-bound carbene within the active site. Second, by controlling the geometry of attack of the olefin on the carbene via steric occlusion, attractive van der Waals forces and protein-mediated π-π interactions with the olefin substrate. These insights could be leveraged to expand the substrate scope of the myoglobin-based cyclopropanation catalyst toward non-activated olefins and to increase its cyclopropanation activity in the presence of a bulky α-diazo-ester. This work sheds first light into the origin of enzyme-catalyzed enantioselective cyclopropanation, furnishing a mechanistic framework for both understanding the reactivity of current systems and guiding the future development of biological catalysts for this class of synthetically important, abiotic transformations.
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Affiliation(s)
- Antonio Tinoco
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Yang Wei
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - John-Paul Bacik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Daniela M. Carminati
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Eric J. Moore
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Nozomi Ando
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Rudi Fasan
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
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36
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Wang H, Schulz CE, Wei X, Li J. New Insights into the Ligand Nature of Carbene: Synthesis and Characterizations of Six-Coordinate Iron(II) Carbene Porphyrin Complexes. Inorg Chem 2018; 58:143-151. [PMID: 30565937 DOI: 10.1021/acs.inorgchem.8b02043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Charles E. Schulz
- Department of Physics, Knox College, Galesburg, Illinois 61401, United States
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37
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Chen K, Zhang SQ, Brandenberg OF, Hong X, Arnold FH. Alternate Heme Ligation Steers Activity and Selectivity in Engineered Cytochrome P450-Catalyzed Carbene-Transfer Reactions. J Am Chem Soc 2018; 140:16402-16407. [DOI: 10.1021/jacs.8b09613] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Kai Chen
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, Pasadena, California 91125, United States
| | - Shuo-Qing Zhang
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, P. R. China
| | - Oliver F. Brandenberg
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, Pasadena, California 91125, United States
| | - Xin Hong
- Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, P. R. China
| | - Frances H. Arnold
- Division of Chemistry and Chemical Engineering 210-41, California Institute of Technology, Pasadena, California 91125, United States
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38
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Peng Q, Sage JT, Liu Y, Wang Z, Hu MY, Zhao J, Alp EE, Scheidt WR, Li J. How Does a Heme Carbene Differ from Diatomic Ligated (NO, CO, and CN -) Analogues in the Axial Bond? Inorg Chem 2018; 57:8788-8795. [PMID: 30010336 DOI: 10.1021/acs.inorgchem.8b00574] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Compared to well studied diatomic ligands (NO, CN-, CO), the axial bonds of carbene hemes is much less known although its significance in biological chemistry. The unusually large quadrupole splitting (Δ EQ = +2.2 mm·s-1) and asymmetric parameter (η = 0.9) of the five-coordinate heme carbene [Fe(TTP)(CCl2)], which is the largest among all known low spin ferrohemes, has driven investigations by means of Mössbauer effect Nuclear Resonance Vibrational Spectroscopy (NRVS). Three distinct measurements on one single crystal (two in-plane and one out-of-plane) have demonstrated comprehensive vibrational structures including stretch (429) and bending modes (472 cm-1) of the axial Fe-CCl2, and revealed iron vibrational anisotropy in three orthogonal directions for the first time. Frontier orbital analysis especially comparisons with diatomic analogues (NO, CN-, CO) suggest that CCl2, similar to NO, has led to strong but anisotropic π bonding in a ligand-based "4C"-coordinate which induced the vibrational anisotropies and very large Mössbauer parameters. This is contrasted to CN- and CO complexes which possess a porphyrin-based "4N"-coordinate electronic and vibrational structures due to inherent on-axis linear ligation.
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Affiliation(s)
- Qian Peng
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - J Timothy Sage
- Department of Physics and Center for Interdisciplinary Research on Complex Systems , Northeastern University , Boston , Massachusetts 02115 , United States
| | - Yulong Liu
- College of Materials Science and Optoelectronic Technology , University of Chinese Academy of Sciences , Yanqi Lake, Huairou, Beijing 101408 , China
| | - Zijian Wang
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry , Nankai University , Tianjin 300071 , China
| | - Michael Y Hu
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Jiyong Zhao
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - E Ercan Alp
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - W Robert Scheidt
- Department of Chemistry and Biochemistry , University of Notre Dame , Notre Dame , Indiana 46556 , United States
| | - Jianfeng Li
- College of Materials Science and Optoelectronic Technology , University of Chinese Academy of Sciences , Yanqi Lake, Huairou, Beijing 101408 , China
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39
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Lewis RD, Garcia-Borràs M, Chalkley MJ, Buller AR, Houk KN, Kan SBJ, Arnold FH. Catalytic iron-carbene intermediate revealed in a cytochrome c carbene transferase. Proc Natl Acad Sci U S A 2018; 115:7308-7313. [PMID: 29946033 PMCID: PMC6048479 DOI: 10.1073/pnas.1807027115] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Recently, heme proteins have been discovered and engineered by directed evolution to catalyze chemical transformations that are biochemically unprecedented. Many of these nonnatural enzyme-catalyzed reactions are assumed to proceed through a catalytic iron porphyrin carbene (IPC) intermediate, although this intermediate has never been observed in a protein. Using crystallographic, spectroscopic, and computational methods, we have captured and studied a catalytic IPC intermediate in the active site of an enzyme derived from thermostable Rhodothermus marinus (Rma) cytochrome c High-resolution crystal structures and computational methods reveal how directed evolution created an active site for carbene transfer in an electron transfer protein and how the laboratory-evolved enzyme achieves perfect carbene transfer stereoselectivity by holding the catalytic IPC in a single orientation. We also discovered that the IPC in Rma cytochrome c has a singlet ground electronic state and that the protein environment uses geometrical constraints and noncovalent interactions to influence different IPC electronic states. This information helps us to understand the impressive reactivity and selectivity of carbene transfer enzymes and offers insights that will guide and inspire future engineering efforts.
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Affiliation(s)
- Russell D Lewis
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena, CA 91125
| | - Marc Garcia-Borràs
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Matthew J Chalkley
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Andrew R Buller
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - K N Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095;
| | - S B Jennifer Kan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
| | - Frances H Arnold
- Division of Biology and Bioengineering, California Institute of Technology, Pasadena, CA 91125;
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125
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40
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Postils V, Rodríguez M, Sabenya G, Conde A, Díaz-Requejo MM, Pérez PJ, Costas M, Solà M, Luis JM. Mechanism of the Selective Fe-Catalyzed Arene Carbon–Hydrogen Bond Functionalization. ACS Catal 2018. [DOI: 10.1021/acscatal.7b03935] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Verònica Postils
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
| | - Mònica Rodríguez
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
| | - Gerard Sabenya
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
| | - Ana Conde
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, 21007 Huelva, Spain
| | - M. Mar Díaz-Requejo
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, 21007 Huelva, Spain
| | - Pedro J. Pérez
- Laboratorio de Catálisis Homogénea, Unidad Asociada al CSIC, CIQSO-Centro de Investigación en Química Sostenible and Departamento de Química, Universidad de Huelva, 21007 Huelva, Spain
| | - Miquel Costas
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
| | - Miquel Solà
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
| | - Josep M. Luis
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Campus Montilivi, 17071, Girona, Spain
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41
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Wei Y, Tinoco A, Steck V, Fasan R, Zhang Y. Cyclopropanations via Heme Carbenes: Basic Mechanism and Effects of Carbene Substituent, Protein Axial Ligand, and Porphyrin Substitution. J Am Chem Soc 2018; 140:1649-1662. [PMID: 29268614 PMCID: PMC5875692 DOI: 10.1021/jacs.7b09171] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
Catalytic carbene
transfer to olefins is a useful approach to synthesize
cyclopropanes, which are key structural motifs in many drugs and biologically
active natural products. While catalytic methods for olefin cyclopropanation
have largely relied on rare transition-metal-based catalysts, recent
studies have demonstrated the promise and synthetic value of iron-based
heme-containing proteins for promoting these reactions with excellent
catalytic activity and selectivity. Despite this progress, the mechanism
of iron-porphyrin and hemoprotein-catalyzed olefin cyclopropanation
has remained largely unknown. Using a combination of quantum chemical
calculations and experimental mechanistic analyses, the present study
shows for the first time that the increasingly useful C=C functionalizations
mediated by heme carbenes feature an FeII-based, nonradical,
concerted nonsynchronous mechanism, with early transition state character.
This mechanism differs from the FeIV-based, radical, stepwise
mechanism of heme-dependent monooxygenases. Furthermore, the effects
of the carbene substituent, metal coordinating axial ligand, and porphyrin
substituent on the reactivity of the heme carbenes was systematically
investigated, providing a basis for explaining experimental reactivity
results and defining strategies for future catalyst development. Our
results especially suggest the potential value of electron-deficient
porphyrin ligands for increasing the electrophilicity and thus the
reactivity of the heme carbene. Metal-free reactions were also studied
to reveal temperature and carbene substituent effects on catalytic
vs noncatalytic reactions. This study sheds new light into the mechanism
of iron-porphyrin and hemoprotein-catalyzed cyclopropanation reactions
and it is expected to facilitate future efforts toward sustainable
carbene transfer catalysis using these systems.
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Affiliation(s)
- Yang Wei
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology , 1 Castle Point on Hudson, Hoboken, New Jersey 07030, United States of America
| | - Antonio Tinoco
- Department of Chemistry, University of Rochester , 120 Trustee Road, Rochester, New York 14627, United States of America
| | - Viktoria Steck
- Department of Chemistry, University of Rochester , 120 Trustee Road, Rochester, New York 14627, United States of America
| | - Rudi Fasan
- Department of Chemistry, University of Rochester , 120 Trustee Road, Rochester, New York 14627, United States of America
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology , 1 Castle Point on Hudson, Hoboken, New Jersey 07030, United States of America
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42
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Khade RL, Zhang Y. C-H Insertions by Iron Porphyrin Carbene: Basic Mechanism and Origin of Substrate Selectivity. Chemistry 2017; 23:17654-17658. [PMID: 29071754 DOI: 10.1002/chem.201704631] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Indexed: 11/09/2022]
Abstract
Recent experimental reports of heme carbene C-H insertions show promising results for sustainable chemistry due to good yield and selectivity, low cost of iron, and low/no toxicity of hemes. But mechanistic details are mostly unknown. Despite structural similarity and isoelectronic nature between heme carbene and the FeIV =O intermediate, our quantum chemical studies with detailed geometric and electronic information for the first time reveal an FeII -based, concerted, hydride-transfer mechanism, which is different from the FeIV -based stepwise hydrogen atom transfer mechanism for C-H functionalization by native heme enzymes. A trend of broad range experimental C-H insertion yields (0-88 %) of five different C-H bonds, including mostly non-functionalized moieties, was well reproduced. Results suggest that the substrate selectivity originates from the hydride formation capability. The predicted kinetic isotope effects were also in excellent agreement with experiment. Useful geometry, charge, and energy parameters well correlated with barriers were reported. These results provide the first theoretical evidence that carbene formation is the overall rate-limiting step, and suggest a key role of the formation of strong electrophilic heme carbene in developing heme-based C-H insertion catalysts and biocatalysts.
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Affiliation(s)
- Rahul L Khade
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point on Hudson, Hoboken, NJ 07030, USA
| | - Yong Zhang
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, 1 Castle Point on Hudson, Hoboken, NJ 07030, USA
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43
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Brandenberg OF, Fasan R, Arnold FH. Exploiting and engineering hemoproteins for abiological carbene and nitrene transfer reactions. Curr Opin Biotechnol 2017; 47:102-111. [PMID: 28711855 DOI: 10.1016/j.copbio.2017.06.005] [Citation(s) in RCA: 207] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 06/12/2017] [Indexed: 12/25/2022]
Abstract
The surge in reports of heme-dependent proteins as catalysts for abiotic, synthetically valuable carbene and nitrene transfer reactions dramatically illustrates the evolvability of the protein world and our nascent ability to exploit that for new enzyme chemistry. We highlight the latest additions to the hemoprotein-catalyzed reaction repertoire (including carbene Si-H and C-H insertions, Doyle-Kirmse reactions, aldehyde olefinations, azide-to-aldehyde conversions, and intermolecular nitrene C-H insertion) and show how different hemoprotein scaffolds offer varied reactivity and selectivity. Preparative-scale syntheses of pharmaceutically relevant compounds accomplished with these new catalysts are beginning to demonstrate their biotechnological relevance. Insights into the determinants of enzyme lifetime and product yield are providing generalizable cues for engineering heme-dependent proteins to further broaden the scope and utility of these non-natural activities.
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Affiliation(s)
- Oliver F Brandenberg
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Blvd, Pasadena, CA 91125, USA
| | - Rudi Fasan
- Department of Chemistry, University of Rochester, Hutchison Hall, 120 Trustee Rd, Rochester, NY 14627, USA.
| | - Frances H Arnold
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Blvd, Pasadena, CA 91125, USA.
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44
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Liu Y, Xu W, Zhang J, Fuller W, Schulz CE, Li J. Electronic Configuration and Ligand Nature of Five-Coordinate Iron Porphyrin Carbene Complexes: An Experimental Study. J Am Chem Soc 2017; 139:5023-5026. [PMID: 28339195 DOI: 10.1021/jacs.7b01722] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The five-coordinate iron porphyrin carbene complexes [Fe(TPP) (CCl2)] (TPP = tetraphenylporphyrin), [Fe(TTP) (CCl2)] (TTP = tetratolylporphyrin) and [Fe(TFPP) (CPh2)] (TFPP = tetra(pentafluorophenyl)porphyrin), utilizing two types of carbene ligands (CCl2 and CPh2), have been investigated by single crystal X-ray, XANES (X-ray absorption near edge spectroscopy), Mössbauer, NMR and UV-vis spectroscopies. The XANES suggested the iron(II) oxidation state of the complexes. The multitemperature and high magnetic field Mössbauer experiments, which show very large quadrupole splittings (QS, ΔEQ), determined the S = 0 electronic configuration. More importantly, combined structural and Mössbauer studies, especially the comparison with the low spin iron(II) porphyrin complexes with strong diatomic ligands (CS, CO and CN-) revealed the covalent bond nature of the carbene ligands. A correlation between the iron isomer shifts (IS, δ) and the axial bond distances is established for the first time for these donor carbon ligands (:C-R).
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Affiliation(s)
- Yulong Liu
- College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences , Yanqi Lake, Huairou District, Beijing 101408, China
| | - Wei Xu
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, China
| | - Jing Zhang
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences , Beijing 100049, China
| | - William Fuller
- Department of Physics, Knox College , Galesburg, Illinois 61401, United States
| | - Charles E Schulz
- Department of Physics, Knox College , Galesburg, Illinois 61401, United States
| | - Jianfeng Li
- College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences , Yanqi Lake, Huairou District, Beijing 101408, China
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45
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Liu J, Hu L, Wang L, Chen H, Deng L. An Iron(II) Ylide Complex as a Masked Open-Shell Iron Alkylidene Species in Its Alkylidene-Transfer Reactions with Alkenes. J Am Chem Soc 2017; 139:3876-3888. [DOI: 10.1021/jacs.7b00484] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jian Liu
- State
Key Laboratory of Organometallic Chemistry, Shanghai Institute of
Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China
| | - Lianrui Hu
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Lei Wang
- State
Key Laboratory of Organometallic Chemistry, Shanghai Institute of
Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China
| | - Hui Chen
- Beijing
National Laboratory for Molecular Sciences, CAS Key Laboratory of
Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
| | - Liang Deng
- State
Key Laboratory of Organometallic Chemistry, Shanghai Institute of
Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, P. R. China
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46
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Upp DM, Lewis JC. Selective C-H bond functionalization using repurposed or artificial metalloenzymes. Curr Opin Chem Biol 2017; 37:48-55. [PMID: 28135654 DOI: 10.1016/j.cbpa.2016.12.027] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 12/23/2016] [Indexed: 11/26/2022]
Abstract
Catalytic CH bond functionalization has become an important tool for organic synthesis. Metalloenzymes offer a solution to one of the foremost challenges in this field, site-selective CH functionalization, but they are only capable of catalyzing a subset of the CH functionalization reactions known to small molecule catalysts. To overcome this limitation, metalloenzymes have been repurposed by exploiting the reactivity of their native cofactors toward substrates not found in nature. Additionally, new reactivity has been accessed by incorporating synthetic metal cofactors into protein scaffolds to form artificial metalloenzymes. The selectivity and activity of these catalysts has been tuned using directed evolution. This review covers the recent progress in developing and optimizing both repurposed and artificial metalloenzymes as catalysts for selective CH bond functionalization.
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Affiliation(s)
- David M Upp
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA
| | - Jared C Lewis
- Department of Chemistry, University of Chicago, Chicago, IL 60637, USA.
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47
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Carminati DM, Intrieri D, Le Gac S, Roisnel T, Boitrel B, Toma L, Legnani L, Gallo E. Synthesis, characterisation and catalytic use of iron porphyrin amino ester conjugates. NEW J CHEM 2017. [DOI: 10.1039/c7nj01189j] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This study described the synthesis and characterisation of C2-symmetrical chiral Fe(iii)(porphyrin)(OMe) complexes, whose activity as cyclopropanation catalysts was investigated from both experimental and theoretical viewpoints.
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Affiliation(s)
| | | | - Stéphane Le Gac
- Institut des Sciences Chimiques de Rennes
- Université de Rennes 1
- 35042 Rennes Cedex
- France
| | - Thierry Roisnel
- Institut des Sciences Chimiques de Rennes
- Université de Rennes 1
- 35042 Rennes Cedex
- France
| | - Bernard Boitrel
- Institut des Sciences Chimiques de Rennes
- Université de Rennes 1
- 35042 Rennes Cedex
- France
| | - Lucio Toma
- Department of Chemistry
- University of Pavia
- 27100 Pavia
- Italy
| | - Laura Legnani
- Department of Chemistry
- University of Pavia
- 27100 Pavia
- Italy
| | - Emma Gallo
- Department of Chemistry
- University of Milan
- 20133 Milan
- Italy
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48
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Tyagi V, Sreenilayam G, Bajaj P, Tinoco A, Fasan R. Biocatalytic Synthesis of Allylic and Allenyl Sulfides through a Myoglobin-Catalyzed Doyle-Kirmse Reaction. Angew Chem Int Ed Engl 2016; 55:13562-13566. [PMID: 27647732 PMCID: PMC5189672 DOI: 10.1002/anie.201607278] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Indexed: 11/11/2022]
Abstract
The first example of a biocatalytic [2,3]-sigmatropic rearrangement reaction involving allylic sulfides and diazo reagents (Doyle-Kirmse reaction) is reported. Engineered variants of sperm whale myoglobin catalyze this synthetically valuable C-C bond-forming transformation with high efficiency and product conversions across a variety of sulfide substrates (e.g., aryl-, benzyl-, and alkyl-substituted allylic sulfides) and α-diazo esters. Moreover, the scope of this myoglobin-mediated transformation could be extended to the conversion of propargylic sulfides to give substituted allenes. Active-site mutations proved effective in enhancing the catalytic efficiency of the hemoprotein in these reactions as well as modulating the enantioselectivity, resulting in the identification of the myoglobin variant Mb(L29S,H64V,V68F), which is capable of mediating asymmetric Doyle-Kirmse reactions with an enantiomeric excess up to 71 %. This work extends the toolbox of currently available biocatalytic strategies for the asymmetric formation of carbon-carbon bonds.
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Affiliation(s)
- Vikas Tyagi
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY, 14627, USA
| | | | - Priyanka Bajaj
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY, 14627, USA
| | - Antonio Tinoco
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY, 14627, USA
| | - Rudi Fasan
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY, 14627, USA.
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49
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Tyagi V, Sreenilayam G, Bajaj P, Tinoco A, Fasan R. Biocatalytic Synthesis of Allylic and Allenyl Sulfides through a Myoglobin-Catalyzed Doyle-Kirmse Reaction. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201607278] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Vikas Tyagi
- Department of Chemistry; University of Rochester; 120 Trustee Road Rochester NY 14627 USA
| | | | - Priyanka Bajaj
- Department of Chemistry; University of Rochester; 120 Trustee Road Rochester NY 14627 USA
| | - Antonio Tinoco
- Department of Chemistry; University of Rochester; 120 Trustee Road Rochester NY 14627 USA
| | - Rudi Fasan
- Department of Chemistry; University of Rochester; 120 Trustee Road Rochester NY 14627 USA
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50
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Renata H, Lewis RD, Sweredoski MJ, Moradian A, Hess S, Wang ZJ, Arnold FH. Identification of Mechanism-Based Inactivation in P450-Catalyzed Cyclopropanation Facilitates Engineering of Improved Enzymes. J Am Chem Soc 2016; 138:12527-33. [PMID: 27573353 DOI: 10.1021/jacs.6b06823] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Following the recent discovery that heme proteins can catalyze the cyclopropanation of styrenyl olefins with high efficiency and selectivity, interest in developing new enzymes for a variety of non-natural carbene transfer reactions has burgeoned. The fact that diazo compounds and other carbene precursors are known mechanism-based inhibitors of P450s, however, led us to investigate if they also interfere with this new enzyme function. We present evidence for two inactivation pathways that are operative during cytochrome P450-catalyzed cyclopropanation. Using a combination of UV-vis, mass spectrometry, and proteomic analyses, we show that the heme cofactor and several nucleophilic side chains undergo covalent modification by ethyl diazoacetate (EDA). Substitution of two of the affected residues with less-nucleophilic amino acids led to a more than twofold improvement in cyclopropanation performance (total TTN). Elucidating the inactivation pathways of heme protein-based carbene transfer catalysts should aid in the optimization of this new biocatalytic function.
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Affiliation(s)
- Hans Renata
- Division of Chemistry and Chemical Engineering, MC 210-41, and ‡Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman Institute, MC 139-74, California Institute of Technology , 1200 E California Blvd, Pasadena, California 91125, United States
| | - Russell D Lewis
- Division of Chemistry and Chemical Engineering, MC 210-41, and ‡Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman Institute, MC 139-74, California Institute of Technology , 1200 E California Blvd, Pasadena, California 91125, United States
| | - Michael J Sweredoski
- Division of Chemistry and Chemical Engineering, MC 210-41, and ‡Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman Institute, MC 139-74, California Institute of Technology , 1200 E California Blvd, Pasadena, California 91125, United States
| | - Annie Moradian
- Division of Chemistry and Chemical Engineering, MC 210-41, and ‡Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman Institute, MC 139-74, California Institute of Technology , 1200 E California Blvd, Pasadena, California 91125, United States
| | - Sonja Hess
- Division of Chemistry and Chemical Engineering, MC 210-41, and ‡Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman Institute, MC 139-74, California Institute of Technology , 1200 E California Blvd, Pasadena, California 91125, United States
| | - Z Jane Wang
- Division of Chemistry and Chemical Engineering, MC 210-41, and ‡Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman Institute, MC 139-74, California Institute of Technology , 1200 E California Blvd, Pasadena, California 91125, United States
| | - Frances H Arnold
- Division of Chemistry and Chemical Engineering, MC 210-41, and ‡Proteome Exploration Laboratory, Division of Biology and Biological Engineering, Beckman Institute, MC 139-74, California Institute of Technology , 1200 E California Blvd, Pasadena, California 91125, United States
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