1
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Tsien J, Hu C, Merchant RR, Qin T. Three-dimensional saturated C(sp 3)-rich bioisosteres for benzene. Nat Rev Chem 2024:10.1038/s41570-024-00623-0. [PMID: 38982260 DOI: 10.1038/s41570-024-00623-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2024] [Indexed: 07/11/2024]
Abstract
Benzenes, the most ubiquitous structural moiety in marketed small-molecule drugs, are frequently associated with poor 'drug-like' properties, including metabolic instability, and poor aqueous solubility. In an effort to overcome these limitations, recent developments in medicinal chemistry have demonstrated the improved physicochemical profiles of C(sp3)-rich bioisosteric scaffolds relative to arenes. In the past two decades, we have witnessed an exponential increase in synthetic methods for accessing saturated bioisosteres of monosubstituted and para-substituted benzenes. However, until recent discoveries, analogous three-dimensional ortho-substituted and meta-substituted biososteres have remained underexplored, owing to their ring strain and increased s-character hybridization. This Review summarizes the emerging synthetic methodologies to access such saturated motifs and their impact on the application of bioisosteres for ortho-substituted, meta-substituted and multi-substituted benzene rings. It concludes with a perspective on the development of next-generation bioisosteres, including those within novel chemical space.
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Affiliation(s)
- Jet Tsien
- Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Chao Hu
- Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Rohan R Merchant
- Department of Discovery Chemistry, Merck & Co., Inc., South San Francisco, CA, USA
| | - Tian Qin
- Department of Biochemistry, The University of Texas Southwestern Medical Center, Dallas, TX, USA.
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2
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Kubo M, Yamaguchi J. Divergent Transformations of Aromatic Esters: Decarbonylative Coupling, Ester Dance, Aryl Exchange, and Deoxygenative Coupling. Acc Chem Res 2024; 57:1747-1760. [PMID: 38819671 PMCID: PMC11191398 DOI: 10.1021/acs.accounts.4c00233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 05/18/2024] [Accepted: 05/21/2024] [Indexed: 06/01/2024]
Abstract
ConspectusAromatic esters are cost-effective, versatile, and commonly used scaffolds that are readily synthesized or encountered as synthetic intermediates. While most conventional reactions involving these esters are nucleophilic acyl substitutions or 1,2-nucleophilic additions─where a nucleophile attacks the carbonyl group, decarbonylative transformations offer an alternative pathway by using the carbonyl group as a leaving group. This transition-metal-catalyzed process typically begins with oxidative addition of the C(acyl)-O bond to the metal. Subsequently, the reaction involves the migration of CO to the metal center, the reaction with a nucleophile, and reductive elimination to yield the final product. Pioneering work by Yamamoto on nickel complexes and the development of decarbonylative reactions (such as Mizoroki-Heck-type olefination) using aromatic carboxylic anhydrides catalyzed by palladium were conducted by de Vries and Stephan. Furthermore, reports have surfaced of decarbonylative hydrogenation of pyridyl methyl esters by Murai using ruthenium catalysts as well as Mizoroki-Heck-type reactions of nitro phenyl esters by Gooßen under palladium catalysis. Our group has been at the forefront of developing decarbonylative C-H arylations of phenyl esters with 1,3-azoles and aryl boronic acids using nickel catalysts. The key to this reaction is the use of phenyl esters, which are easy to synthesize, stabilize, and handle, allowing oxidative addition of the C(acyl)-O bond; nickel, which facilitates oxidative addition of the C(acyl)-O bond; and suitable bidentate phosphine ligands that can stabilize the intermediate. By modification of the nucleophiles, esters have been effectively utilized as electrophiles in cross-coupling reactions, encouraging the development of these nucleophiles among researchers. This Account summarizes our advancements in nucleophile development for decarbonylative coupling reactions, particularly highlighting the utilization of aromatic esters in diverse reactions such as alkenylation, intramolecular etherification, α-arylation of ketones, C-H arylation, methylation, and intramolecular C-H arylation for dibenzofuran synthesis, along with cyanation and reductive coupling. We also delve into reaction types that are distinct from typical decarbonylative reactions, including ester dance reactions, aromatic ring exchanges, and deoxygenative transformations, by focusing on the oxidative addition of the C(acyl)-O bond of the aromatic esters to the metal complex. For example, the ester dance reaction is hypothesized to undergo 1,2-translocation starting with oxidative addition to a palladium complex, leading to a sequence of ortho-deprotonation/decarbonylation, followed by protonation, carbonylation, and reductive elimination. The aromatic exchange reaction likely involves oxidative addition of complexes of different aryl electrophiles with a nickel complex. In deoxygenative coupling, an oxidative addition complex with palladium engages with a nucleophile, forming an acyl intermediate that undergoes reductive elimination in the presence of an appropriate reducing agent. These methodologies are poised to captivate the interest of synthetic chemists by offering unconventional and emerging approaches for transforming aromatic esters. Moreover, we demonstrated the potential to transform readily available basic chemicals into new compounds through organic synthesis.
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Affiliation(s)
- Masayuki Kubo
- Department of Applied Chemistry, Waseda University, 513 Wasedatsurumakicho, Shinjuku, Tokyo 162-0041, Japan
| | - Junichiro Yamaguchi
- Department of Applied Chemistry, Waseda University, 513 Wasedatsurumakicho, Shinjuku, Tokyo 162-0041, Japan
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3
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Sun D, Gong Y, Wu Y, Chen Y, Gong H. Bis(pinacolato)diboron-Enabled Ni-Catalyzed Reductive Arylation/Vinylation of Alkyl Electrophiles. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024:e2404301. [PMID: 38887210 DOI: 10.1002/advs.202404301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Indexed: 06/20/2024]
Abstract
Herein, the use of economically and environmentally friendly bis(pinacolato)diboron (B2Pin2) is described as a non-metallic reductant in mediating Ni-catalyzed C(sp3)-C(sp2) reductive cross-coupling of alkyl electrophiles with aryl/vinyl halides. This method exhibits excellent suitability for heteroaryl halides and alkyl halides/Katritzky salts. The present study is compatible with an in situ halogenation of alcohol method, allowing for selective mono-functionalization of diols and bio-relevant alcohols (e.g., carbohydrates). The use of B2Pin2 shows potential for easy scalability without introducing additional metal impurities into the products. It is observed for the first time in the realm of cross-electrophile coupling chemistry that B2Pin2 can sever as a reductant to reduce NiII to Ni0. This mechanistic insight may inspire the development of new reductive bond-forming methodologies that can otherwise be difficult to achieve with a metal reductant.
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Affiliation(s)
- Deli Sun
- School of Resources and Environmental Engineering, Shanghai Polytechnic University, No. 2360 Jinhai Road, Shanghai, 201209, China
| | - Yuxin Gong
- Center for Supramolecular Chemistry and Catalysis, Department of Chemistry, Shanghai University, Shanghai, 200444, China
| | - Yu Wu
- Center for Supramolecular Chemistry and Catalysis, Department of Chemistry, Shanghai University, Shanghai, 200444, China
| | - Yunrong Chen
- Center for Supramolecular Chemistry and Catalysis, Department of Chemistry, Shanghai University, Shanghai, 200444, China
| | - Hegui Gong
- Center for Supramolecular Chemistry and Catalysis, Department of Chemistry, Shanghai University, Shanghai, 200444, China
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4
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Lukas F, Findlay MT, Fillols M, Templ J, Savino E, Martin B, Allmendinger S, Furegati M, Noël T. Graphitic Carbon Nitride as a Photocatalyst for Decarboxylative C(sp 2)-C(sp 3) Couplings via Nickel Catalysis. Angew Chem Int Ed Engl 2024:e202405902. [PMID: 38807439 DOI: 10.1002/anie.202405902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 05/17/2024] [Accepted: 05/22/2024] [Indexed: 05/30/2024]
Abstract
The development of robust and reliable methods for the construction of C(sp2)-C(sp3) bonds is vital for accessing an increased array of structurally diverse scaffolds in drug discovery and development campaigns. While significant advances towards this goal have been achieved using metallaphotoredox chemistry, many of these methods utilise photocatalysts based on precious-metals due to their efficient redox processes and tuneable properties. However, due to the cost, scarcity, and toxicity of these metals, the search for suitable replacements should be a priority. Here, we show the use of commercially available heterogeneous semiconductor graphitic carbon nitride (gCN) as a photocatalyst, combined with nickel catalysis, for the cross-coupling between aryl halide and carboxylic acid coupling partners. gCN has been shown to engage in single-electron-transfer (SET) and energy-transfer (EnT) processes for the formation of C-X bonds, and in this manuscript we overcome previous limitations to furnish C-C over C-O bonds using carboxylic acids. A broad scope of both aryl halides and carboxylic acids is presented, and recycling of the photocatalyst demonstrated. The mechanism of the reaction is also investigated.
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Affiliation(s)
- Florian Lukas
- Flow Chemistry Group, Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Michael T Findlay
- Flow Chemistry Group, Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Méritxell Fillols
- Flow Chemistry Group, Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | - Johanna Templ
- Flow Chemistry Group, Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/E163, 1060, Vienna, Austria
| | - Elia Savino
- Flow Chemistry Group, Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
| | | | | | | | - Timothy Noël
- Flow Chemistry Group, Van't Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
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5
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Yu Q, Zhou D, Ma J, Song C. Decarboxylative Nucleophilic Fluorination of Aliphatic Carboxylic Acids. Org Lett 2024; 26:4257-4261. [PMID: 38738813 DOI: 10.1021/acs.orglett.4c01185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
Herein, we present a decarboxylative nucleophilic fluorination of carboxylic acids with a silver catalyst. This strategy enables the synthesis of a myriad of diverse and valuable fluorinated motifs under mild conditions, demonstrating good functional-group tolerance and utility in late-stage functionalization. In contrast to traditional electrophilic fluorination, this nucleophilic method utilizes a more readily available nucleophilic fluorinating reagent, providing substantial advantages in terms of cost efficiency, broad substrate scope, and functional-group compatibility.
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Affiliation(s)
- Qian Yu
- College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Donglin Zhou
- College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Junjun Ma
- College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
| | - Chunlan Song
- College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, China
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6
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Chheda PR, Simmons N, Shi Z. Hydrophobic Surfactant-DNA Complex (Surf-DNA) Enables DNA-Encoded-Library-Compatible Decarboxylative Arylation under Anhydrous Conditions. Org Lett 2024; 26:4365-4370. [PMID: 38743933 DOI: 10.1021/acs.orglett.4c01398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
DNA-encoded libraries (DELs) are a key technology for identifying small-molecule hits in both the pharmaceutical industry and academia, but their chemical diversity is largely limited to water-compatible reactions to aid in the solubility and integrity of encoding DNA tags. To broaden the DEL chemical space, we present a workflow utilizing DNA-cationic surfactant complexation that enables dissolution and reactions on-DNA in anhydrous organic solvents. We demonstrate its utility by developing DEL-compatible photoredox decarboxylative C(sp2)-C(sp3) coupling under water-free conditions. The workflow is optimized for the 96-well format necessary for large-scale DEL productions, and it enables screening and optimization of DEL-compatible reactions in organic solvents.
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Affiliation(s)
- Pratik R Chheda
- Discovery Chemistry, Janssen Research & Development, LLC, San Diego, California 92121, United States
| | - Nicholas Simmons
- Discovery Chemistry, Janssen Research & Development, LLC, San Diego, California 92121, United States
| | - Zhicai Shi
- Discovery Chemistry, Janssen Research & Development, LLC, Spring House, Pennsylvania 19477, United States
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7
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Kweon J, Park B, Kim D, Chang S. Decarboxylative stereoretentive C-N coupling by harnessing aminating reagent. Nat Commun 2024; 15:3788. [PMID: 38710673 DOI: 10.1038/s41467-024-48075-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/15/2024] [Indexed: 05/08/2024] Open
Abstract
In recent decades, strategies involving transition-metal catalyzed carbon-carbon or carbon-heteroatom bond coupling have emerged as potent synthetic tools for constructing intricate molecular architectures. Among these, decarboxylative carbon-nitrogen bond formation using abundant carboxylic acids or their derivatives has garnered notable attention for accessing alkyl- or arylamines, one of key pharmacophores. While several decarboxylative amination methods have been developed, the involvement of a common carboradical intermediate currently poses challenges in achieving stereospecific transformation toward chiral alkylamines. Herein, we present a base-mediated, stereoretentive decarboxylative amidation by harnessing 1,4,2-dioxazol-5-one as a reactive and robust amidating reagent under transition-metal-free ambient conditions, encompassing all types of primary, secondary and tertiary carboxylic acids, thereby providing access to the important pharmacophore, α-chiral amines. This method exhibits high functional group tolerance, convenient scalability, and ease of applicability for 15N-isotope labeling, thus accentuating its synthetic utilities. Experimental and computational mechanistic investigations reveal a sequence of elementary steps: i) nucleophilic addition of carboxylate to dioxazolone, ii) rearrangement to form a dicarbonyl N-hydroxy intermediate, iii) conversion to hydroxamate, followed by a Lossen-type rearrangement, and finally, iv) reaction of the in situ generated isocyanate with carboxylate leading to C-N bond formation in a stereoretentive manner.
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Affiliation(s)
- Jeonguk Kweon
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, South Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Bumsu Park
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Dongwook Kim
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, South Korea
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea
| | - Sukbok Chang
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon, 34141, South Korea.
- Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, South Korea.
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8
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Mills LR, Simmons EM, Lee H, Nester E, Kim J, Wisniewski SR, Pecoraro MV, Chirik PJ. (Phenoxyimine)nickel-Catalyzed C(sp 2)-C(sp 3) Suzuki-Miyaura Cross-Coupling: Evidence for a Recovering Radical Chain Mechanism. J Am Chem Soc 2024; 146:10124-10141. [PMID: 38557045 DOI: 10.1021/jacs.4c01474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Phenoxyimine (FI)-nickel(II)(2-tolyl)(DMAP) compounds were synthesized and evaluated as precatalysts for the C(sp2)-C(sp3) Suzuki-Miyaura cross coupling of (hetero)arylboronic acids with alkyl bromides. With 5 mol % of the optimal (MeOMeFI)Ni(Aryl)(DMAP) precatalyst, the scope of the cross-coupling reaction was established and included a variety of (hetero)arylboronic acids and alkyl bromides (>50 examples, 33-97% yield). A β-hydride elimination-reductive elimination sequence from reaction with potassium isopropoxide base, yielding a potassium (FI)nickel(0)ate, was identified as a catalyst activation pathway that is responsible for halogen atom abstraction from the alkyl bromide. A combination of NMR and EPR spectroscopies identified (FI)nickel(II)-aryl complexes as the resting state during catalysis with no evidence for long-lived organic radical or odd-electron nickel intermediates. These data establish that the radical chain is short-lived and undergoes facile termination and also support a "recovering radical chain" process whereby the (FI)nickel(II)-aryl compound continually (re)initiates the radical chain. Kinetic studies established that the rate of C(sp2)-C(sp3) product formation was proportional to the concentration of the (FI)nickel(II)-aryl resting state that captures the alkyl radical for chain propagation. The proposed mechanism involves two key and concurrently operating catalytic cycles; the first involving a nickel(I/II/III) radical propagation cycle consisting of radical capture at (FI)nickel(II)-aryl, C(sp2)-C(sp3) reductive elimination, bromine atom abstraction from C(sp3)-Br, and transmetalation; and the second involving an off-cycle catalyst recovery process by slow (FI)nickel(II)-aryl → (FI)nickel(0)ate conversion for nickel(I) regeneration.
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Affiliation(s)
- L Reginald Mills
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Eric M Simmons
- Chemical Process Development, Bristol Myers Squibb Company, New Brunswick, New Jersey 08903, United States
| | - Heejun Lee
- Chemical Process Development, Bristol Myers Squibb Company, New Brunswick, New Jersey 08903, United States
| | - Eva Nester
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Junho Kim
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Steven R Wisniewski
- Chemical Process Development, Bristol Myers Squibb Company, New Brunswick, New Jersey 08903, United States
| | - Matthew V Pecoraro
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
| | - Paul J Chirik
- Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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9
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Chen R, Intermaggio NE, Xie J, Rossi-Ashton JA, Gould CA, Martin RT, Alcázar J, MacMillan DWC. Alcohol-alcohol cross-coupling enabled by S H2 radical sorting. Science 2024; 383:1350-1357. [PMID: 38513032 DOI: 10.1126/science.adl5890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 02/15/2024] [Indexed: 03/23/2024]
Abstract
Alcohols represent a functional group class with unparalleled abundance and structural diversity. In an era of chemical synthesis that prioritizes reducing time to target and maximizing exploration of chemical space, harnessing these building blocks for carbon-carbon bond-forming reactions is a key goal in organic chemistry. In particular, leveraging a single activation mode to form a new C(sp3)-C(sp3) bond from two alcohol subunits would enable access to an extraordinary level of structural diversity. In this work, we report a nickel radical sorting-mediated cross-alcohol coupling wherein two alcohol fragments are deoxygenated and coupled in one reaction vessel, open to air.
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Affiliation(s)
- Ruizhe Chen
- Merck Center for Catalysis at Princeton University, Princeton, NJ 08544, USA
| | | | - Jiaxin Xie
- Merck Center for Catalysis at Princeton University, Princeton, NJ 08544, USA
| | | | - Colin A Gould
- Merck Center for Catalysis at Princeton University, Princeton, NJ 08544, USA
| | - Robert T Martin
- Merck Center for Catalysis at Princeton University, Princeton, NJ 08544, USA
| | - Jesús Alcázar
- Discovery Chemistry, Janssen Research and Development, Janssen-Cilag, S.A., C/Jarama 75A, 45007 Toledo, Spain
| | - David W C MacMillan
- Merck Center for Catalysis at Princeton University, Princeton, NJ 08544, USA
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10
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Laudadio G, Neigenfind P, Chebolu R, Blasczak VD, Maddirala SJ, Palkowitz MD, Bolduc PN, Nicastri MC, Puthukanoori RK, Paraselli BR, Baran PS. Synthesis of Unnatural Amino Acids via Ni/Ag Electrocatalytic Cross-Coupling. Org Lett 2024; 26:2276-2281. [PMID: 38467055 DOI: 10.1021/acs.orglett.4c00474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/13/2024]
Abstract
A simple protocol is outlined herein for rapid access to enantiopure unnatural amino acids (UAAs) from trivial glutamate and aspartate precursors. The method relies on Ag/Ni-electrocatalytic decarboxylative coupling and can be rapidly conducted in parallel (24 reactions at a time) to ascertain coupling viability followed by scale-up for the generation of useful quantities of UAAs for exploratory studies.
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Affiliation(s)
- Gabriele Laudadio
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Philipp Neigenfind
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Rajesh Chebolu
- Chemveda Life Sciences Pvt Ltd., Plot. No. B-11/1, IDA Uppal, Hyderabad, Telangana 500039, India
| | - Vanna D Blasczak
- Biogen Inc., 225 Binney Street, Cambridge, Massachusetts 02142, United States
| | | | - Maximilian D Palkowitz
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Philippe N Bolduc
- Biogen Inc., 225 Binney Street, Cambridge, Massachusetts 02142, United States
| | - Michael C Nicastri
- Biogen Inc., 225 Binney Street, Cambridge, Massachusetts 02142, United States
| | - Ravi Kumar Puthukanoori
- Chemveda Life Sciences Pvt Ltd., Plot. No. B-11/1, IDA Uppal, Hyderabad, Telangana 500039, India
| | - Bheema Rao Paraselli
- Chemveda Life Sciences Pvt Ltd., Plot. No. B-11/1, IDA Uppal, Hyderabad, Telangana 500039, India
- Chemveda Life Sciences, Inc., 9920 Pacific Heights Blvd. Suite 150, San Diego, California 92121, United States
| | - Phil S Baran
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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11
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Sun J, Endo H, Emmanuel MA, Oderinde MS, Kawamata Y, Baran PS. Simplified Modular Access to Enantiopure 1,2-Aminoalcohols via Ni-Electrocatalytic Decarboxylative Arylation. J Am Chem Soc 2024; 146:6209-6216. [PMID: 38387466 PMCID: PMC10962872 DOI: 10.1021/jacs.3c14119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 02/01/2024] [Accepted: 02/06/2024] [Indexed: 02/24/2024]
Abstract
Chiral aminoalcohols are omnipresent in bioactive compounds. Conventional strategies to access this motif involve multiple-step reactions to install the requisite functionalities stereoselectively using conventional polar bond analysis. This study reveals that a simple chiral oxazolidine-based carboxylic acid can be readily transformed to substituted chiral aminoalcohols with high stereochemical control by Ni-electrocatalytic decarboxylative arylation. This general, robust, and scalable coupling can be used to synthesize a variety of medicinally important compounds, avoiding protecting and functional group manipulations, thereby dramatically simplifying their preparation.
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Affiliation(s)
- Jiawei Sun
- Department
of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Hirofumi Endo
- Department
of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Megan A. Emmanuel
- Chemical
Process Development, Bristol Myers Squibb, 1 Squibb Drive, New Brunswick, New Jersey 08901, United States
| | - Martins S. Oderinde
- Small
Molecule Drug Discovery, Bristol Myers Squibb
Research & Early Development, Route 206 & Province Line Road, Princeton, New Jersey 08543, United States
| | - Yu Kawamata
- Department
of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Phil S. Baran
- Department
of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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12
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Chen LM, Reisman SE. Enantioselective C(sp 2)-C(sp 3) Bond Construction by Ni Catalysis. Acc Chem Res 2024; 57:751-762. [PMID: 38346006 PMCID: PMC10918837 DOI: 10.1021/acs.accounts.3c00775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 01/10/2024] [Accepted: 01/16/2024] [Indexed: 03/06/2024]
Abstract
ConspectusAfter decades of palladium dominating the realm of transition-metal-catalyzed cross-coupling, recent years have witnessed exciting advances in the development of new nickel-catalyzed cross-coupling reactions to form C(sp3) centers. Nickel possesses distinct properties compared with palladium, such as facile single-electron transfer to C(sp3) electrophiles and rapid C-C reductive elimination from NiIII. These properties, among others, make nickel particularly well-suited for reductive cross-coupling (RCC) in which two electrophiles are coupled and an exogenous reductant is used to turn over the metal catalyst. Ni-catalyzed RCCs use readily available and stable electrophiles as starting materials and exhibit good functional group tolerance, which makes them appealing for applications in the synthesis of complex molecules. Building upon the foundational work in Ni-catalyzed RCCs by the groups of Kumada, Durandetti, Weix, and others, as well as the advancements in Ni-catalyzed enantioselective redox-neutral cross-couplings led by Fu and co-workers, we initiated a program to explore the feasibility of developing highly enantioselective Ni-catalyzed RCCs. Our research has also been driven by a keen interest in unraveling the factors contributing to enantioinduction and electrophile activation as we seek new avenues for advancing our understanding and further developing these reactions.In the first part of this Account, we organize our reported methods on the basis of the identity of the C(sp3) electrophiles, including benzylic chlorides, N-hydroxyphthalimide (NHP) esters, and α-chloro esters and nitriles. We highlight how the selection of specific chiral ligands plays a pivotal role in achieving high cross-selectivity and enantioselectivity. In addition, we show that reduction can be accomplished not only with heterogeneous reductants, such as Mn0, but also with the soluble organic reductant tetrakis(dimethylamino)ethylene (TDAE), as well as electrochemically. The use of homogeneous reductants, such as TDAE, is well suited for studying the mechanism of the transformation. Although this Account primarily focuses on RCCs, we also highlight our work using trifluoroborate (BF3K) salts as radical precursors for enantioselective dual-Ni/photoredox systems.At the end of this Account, we summarize the relevant mechanistic studies of two closely related asymmetric reductive alkenylation reactions developed in our laboratory and provide a context between our work and related mechanistic studies by others. We discuss how the ligand properties influence the rates and mechanisms of electrophile activation and how understanding the mode of C(sp3) radical generation can be used to optimize the yield of an RCC. Our research endeavors to offer insights on the intricate mechanisms at play in asymmetric Ni-catalyzed RCCs with the goal of using the rate of electrophile activation to improve the substrate scope of enantioselective RCCs. We anticipate that the insights we share in this Account can provide guidance for the development of new methods in this field.
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Affiliation(s)
- Li-Ming Chen
- The
Warren and Katharine Schlinger Laboratory for Chemistry and Chemical
Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Sarah E. Reisman
- The
Warren and Katharine Schlinger Laboratory for Chemistry and Chemical
Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
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13
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Wang T, Guan Y, Zhang T, Liang Y. Ligand Relay for Nickel-Catalyzed Decarbonylative Alkylation of Aroyl Chlorides. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2306923. [PMID: 38088530 PMCID: PMC10916626 DOI: 10.1002/advs.202306923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/26/2023] [Indexed: 03/07/2024]
Abstract
Transition metal-catalyzed direct decarboxylative transformations of aromatic carboxylic acids usually require high temperatures, which limit the substrate's scope, especially for late-stage applications. The development of the selective decarbonylative of carboxylic acid derivatives, especially the most fundamental aroyl chlorides, with stable and cheap electrophiles under mild conditions is highly desirable and meaningful, but remains challenging. Herein, a strategy of nickel-catalyzed decarbonylative alkylation of aroyl chlorides via phosphine/nitrogen ligand relay is reported. The simple phosphine ligand is found essential for the decarbonylation step, while the nitrogen ligand promotes the cross-electrophile coupling. Such a ligand relay system can effectively and orderly carry out the catalytic process at room temperature, utilizing easily available aroyl chlorides as an aryl electrophile for reductive alkylation. This discovery provides a new strategy for direct decarbonylative coupling, features operationally simple, mild conditions, and excellent functional group tolerance. The mild approach is applied to the late-stage methylation of various pharmaceuticals. Extensive experiments are carried out to provide insights into the reaction pathway and support the ligand relay process.
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Affiliation(s)
- Tian‐Zhang Wang
- School of Chemistry and Chemical EngineeringShandong UniversityJinan250100China
| | - Yu‐Qiu Guan
- School of Chemistry and Chemical EngineeringShandong UniversityJinan250100China
| | - Tian‐Yu Zhang
- School of Chemistry and Chemical EngineeringShandong UniversityJinan250100China
| | - Yu‐Feng Liang
- School of Chemistry and Chemical EngineeringShandong UniversityJinan250100China
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14
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Pavlovic B, Heubel C, Kurz M, Oehl E, Waldvogel SR, Méndez M, Ruf S. Single step synthesis of β- and γ- aryl-substituted ß- and γ-amino acid derivatives by electrochemistry. Bioorg Med Chem Lett 2024; 100:129614. [PMID: 38199329 DOI: 10.1016/j.bmcl.2024.129614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 12/18/2023] [Accepted: 01/06/2024] [Indexed: 01/12/2024]
Abstract
Electrochemical transformations are a subject of increasing interest in early drug discovery due to its ability to assemble complex scaffolds under rather mild reaction conditions. In this context, we became interested in electrochemical decarboxylative cross-coupling (DCC) protocols of redox-active esters (RAEs) and halo(hetero)arenes. Starting with the one-step electrochemical synthesis of novel methylamino-substituted heterocycles we recognized the potential of this methodology to deliver a novel approach to β- and γ- amino acids by starting from the corresponding RAEs. Our work finally resulted in the delivery of novel and highly valuable trifunctional building blocks based on ß- and γ-amino-acid scaffolds.
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15
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Azpilcueta-Nicolas CR, Lumb JP. Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters. Beilstein J Org Chem 2024; 20:346-378. [PMID: 38410775 PMCID: PMC10896223 DOI: 10.3762/bjoc.20.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 01/29/2024] [Indexed: 02/28/2024] Open
Abstract
Due to their ease of preparation, stability, and diverse reactivity, N-hydroxyphthalimide (NHPI) esters have found many applications as radical precursors. Mechanistically, NHPI esters undergo a reductive decarboxylative fragmentation to provide a substrate radical capable of engaging in diverse transformations. Their reduction via single-electron transfer (SET) can occur under thermal, photochemical, or electrochemical conditions and can be influenced by a number of factors, including the nature of the electron donor, the use of Brønsted and Lewis acids, and the possibility of forming charge-transfer complexes. Such versatility creates many opportunities to influence the reaction conditions, providing a number of parameters with which to control reactivity. In this perspective, we provide an overview of the different mechanisms for radical reactions involving NHPI esters, with an emphasis on recent applications in radical additions, cyclizations and decarboxylative cross-coupling reactions. Within these reaction classes, we discuss the utility of the NHPI esters, with an eye towards their continued development in complexity-generating transformations.
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Affiliation(s)
| | - Jean-Philip Lumb
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
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16
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Laudadio G, Neigenfind P, Péter Á, Rubel CZ, Emmanuel MA, Oderinde MS, Ewing TEH, Palkowitz MD, Sloane JL, Gillman KW, Ridge D, Mandler MD, Bolduc PN, Nicastri MC, Zhang B, Clementson S, Petersen NN, Martín-Gago P, Mykhailiuk P, Engle KM, Baran PS. Nickel-Electrocatalytic Decarboxylative Arylation to Access Quaternary Centers. Angew Chem Int Ed Engl 2024; 63:e202314617. [PMID: 38181042 DOI: 10.1002/anie.202314617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 01/04/2024] [Accepted: 01/05/2024] [Indexed: 01/07/2024]
Abstract
There is a pressing need, particularly in the field of drug discovery, for general methods that will enable direct coupling of tertiary alkyl fragments to (hetero)aryl halides. Herein a uniquely powerful and simple set of conditions for achieving this transformation with unparalleled generality and chemoselectivity is disclosed. This new protocol is placed in context with other recently reported methods, applied to simplify the routes of known bioactive building blocks molecules, and scaled up in both batch and flow. The role of pyridine additive as well as the mechanism of this reaction are interrogated through Cyclic Voltammetry studies, titration experiments, control reactions with Ni(0) and Ni(II)-complexes, and ligand optimization data. Those studies indicate that the formation of a BINAPNi(0) is minimized and the formation of an active pyridine-stabilized Ni(I) species is sustained during the reaction. Our preliminary mechanistic studies ruled out the involvement of Ni(0) species in this electrochemical cross-coupling, which is mediated by Ni(I) species via a Ni(I)-Ni(II)-Ni(III)-Ni(I) catalytic cycle.
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Affiliation(s)
- Gabriele Laudadio
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Philipp Neigenfind
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Áron Péter
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Camille Z Rubel
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Megan A Emmanuel
- Chemical Process Development, Bristol Myers Squibb, 1 Squibb Drive, New Brunswick, NJ 08901, USA
| | - Martins S Oderinde
- Small Molecule Drug Discovery, Bristol Myers Squibb Research & Early Development, Route 206 & Province Line Road, Princeton, NJ 08543, USA
| | - Tamara El-Hayek Ewing
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Maximilian D Palkowitz
- Small Molecule Drug Discovery, Bristol Myers Squibb, Research & Early Development, 250 Water Street, Cambridge, MA 02141, USA
| | - Jack L Sloane
- Small Molecule Drug Discovery, Bristol Myers Squibb, Research & Early Development, 250 Water Street, Cambridge, MA 02141, USA
| | - Kevin W Gillman
- Small Molecule Drug Discovery, Bristol Myers Squibb, Research & Early Development, 250 Water Street, Cambridge, MA 02141, USA
| | - Daniel Ridge
- Small Molecule Drug Discovery, Bristol Myers Squibb, Research & Early Development, 250 Water Street, Cambridge, MA 02141, USA
| | - Michael D Mandler
- Small Molecule Drug Discovery, Bristol Myers Squibb Research & Early Development, Route 206 & Province Line Road, Princeton, NJ 08543, USA
| | | | | | - Benxiang Zhang
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | | | | | - Pablo Martín-Gago
- Research and Early Development, LEO Pharma A/S, 2750, Ballerup, Denmark
| | - Pavel Mykhailiuk
- Enamine Ltd., Winston Churchill Street 78, 02094, Kyiv, Ukraine
- Chemistry Department, Taras Shevchenko National University of Kyiv, Volodymyrska 64, 01601, Kyiv, Ukraine
| | - Keary M Engle
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Phil S Baran
- Department of Chemistry, Scripps Research, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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17
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Hooker LV, Bandar JS. Synthetic Advantages of Defluorinative C-F Bond Functionalization. Angew Chem Int Ed Engl 2023; 62:e202308880. [PMID: 37607025 PMCID: PMC10843719 DOI: 10.1002/anie.202308880] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 08/20/2023] [Accepted: 08/21/2023] [Indexed: 08/24/2023]
Abstract
Much progress has been made in the development of methods to both create compounds that contain C-F bonds and to functionalize C-F bonds. As such, C-F bonds are becoming common and versatile synthetic functional handles. This review summarizes the advantages of defluorinative functionalization reactions for small molecule synthesis. The coverage is organized by the type of carbon framework the fluorine is attached to for mono- and polyfluorinated motifs. The main challenges, opportunities and advances of defluorinative functionalization are discussed for each class of organofluorine. Most of the text focuses on case studies that illustrate how defluorofunctionalization can improve routes to synthetic targets or how the properties of C-F bonds enable unique mechanisms and reactions. The broader goal is to showcase the opportunities for incorporating and exploiting C-F bonds in the design of synthetic routes, improvement of specific reactions and advent of new methods.
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Affiliation(s)
- Leidy V Hooker
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
| | - Jeffrey S Bandar
- Department of Chemistry, Colorado State University, Fort Collins, CO, 80523, USA
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18
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Johnston B, Loh DM, Nocera DG. Substrate-Mediator Duality of 1,4-Dicyanobenzene in Electrochemical C(sp 2 )-C(sp 3 ) Bond Formation with Alkyl Bromides. Angew Chem Int Ed Engl 2023; 62:e202312128. [PMID: 37857567 DOI: 10.1002/anie.202312128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 10/11/2023] [Accepted: 10/17/2023] [Indexed: 10/21/2023]
Abstract
Electrochemical approaches to form C(sp2 )-C(sp3 ) bonds have focused on coupling C(sp3 ) electrophiles that form stabilized carbon-centered radicals upon reduction or oxidation. Whereas alkyl bromides are desirable C(sp3 ) coupling partners owing to their availability and cost-effectiveness, their tendency to undergo radical-radical homocoupling makes them challenging substrates for electroreductive cross-coupling. Herein, we disclose a metal-free regioselective cross-coupling of 1,4-dicyanobenzene, a useful precursor to aromatic nitriles, and alkyl bromides. Alkyl bromide reduction is mediated directly by 1,4-dicyanobenzene radical anions, leading to negligible homocoupling and high cross-selectivity to form 1,4-alkyl cyanobenzenes. The cross-coupling scheme is compatible with oxidatively sensitive and acidic functional groups such as amines and alcohols, which have proven difficult to incorporate in alternative electrochemical approaches using carboxylic acids as C(sp3 ) precursors.
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Affiliation(s)
- Brandon Johnston
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Daniel M Loh
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Daniel G Nocera
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
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19
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Tolchin ZA, Dukes DM, Gharbaoui LM, Smith JM. Dearomative Access to (-)-Thebaine and Derivatives. Org Lett 2023; 25:8424-8428. [PMID: 37976554 DOI: 10.1021/acs.orglett.3c03270] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
A synthesis of the natural product thebaine is reported in eight steps from commercially available starting materials, hinging on the dearomatization and coupling of simple aromatic starting materials. This provides divergent access to two unnatural opioid derivatives and is aimed at the long-term development of synthetic opioid analogs of the "wonderdrug" Naloxone. Additionally, a formal enantioselective synthesis of all reported targets is disclosed that leverages a catalytic asymmetric dearomatization via anion-pairing catalysis.
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Affiliation(s)
- Zachary A Tolchin
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Dallas M Dukes
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Leanna M Gharbaoui
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
| | - Joel M Smith
- Department of Chemistry and Biochemistry, Florida State University, 95 Chieftan Way, Tallahassee, Florida 32306, United States
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20
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Rein J, Zacate SB, Mao K, Lin S. A tutorial on asymmetric electrocatalysis. Chem Soc Rev 2023; 52:8106-8125. [PMID: 37910160 PMCID: PMC10842033 DOI: 10.1039/d3cs00511a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2023]
Abstract
Electrochemistry has emerged as a powerful means to enable redox transformations in modern chemical synthesis. This tutorial review delves into the unique advantages of electrochemistry in the context of asymmetric catalysis. While electrochemistry has historically been used as a green and mild alternative for established enantioselective transformations, in recent years asymmetric electrocatalysis has been increasingly employed in the discovery of novel asymmetric methodologies based on reaction mechanisms unique to electrochemistry. This tutorial review first provides a brief tutorial introduction to electrosynthesis, then explores case studies on homogenous small molecule asymmetric electrocatalysis. Each case study serves to highlight a key advance in the field, starting with the historic electrification of known asymmetric transformations and culminating with modern methods relying on unique electrochemical mechanistic sequences. Finally, we highlight case studies in the emerging reasearch areas at the interface of asymmetric electrocatalysis with biocatalysis and heterogeneous catalysis.
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Affiliation(s)
- Jonas Rein
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Samson B Zacate
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Kaining Mao
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA
| | - Song Lin
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
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21
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Palkowitz MD, Emmanuel MA, Oderinde MS. A Paradigm Shift in Catalysis: Electro- and Photomediated Nickel-Catalyzed Cross-Coupling Reactions. Acc Chem Res 2023; 56:2851-2865. [PMID: 37772915 DOI: 10.1021/acs.accounts.3c00479] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023]
Abstract
ConspectusTransition-metal catalyzed cross-coupling reactions are fundamental reactions in organic chemistry, facilitating strategic bond formations for accessing natural products, organic materials, agrochemicals, and pharmaceuticals. Redox chemistry enables access to elusive cross-coupling mechanisms through single-electron processes as an alternative to classical two-electron strategies predominated by palladium catalysis. The seminal reports of Baran, MacMillan, Doyle, Molander, Weix, Lin, Fu, Reisman, and others in merging redox perturbation (photochemical, electrochemical, and purely chemical) with catalysis are pivotal to the current resurgence and mechanistic understanding of first-row transition metal-based catalysis. The hallmark of this redox platform is the systematic modulation of transition-metal oxidation states by a photoredox catalyst or at a heterogeneous electrode surface. Electrocatalysis and photocatalysis enhance transition metal catalysis' capacity for bond formation through electron- or energy-transfer processes that promote otherwise challenging elementary steps or elusive mechanisms. Cross-coupling conditions promoted by electrocatalysis and photocatalysis are mild, and bond formation proceeds with exceptionally high chemoselectivity and wide functional group tolerance. The interfacing of abundant first-row transition-metal catalysis with electrocatalysis and photocatalysis has brought about a paradigm shift in cross-coupling technology as practitioners are quickly applying these tools in synthesizing fine chemicals and pharmaceutically relevant motifs. In particular, the merger of Ni catalysis with electro- and photochemistry ushered in a new era for carbon-carbon and carbon-heteroatom cross-couplings with expanded generality compared to their thermally driven counterparts. Over the past decade, we have developed enabling photo- and electrochemical methods throughout our combined research experience in industry (BMS, AstraZeneca) and academia (Professor Baran, Scripps Research) in cross-disciplinary collaborative environments. In this Account, we will outline recent progress from our past and present laboratories in photo- and electrochemically mediated Ni-catalyzed cross-couplings. By highlighting these cross-coupling methodologies, we will also compare mechanistic features of both electro- and photochemical strategies for forging C(sp2)-C(sp3), C(sp3)-C(sp3), C-O, C-N, and C-S bonds. Through these side-by-side comparisons, we hope to demystify the subtle differences between the two complementary tools to enact redox control over transition metal catalysis. Finally, building off the collective experience of ourselves and the rest of the community, we propose a tactical user guide to photo- and electrochemically driven cross-coupling reactions to aid the practitioner in rapidly applying such tools in their synthetic designs.
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Affiliation(s)
- Maximilian D Palkowitz
- Small Molecule Drug Discovery, Bristol Myers Squibb, 250 Water Street, Cambridge, Massachusetts 02141, United States
| | - Megan A Emmanuel
- Chemical Process Development, Bristol Myers Squibb, 1 Squibb Drive, New Brunswick, New Jersey 08901, United States
| | - Martins S Oderinde
- Small Molecule Discovery Chemistry, Bristol Myers Squibb Research & Early Development, Route 206 & Province Line Road, Princeton, New Jersey 08543, United States
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22
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Mikhael M, Alektiar SN, Yeung CS, Wickens ZK. Translating Planar Heterocycles into Three-Dimensional Analogs by Photoinduced Hydrocarboxylation. Angew Chem Int Ed Engl 2023; 62:e202303264. [PMID: 37199340 PMCID: PMC10524292 DOI: 10.1002/anie.202303264] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 05/12/2023] [Accepted: 05/15/2023] [Indexed: 05/19/2023]
Abstract
The rapid preparation of complex three-dimensional (3D) heterocyclic scaffolds is a key challenge in modern medicinal chemistry. Despite the increased probability of clinical success for small molecule therapeutic candidates with increased 3D complexity, new drug targets remain dominated by flat molecules due to the abundance of coupling reactions available for their construction. In principle, heteroarene hydrofunctionalization reactions offer an opportunity to transform readily accessible planar molecules into more three-dimensionally complex analogs through the introduction of a single molecular vector. Unfortunately, dearomative hydrofunctionalization reactions remain limited. Herein, we report a new strategy to enable the dearomative hydrocarboxylation of indoles and related heterocycles. This reaction represents a rare example of a heteroarene hydrofunctionalization that meets the numerous requirements for broad implementation in drug discovery. The transformation is highly chemoselective, broad in scope, operationally simple, and readily amenable to high-throughput experimentation (HTE). Accordingly, this process will allow existing libraries of heteroaromatic compounds to be translated into diverse 3D analogs and enable exploration of new classes of medicinally relevant molecules.
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Affiliation(s)
- Myriam Mikhael
- Discovery Chemistry, Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, MA 02115, United States
| | - Sara N. Alektiar
- Department of Chemistry, University of Wisconsin-Madison; Madison, Wisconsin, 53706, United States
| | - Charles S. Yeung
- Discovery Chemistry, Merck & Co., Inc., 33 Avenue Louis Pasteur, Boston, MA 02115, United States
| | - Zachary K. Wickens
- Department of Chemistry, University of Wisconsin-Madison; Madison, Wisconsin, 53706, United States
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23
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Lutovsky GA, Gockel SN, Bundesmann MW, Bagley SW, Yoon TP. Iron-mediated modular decarboxylative cross-nucleophile coupling. Chem 2023; 9:1610-1621. [PMID: 37637494 PMCID: PMC10449378 DOI: 10.1016/j.chempr.2023.04.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/29/2023]
Abstract
Carboxylic acids are valuable building blocks for pharmaceutical discovery because of their chemical stability, commercial availability, and structural diversity. Decarboxylative coupling reactions enable versatile functionalization of these feedstock chemicals, but many of the most general methods require prefunctionalization of carboxylic acids with redox-active moieties. These internal oxidants can be costly, their installation impedes rapid library synthesis, and their use results in environmentally problematic organic byproducts. We report herein a method for the direct decarboxylative cross-coupling of native carboxylic acids with nucleophilic coupling partners mediated by inexpensive, terrestrially abundant, and nontoxic Fe(III) salts. This method involves an initial photochemical decarboxylation followed by radical-polar crossover, which enables the construction of diverse carbon-carbon, carbon-oxygen, and carbon-nitrogen bonds with remarkable generality.
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Affiliation(s)
- Grace A. Lutovsky
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, WI 53706, USA
- These authors contributed equally
| | - Samuel N. Gockel
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, WI 53706, USA
- Department of Chemistry, Colorado State University Pueblo, 2200 Bonforte Boulevard, Pueblo, CO 81001, USA
| | | | - Scott W. Bagley
- Medicine Design, Pfizer Inc., Eastern Point Road, Groton, CT 06340, USA
| | - Tehshik P. Yoon
- Department of Chemistry, University of Wisconsin–Madison, 1101 University Avenue, Madison, WI 53706, USA
- Lead contact
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24
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Alektiar SN, Han J, Dang Y, Rubel CZ, Wickens ZK. Radical Hydrocarboxylation of Unactivated Alkenes via Photocatalytic Formate Activation. J Am Chem Soc 2023; 145:10991-10997. [PMID: 37186951 PMCID: PMC10636750 DOI: 10.1021/jacs.3c03671] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Herein we disclose a strategy to promote the hydrocarboxylation of unactivated alkenes using photochemical activation of formate salts. We illustrate that an alternative initiation mechanism circumvents the limitations of prior approaches and enables hydrocarboxylation of this challenging substrate class. Specifically, we found that accessing the requisite thiyl radical initiator without an exogenous chromophore eliminates major byproducts that have plagued attempts to exploit similar reactivity for unactivated alkene substrates. This redox-neutral method is technically simple to execute and effective across a broad range of alkene substrates. Feedstock alkenes, such as ethylene, are hydrocarboxylated at ambient temperature and pressure. A series of radical cyclization experiments indicate how the reactivity described in this report can be diverted by more complex radical processes.
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Affiliation(s)
- Sara N. Alektiar
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Jimin Han
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Y Dang
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Camille Z. Rubel
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Zachary K. Wickens
- Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
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25
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Bakanas I, Tang JC, Sarpong R. Skeletal diversification by C-C cleavage to access bicyclic frameworks from a common tricyclooctane intermediate. Chem Commun (Camb) 2023; 59:3858-3861. [PMID: 36916206 PMCID: PMC10518267 DOI: 10.1039/d3cc00945a] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Herein, the diversification of tricyclo[3.2.1.03,6]octane scaffolds to afford diverse bicyclic scaffolds is described. The strained tricyclooctanes are prepared in two steps featuring a blue light-mediated [2+2] cycloaddition. Strategies for the cleavage of this scaffold were then explored resulting in the selective syntheses of the bicyclo[3.1.1]heptane, bicyclo[3.2.1]octane, and bicyclo[3.2.0]heptane cores. These findings may guide future studies of C-C cleavage reactions in strained carbon frameworks and their application in complex molecule synthesis.
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Affiliation(s)
- Ian Bakanas
- Department of Chemistry, University of California-Berkeley, Berkeley, California, USA.
| | - Jess C Tang
- Department of Chemistry, University of California-Berkeley, Berkeley, California, USA.
| | - Richmond Sarpong
- Department of Chemistry, University of California-Berkeley, Berkeley, California, USA.
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26
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Wang Y, Xu J, Pan Y, Wang Y. Recent advances in electrochemical deoxygenation reactions of organic compounds. Org Biomol Chem 2023; 21:1121-1133. [PMID: 36655598 DOI: 10.1039/d2ob01817a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
As naturally abundant and recyclable industrial feedstock, alcohols and carboxylic acids have drawn tremendous attention in medicinal chemistry and polymer chemistry. The selective C-O cleavage of the hydroxyl group represents an appealing strategy to deliver alkyl and carbonyl moieties into organic molecules. Classical examples of hydroxyl activation include the Appel reaction, Mitsunobu reaction, and Barton-McCombie deoxygenation. However, these early approaches still require large amounts of oxidants or reductants, and suffer from harsh conditions and low atom economy. Electrosynthesis has proven to be an effective and mild way of the modern chemical industry, avoiding the use of chemical oxidants/reductants through the action of an electric current. In this review, we have summarized the recent advances in electrochemical deoxygenation reactions and categorized the deoxygenation methods by different functionalities.
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Affiliation(s)
- Yang Wang
- School of Chemistry and Life Sciences, Suzhou University of Science and Technology, Suzhou 215009, China
| | - Jia Xu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Yi Pan
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
| | - Yi Wang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China.
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