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Alekseychuk M, Heretsch P. Biogenetic space-guided synthesis of rearranged terpenoids. Chem Commun (Camb) 2023. [PMID: 37162324 DOI: 10.1039/d3cc01009k] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Natural product chemistry is constantly challenged by newly discovered, complex molecules. Elements of complexity arise from unprecedented frameworks, with a large amount of densely packed stereogenic centres and different functional groups along with a generally high oxidation state. As a prime example, rearranged triterpenoids possess all these elements. For their total synthesis, a limit of what is considered sensible in terms of steps and yield is frequently reached. As an alternative, semisynthetic approaches have gained a great amount of attention in recent years. In this featured article, we present our and others' contributions towards the development of efficient and economic syntheses of complex terpenoid natural products and elaborate on the underlying rationale of biogenetic space-guided synthetic analysis.
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Affiliation(s)
- Mykhaylo Alekseychuk
- Institute of Organic Chemistry, Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany.
| | - Philipp Heretsch
- Institute of Organic Chemistry, Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany.
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2
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Cheng J, Liu WQ, Zhu X, Zhang Q. Functional Diversity of HemN-like Proteins. ACS BIO & MED CHEM AU 2022; 2:109-119. [PMID: 37101745 PMCID: PMC10114718 DOI: 10.1021/acsbiomedchemau.1c00058] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
HemN is a radical S-adenosylmethionine (SAM) enzyme that catalyzes the anaerobic oxidative decarboxylation of coproporphyrinogen III to produce protoporphyrinogen IX, a key intermediate in heme biosynthesis. Proteins homologous to HemN (HemN-like proteins) are widespread in both prokaryotes and eukaryotes. Although these proteins are in most cases annotated as anaerobic coproporphyrinogen III oxidases (CPOs) in the public database, many of them are actually not CPOs but have diverse functions such as methyltransferases, cyclopropanases, heme chaperones, to name a few. This Perspective discusses the recent advances in the understanding of HemN-like proteins, and particular focus is placed on the diverse chemistries and functions of this growing protein family.
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Affiliation(s)
- Jinduo Cheng
- Department of Chemistry, Fudan University, Shanghai, 200433, China
| | - Wan-Qiu Liu
- Department of Chemistry, Fudan University, Shanghai, 200433, China
| | - Xiaoyu Zhu
- Department of Chemistry, Fudan University, Shanghai, 200433, China
| | - Qi Zhang
- Department of Chemistry, Fudan University, Shanghai, 200433, China
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3
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Li X, Zhang Z, Fan H, Miao Y, Tian H, Gu Y, Gui J. Concise Synthesis of 9,11-Secosteroids Pinnigorgiols B and E. J Am Chem Soc 2021; 143:4886-4890. [PMID: 33761241 DOI: 10.1021/jacs.0c13426] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Pinnigorgiols B and E are 9,11-secosteroids with a unique tricyclic γ-diketone framework. Herein, we report the first synthesis of these natural products from inexpensive, commercially available ergosterol. This synthesis features a semipinacol rearrangement and an acyl radical cyclization/hemiketalization cascade; the latter efficiently assembled the tricyclic γ-diketone skeleton, with two rings and three contiguous stereogenic centers being formed in a single step.
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Affiliation(s)
- Xinghui Li
- CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Zeliang Zhang
- CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Huafang Fan
- Shaanxi Key Laboratory of Natural Products & Chemical Biology, College of Chemistry & Pharmacy, Northwest A&F University, 22 Xinong Road, Yangling 712100, Shaanxi, China
| | - Yinlong Miao
- Shaanxi Key Laboratory of Natural Products & Chemical Biology, College of Chemistry & Pharmacy, Northwest A&F University, 22 Xinong Road, Yangling 712100, Shaanxi, China
| | - Hailong Tian
- CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Yucheng Gu
- Syngenta, Jealott's Hill International Research Centre, Bracknell, Berkshire RG42 6EY, United Kingdom
| | - Jinghan Gui
- CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
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4
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Shrestha M, Wu X, Huang W, Qu J, Chen Y. Recent advances in transition metal-catalyzed reactions of carbamoyl chlorides. Org Chem Front 2021. [DOI: 10.1039/d0qo01648a] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
This review highlights the recent advancements of carbamoyl chlorides in transition metal-catalyzed reactions to access various amide-containing molecules and heterocycles.
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Affiliation(s)
- Mohini Shrestha
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering
- Feringa Nobel Prize Scientist Joint Research Center
- Frontiers Science Center for Materiobiology and Dynamic Chemistry
- School of Chemistry and Molecular Engineering
- East China University of Science & Technology
| | - Xianqing Wu
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering
- Feringa Nobel Prize Scientist Joint Research Center
- Frontiers Science Center for Materiobiology and Dynamic Chemistry
- School of Chemistry and Molecular Engineering
- East China University of Science & Technology
| | - Wenyi Huang
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering
- Feringa Nobel Prize Scientist Joint Research Center
- Frontiers Science Center for Materiobiology and Dynamic Chemistry
- School of Chemistry and Molecular Engineering
- East China University of Science & Technology
| | - Jingping Qu
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering
- Feringa Nobel Prize Scientist Joint Research Center
- Frontiers Science Center for Materiobiology and Dynamic Chemistry
- School of Chemistry and Molecular Engineering
- East China University of Science & Technology
| | - Yifeng Chen
- Key Laboratory for Advanced Materials and Joint International Research Laboratory of Precision Chemistry and Molecular Engineering
- Feringa Nobel Prize Scientist Joint Research Center
- Frontiers Science Center for Materiobiology and Dynamic Chemistry
- School of Chemistry and Molecular Engineering
- East China University of Science & Technology
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5
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6
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Wang Y, Deng L, Zhang X, Mou Z, Niu D. A Radical Approach to Making Unnatural Amino Acids: Conversion of C−S Bonds in Cysteine Derivatives into C−C Bonds. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202012503] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Yingwei Wang
- Department of Emergency State Key Laboratory of Biotherapy West China Hospital, and School of Chemical Engineering Sichuan University No. 17 Renmin Nan Road Chengdu 610041 China
| | - Li‐Fan Deng
- Department of Emergency State Key Laboratory of Biotherapy West China Hospital, and School of Chemical Engineering Sichuan University No. 17 Renmin Nan Road Chengdu 610041 China
| | - Xia Zhang
- Department of Emergency State Key Laboratory of Biotherapy West China Hospital, and School of Chemical Engineering Sichuan University No. 17 Renmin Nan Road Chengdu 610041 China
| | - Ze‐Dong Mou
- Department of Emergency State Key Laboratory of Biotherapy West China Hospital, and School of Chemical Engineering Sichuan University No. 17 Renmin Nan Road Chengdu 610041 China
| | - Dawen Niu
- Department of Emergency State Key Laboratory of Biotherapy West China Hospital, and School of Chemical Engineering Sichuan University No. 17 Renmin Nan Road Chengdu 610041 China
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7
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Wang Y, Deng LF, Zhang X, Mou ZD, Niu D. A Radical Approach to Making Unnatural Amino Acids: Conversion of C−S Bonds in Cysteine Derivatives into C−C Bonds. Angew Chem Int Ed Engl 2020; 60:2155-2159. [PMID: 33022829 DOI: 10.1002/anie.202012503] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/02/2020] [Indexed: 02/05/2023]
Affiliation(s)
- Yingwei Wang
- Department of Emergency, State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering, Sichuan University, No. 17 Renmin Nan Road, Chengdu, 610041, China
| | - Li-Fan Deng
- Department of Emergency, State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering, Sichuan University, No. 17 Renmin Nan Road, Chengdu, 610041, China
| | - Xia Zhang
- Department of Emergency, State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering, Sichuan University, No. 17 Renmin Nan Road, Chengdu, 610041, China
| | - Ze-Dong Mou
- Department of Emergency, State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering, Sichuan University, No. 17 Renmin Nan Road, Chengdu, 610041, China
| | - Dawen Niu
- Department of Emergency, State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering, Sichuan University, No. 17 Renmin Nan Road, Chengdu, 610041, China
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8
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Shang W, Su SN, Shi R, Mou ZD, Yu GQ, Zhang X, Niu D. Generation of Glycosyl Radicals from Glycosyl Sulfoxides and Its Use in the Synthesis of C-linked Glycoconjugates. Angew Chem Int Ed Engl 2020; 60:385-390. [PMID: 32935426 DOI: 10.1002/anie.202009828] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 09/08/2020] [Indexed: 02/05/2023]
Abstract
We here report glycosyl sulfoxides appended with an aryl iodide moiety as readily available, air and moisture stable precursors to glycosyl radicals. These glycosyl sulfoxides could be converted to glycosyl radicals by way of a rapid and efficient intramolecular radical substitution event. The use of this type of precursors enabled the synthesis of various complex C-linked glycoconjugates under mild conditions. This reaction could be performed in aqueous media and is amenable to the synthesis of glycopeptidomimetics and carbohydrate-DNA conjugates.
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Affiliation(s)
- Weidong Shang
- Department of Emergency, State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering, Sichuan University, No. 17 Renmin Nan Road, Chengdu, 610041, China
| | - Sheng-Nan Su
- Department of Emergency, State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering, Sichuan University, No. 17 Renmin Nan Road, Chengdu, 610041, China
| | - Rong Shi
- Department of Emergency, State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering, Sichuan University, No. 17 Renmin Nan Road, Chengdu, 610041, China
| | - Ze-Dong Mou
- Department of Emergency, State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering, Sichuan University, No. 17 Renmin Nan Road, Chengdu, 610041, China
| | - Guo-Qiang Yu
- Discovery Chemistry Unit, HitGen Inc., Building 6, No. Huigu 1st East Road, Tianfu International Bio-Town, Shuangliu District, Chengdu, 610200, China
| | - Xia Zhang
- Department of Emergency, State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering, Sichuan University, No. 17 Renmin Nan Road, Chengdu, 610041, China
| | - Dawen Niu
- Department of Emergency, State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering, Sichuan University, No. 17 Renmin Nan Road, Chengdu, 610041, China
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9
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Shang W, Su S, Shi R, Mou Z, Yu G, Zhang X, Niu D. Generation of Glycosyl Radicals from Glycosyl Sulfoxides and Its Use in the Synthesis of
C
‐linked Glycoconjugates. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009828] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Weidong Shang
- Department of Emergency State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering Sichuan University No. 17 Renmin Nan Road Chengdu 610041 China
| | - Sheng‐Nan Su
- Department of Emergency State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering Sichuan University No. 17 Renmin Nan Road Chengdu 610041 China
| | - Rong Shi
- Department of Emergency State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering Sichuan University No. 17 Renmin Nan Road Chengdu 610041 China
| | - Ze‐Dong Mou
- Department of Emergency State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering Sichuan University No. 17 Renmin Nan Road Chengdu 610041 China
| | - Guo‐Qiang Yu
- Discovery Chemistry Unit HitGen Inc. Building 6, No. Huigu 1st East Road, Tianfu International Bio-Town, Shuangliu District Chengdu 610200 China
| | - Xia Zhang
- Department of Emergency State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering Sichuan University No. 17 Renmin Nan Road Chengdu 610041 China
| | - Dawen Niu
- Department of Emergency State Key Laboratory of Biotherapy, West China Hospital, and School of Chemical Engineering Sichuan University No. 17 Renmin Nan Road Chengdu 610041 China
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10
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Ji W, Ji X, Zhang Q, Mandalapu D, Deng Z, Ding W, Sun P, Zhang Q. Sulfonium‐Based Homolytic Substitution Observed for the Radical SAM Enzyme HemN. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202000812] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Wenjuan Ji
- Department of Chemistry Fudan University Shanghai 200433 China
| | - Xinjian Ji
- Department of Chemistry Fudan University Shanghai 200433 China
| | - Qi Zhang
- Department of Chemistry Fudan University Shanghai 200433 China
| | | | - Zixin Deng
- State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University Shanghai 200240 China
| | - Wei Ding
- State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University Shanghai 200240 China
| | - Peng Sun
- School of Pharmacy Second Military Medical University Shanghai 200433 China
| | - Qi Zhang
- Department of Chemistry Fudan University Shanghai 200433 China
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11
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Ji W, Ji X, Zhang Q, Mandalapu D, Deng Z, Ding W, Sun P, Zhang Q. Sulfonium‐Based Homolytic Substitution Observed for the Radical SAM Enzyme HemN. Angew Chem Int Ed Engl 2020; 59:8880-8884. [DOI: 10.1002/anie.202000812] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Indexed: 11/09/2022]
Affiliation(s)
- Wenjuan Ji
- Department of Chemistry Fudan University Shanghai 200433 China
| | - Xinjian Ji
- Department of Chemistry Fudan University Shanghai 200433 China
| | - Qi Zhang
- Department of Chemistry Fudan University Shanghai 200433 China
| | | | - Zixin Deng
- State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University Shanghai 200240 China
| | - Wei Ding
- State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University Shanghai 200240 China
| | - Peng Sun
- School of Pharmacy Second Military Medical University Shanghai 200433 China
| | - Qi Zhang
- Department of Chemistry Fudan University Shanghai 200433 China
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12
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Agrawal AR, Kumar NR, Debnath S, Das S, Kumar C, Zade SS. Radical-Cascade Avenue for 3,4-Fused-Ring-Substituted Thiophenes. Org Lett 2018; 20:4728-4731. [PMID: 30062891 DOI: 10.1021/acs.orglett.8b01577] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Abhijeet R. Agrawal
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, Nadia, West Bengal, India
| | - Neha Rani Kumar
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, Nadia, West Bengal, India
| | - Sashi Debnath
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, Nadia, West Bengal, India
| | - Sarasija Das
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, Nadia, West Bengal, India
| | - Chandan Kumar
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, Nadia, West Bengal, India
| | - Sanjio S. Zade
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, Nadia, West Bengal, India
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13
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Norman AR, Yousif MN, McErlean CSP. Photoredox-catalyzed indirect acyl radical generation from thioesters. Org Chem Front 2018. [DOI: 10.1039/c8qo00867a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A photoredox-catalyzed method for the indirect generation of acyl radicals from stable thioesters is described.
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14
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Vu MD, Das M, Liu XW. Direct Aldehyde Csp 2 -H Functionalization through Visible-Light-Mediated Photoredox Catalysis. Chemistry 2017; 23:15899-15902. [PMID: 29057525 DOI: 10.1002/chem.201704224] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Indexed: 12/22/2022]
Abstract
The development of methods for carbon-carbon bond formation under benign conditions is an ongoing challenge for synthetic chemists. In recent years there has been considerable interest in using selective C-H activation as a direct route for generating reactive intermediates. Herein, the use of visible-light-mediated dual photoredox organocatalysis as a mild and effective method for Csp2 -H activation of aldehydes is reported, resulting in the generation of acyl radicals. These nucleophilic acyl radical species can undergo either addition to electrophilic alkenes or nickel-catalyzed cross-coupling reactions to provide a quick access to broad range of unsymmetrical ketones, which are abundantly found in many organic building blocks.
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Affiliation(s)
- Minh Duy Vu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Mrinmoy Das
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
| | - Xue-Wei Liu
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore, 637371, Singapore
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15
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Fard MA, Khalili Najafabadi B, Hesari M, Workentin MS, Corrigan JF. New polydentate trimethylsilyl chalcogenide reagents for the assembly of polyferrocenyl architectures. Chemistry 2014; 20:7037-47. [PMID: 24806828 DOI: 10.1002/chem.201400185] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Indexed: 01/18/2023]
Abstract
A series of polychalcogenotrimethylsilane complexes Ar(CH2ESiMe3)n, (Ar = aryl; E = S, Se; n = 2, 3, and 4) can be prepared from the corresponding polyorganobromide and M[ESiMe3] (M = Na, Li). These represent the first examples of the incorporation of such a large number of reactive -ESiMe3 moieties onto an organic molecular framework. They are shown to be convenient reagents for the preparation of the polyferrocenylseleno- and thioesters from ferrocenoyl chloride. The synthesis, structures, and spectroscopic properties of the new silyl chalcogen complexes 1,4-(Me3SiECH2)2(C6Me4) (E = S, 1; E = Se, 2), 1,3,5-(Me3SiECH2)3(C6Me3) (E = S, 3; E = Se, 4) and 1,2,4,5-(Me3SiECH2)4(C6H2) (E = S, 5; E = Se, 6) and the polyferrocenyl chalcogenoesters [1,4-{FcC(O)ECH2}2(C6Me4)] (E = S, 7; E = Se, 8), [1,3,5-{FcC(O)ECH2}3(C6Me3)] (E = S, 9; E = Se, 10) and [1,2,4,5-{FcC(O)ECH2}4(C6H2)] (E = S, 11 illustrated; E = Se, 12) are reported. The new polysilylated reagents and polyferrocenyl chalcogenoesters have been characterized by multinuclear NMR spectroscopy ((1)H, (13)C, (77)Se), electrospray ionization mass spectrometry and, for complexes 1, 2, 3, 4, 7, 8, and 11, single-crystal X-ray diffraction. The cyclic voltammograms of complexes 7-11 are presented.
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Affiliation(s)
- Mahmood Azizpoor Fard
- Department of Chemistry, The University of Western Ontario, London, ON, N6A 5B7 (Canada), Fax: (+1)519-661-3022
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Affiliation(s)
- Fabrice Dénès
- Laboratoire CEISAM UMR CNRS 6230 - UFR des Sciences et Techniques, Université de Nantes , 2 rue de la Houssinière, BP 92208 - 44322 Nantes Cedex 3, France
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17
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18
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Dénès F, Schiesser CH, Renaud P. Thiols, thioethers, and related compounds as sources of C-centred radicals. Chem Soc Rev 2013; 42:7900-42. [DOI: 10.1039/c3cs60143a] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Noel A, Delpech B, Crich D. Comparison of the reactivity of β-thiolactones and β-lactones toward ring-opening by thiols and amines. Org Biomol Chem 2012; 10:6480-3. [PMID: 22751994 DOI: 10.1039/c2ob25640a] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
An investigation into the comparative reactivity of simple β-lactones and β-thiolactones toward a thiol and a primary amine is reported. A simple 3-mercaptomethyl-2-oxetanone is found to undergo rearrangement in the presence of aqueous base to give the corresponding thietane-3-carboxylic acid rather than the 3-hydroxymethyl-2-thietanone. Implications for the use of β-thiolactones in bioorganic and medicinal chemistry are discussed.
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Affiliation(s)
- Amandine Noel
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles, CNRS, 1 Avenue de la Terrasse, 91190 Gif-sur-Yvette, France
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20
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Crich D. Methodology development and physical organic chemistry: a powerful combination for the advancement of glycochemistry. J Org Chem 2011; 76:9193-209. [PMID: 21919522 PMCID: PMC3215858 DOI: 10.1021/jo2017026] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
This Perspective outlines work in the Crich group on the diastereoselective synthesis of the so-called difficult classes of glycosidic bond: the 2-deoxy-β-glycopyranosides, the β-mannopyranosides, the α-sialosides, the α-glucopyranosides, and the β-arabinofuranosides with an emphasis on the critical interplay between mechanism and methodology development.
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Affiliation(s)
- David Crich
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
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21
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Kyne SH, Aitken HM, Schiesser CH, Lacôte E, Malacria M, Ollivier C, Fensterbank L. Intramolecular homolytic substitution of sulfinates and sulfinamides – a computational study. Org Biomol Chem 2011; 9:3331-7. [DOI: 10.1039/c1ob05043e] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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23
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Coulomb J, Certal V, Larraufie MH, Ollivier C, Corbet JP, Mignani G, Fensterbank L, Lacôte E, Malacria M. Intramolecular Homolytic Substitution of Sulfinates and Sulfinamides. Chemistry 2009; 15:10225-32. [DOI: 10.1002/chem.200900942] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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24
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Chernega AN, Davies SG, Goodwin CJ, Hepworth D, Kurosawa W, Roberts PM, Thomson JE. The Chiral Auxiliary N-1-(1′-Naphthyl)ethyl-O-tert-butylhydroxylamine: A Chiral Weinreb Amide Equivalent. Org Lett 2009; 11:3254-7. [DOI: 10.1021/ol901174t] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alexander N. Chernega
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K., and AstraZeneca R&D Charnwood, Process R&D, Bakewell Road, Loughborough, Leicestershire LE11 5RH, U.K
| | - Stephen G. Davies
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K., and AstraZeneca R&D Charnwood, Process R&D, Bakewell Road, Loughborough, Leicestershire LE11 5RH, U.K
| | - Christopher J. Goodwin
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K., and AstraZeneca R&D Charnwood, Process R&D, Bakewell Road, Loughborough, Leicestershire LE11 5RH, U.K
| | - David Hepworth
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K., and AstraZeneca R&D Charnwood, Process R&D, Bakewell Road, Loughborough, Leicestershire LE11 5RH, U.K
| | - Wataru Kurosawa
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K., and AstraZeneca R&D Charnwood, Process R&D, Bakewell Road, Loughborough, Leicestershire LE11 5RH, U.K
| | - Paul M. Roberts
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K., and AstraZeneca R&D Charnwood, Process R&D, Bakewell Road, Loughborough, Leicestershire LE11 5RH, U.K
| | - James E. Thomson
- Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K., and AstraZeneca R&D Charnwood, Process R&D, Bakewell Road, Loughborough, Leicestershire LE11 5RH, U.K
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25
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Womack GB, Angeles JG, Fanelli VE, Indradas B, Snowden RL, Sonnay P. Indanones and Indenols from 2-Alkylcinnamaldehydes via the Intramolecular Friedel−Crafts Reaction of Geminal Diacetates. J Org Chem 2009; 74:5738-41. [DOI: 10.1021/jo900910b] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Gary B. Womack
- Corporate R&D Division, Firmenich, Inc., P.O. Box 5880, Princeton, New Jersey 08543
| | - John G. Angeles
- Corporate R&D Division, Firmenich, Inc., P.O. Box 5880, Princeton, New Jersey 08543
| | - Vincent E. Fanelli
- Corporate R&D Division, Firmenich, Inc., P.O. Box 5880, Princeton, New Jersey 08543
| | - Brinda Indradas
- Corporate R&D Division, Firmenich, Inc., P.O. Box 5880, Princeton, New Jersey 08543
| | - Roger L. Snowden
- Corporate R&D Division, Firmenich, Inc., P.O. Box 5880, Princeton, New Jersey 08543
| | - Philippe Sonnay
- Corporate R&D Division, Firmenich, Inc., P.O. Box 5880, Princeton, New Jersey 08543
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26
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Singh PP, Yadav AK, Ila H, Junjappa H. Novel Route to 2,3-Substituted Benzo[b]thiophenes via Intramolecular Radical Cyclization. J Org Chem 2009; 74:5496-501. [DOI: 10.1021/jo900615p] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Prabal P. Singh
- Department of Chemistry, Indian Institute of Technology, Kanpur-208016, India
| | - A. K. Yadav
- Department of Chemistry, Indian Institute of Technology, Kanpur-208016, India
| | - H. Ila
- Department of Chemistry, Indian Institute of Technology, Kanpur-208016, India
| | - H. Junjappa
- Department of Chemistry, Indian Institute of Technology, Kanpur-208016, India
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27
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Carta P, Puljic N, Robert C, Dhimane AL, Ollivier C, Fensterbank L, Lacôte E, Malacria M. Intramolecular homolytic substitution at the sulfur atom: an alternative way to generate phosphorus- and sulfur-centered radicals. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.08.108] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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28
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Taaning RH, Thim L, Karaffa J, Campaña AG, Hansen AM, Skrydstrup T. SmI2-promoted intra- and intermolecular C–C bond formation with chiral N-acyl oxazolidinones. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.09.044] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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29
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30
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Lobachevsky S, Schiesser CH, Gupta V. Tandem homolytic addition/substitution sequences and their application to tin-free radical chemistry. Tetrahedron Lett 2007. [DOI: 10.1016/j.tetlet.2007.10.139] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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31
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32
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Yamashita A, Norton EB, Hanna C, Shim J, Salaski EJ, Zhou D, Mansour TS. Synthesis of 3,3‐Dimethyl‐4‐chromanones: Improved Procedures Without Ring Opening. SYNTHETIC COMMUN 2006. [DOI: 10.1080/00397910500383543] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Ayako Yamashita
- a Chemical and Screening Sciences, Wyeth Research, Pearl River , New York, USA
| | - Emily B. Norton
- a Chemical and Screening Sciences, Wyeth Research, Pearl River , New York, USA
| | - Cilien Hanna
- a Chemical and Screening Sciences, Wyeth Research, Pearl River , New York, USA
| | - Jaechul Shim
- a Chemical and Screening Sciences, Wyeth Research, Pearl River , New York, USA
| | - Edward J. Salaski
- a Chemical and Screening Sciences, Wyeth Research, Pearl River , New York, USA
| | - Dahui Zhou
- a Chemical and Screening Sciences, Wyeth Research, Pearl River , New York, USA
| | - Tarek S. Mansour
- a Chemical and Screening Sciences, Wyeth Research, Pearl River , New York, USA
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33
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Benati L, Bencivenni G, Leardini R, Minozzi M, Nanni D, Scialpi R, Spagnolo P, Zanardi G. Generation and Cyclization of Unsaturated Carbamoyl Radicals Derived from S-4-Pentynyl Carbamothioates under Tin-Free Conditions. J Org Chem 2006; 71:3192-7. [PMID: 16599618 DOI: 10.1021/jo0602064] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The radical reaction of benzenethiol with S-4-pentynyl carbamothioates provides a valuable protocol for the tin-free generation of carbamoyl radicals, which arise from intramolecular substitution at sulfur by the initial sulfanylvinyl radicals. This procedure can be usefully employed to achieve N-benzylcarbamoyl radical 5-exo and 4-exo cyclizations leading, respectively, to pyrrolidinones and azetidinones, although, for the latter, it seems of lesser utility. Novel evidence is presented that N-tosyl-substituted carbamoyl radicals display a peculiar tendency to yield the corresponding isocyanate by beta-elimination of the tosyl radical.
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Affiliation(s)
- Luisa Benati
- Dipartimento di Chimica Organica A. Mangini, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
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34
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Chatgilialoglu C, Ferreri C, Lucarini M, Venturini A, Zavitsas AA. 5-exo-trig Versus 6-endo-trig Cyclization of Alk-5-enoyl Radicals: The Role of One-Carbon Ring Expansion. Chemistry 2006. [DOI: 10.1002/chem.19970030309] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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35
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Formation of Cyclic Sulfinates and Sulfinamides through Homolytic Substitution at the Sulfur Atom. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200503369] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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36
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Coulomb J, Certal V, Fensterbank L, Lacôte E, Malacria M. Formation of Cyclic Sulfinates and Sulfinamides through Homolytic Substitution at the Sulfur Atom. Angew Chem Int Ed Engl 2006; 45:633-7. [PMID: 16365844 DOI: 10.1002/anie.200503369] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Julien Coulomb
- Laboratoire de Chimie Organique, Institut de Chimie Moléculaire, Université Pierre et Marie Curie, Case 229, 4 place Jussieu, 75252 Paris cedex 05, France
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37
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Schiesser CH. Taming the free radical shrew ? learning to control homolytic reactions at higher heteroatoms. Chem Commun (Camb) 2006:4055-65. [PMID: 17024249 DOI: 10.1039/b608150a] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Free radical chemistry has come a long way in a relatively short period of time. Armed with mechanistic and rate constant data, the synthetic practitioner can now apply free radical chemistry to the synthesis of many different classes of target molecule with confidence. This Feature Article highlights progress made in the understanding and application of free radical reactions at main group higher heteroatoms and demonstrates how this knowledge can be used to construct interesting higher heterocycles, many of which exhibit biological activity, through the use of intramolecular homolytic substitution chemistry.
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Affiliation(s)
- Carl H Schiesser
- Australian Research Council Centre for Free Radical Chemistry and Biotechnology, School of Chemistry, The University of Melbourne, Victoria, Australia.
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38
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Majumdar KC, Basu PK, Mukhopadhyay PP. Formation of five- and six-membered heterocyclic rings under radical cyclisation conditions. Tetrahedron 2005. [DOI: 10.1016/j.tet.2005.07.079] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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39
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Cho CH, Kim S, Yamane M, Miyauchi H, Narasaka K. Radical Cyclizations of Alkenyl Acylphosphonate Derivatives under Thermal and Photochemical Conditions. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2005. [DOI: 10.1246/bcsj.78.1665] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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40
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Crich D, Hutton TK, Ranganathan K. Is There a Homolytic Substitution Chemistry (SH2) of Sulfones? J Org Chem 2005; 70:7672-8. [PMID: 16149798 DOI: 10.1021/jo050990c] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] A series of 2-alkylsulfonyl-2'-biphenyl radicals, in which the alkyl group is primary, secondary, or tertiary, were generated and the products of their reactions investigated. Dibenzothiophene S,S-dioxide was not identified among the products, which arose mainly from intramolecular hydrogen abstraction from the alkyl group or addition to the solvent, benzene. On this basis, it is concluded that homolytic substitution at sulfonyl sulfur, if possible at all, is too slow to take precedence over a number of competing decomposition pathways. Previous literature results suggesting the possibility of intramolecular homolytic substitution at sulfonyl sulfur may be explained by alternative processes.
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Affiliation(s)
- David Crich
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA.
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41
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Geney R, Sun L, Pera P, Bernacki RJ, Xia S, Horwitz SB, Simmerling CL, Ojima I. Use of the tubulin bound paclitaxel conformation for structure-based rational drug design. ACTA ACUST UNITED AC 2005; 12:339-48. [PMID: 15797218 DOI: 10.1016/j.chembiol.2005.01.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Revised: 12/25/2004] [Accepted: 01/04/2005] [Indexed: 11/19/2022]
Abstract
A new computational docking protocol has been developed and used in combination with conformational information inferred from REDOR-NMR experiments on microtubule bound 2-(p-fluorobenzoyl)paclitaxel to delineate a unique tubulin binding structure of paclitaxel. A conformationally constrained macrocyclic taxoid bearing a linker between the C-14 and C-3'N positions has been designed and synthesized to enforce this "REDOR-taxol" conformation. The novel taxoid SB-T-2053 inhibits the growth of MCF-7 and LCC-6 human breast cancer cells (wild-type and drug resistant) on the same order of magnitude as paclitaxel. Moreover, SB-T-2053 induces in vitro tubulin polymerization at least as well as paclitaxel, which directly validates our drug design process. These results open a new avenue for drug design of next generation taxoids and other microtubule-stabilizing agents based on the refined structural information of drug-tubulin complexes, in accordance with typical enzyme-inhibitor medicinal chemistry precepts.
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Affiliation(s)
- Raphaël Geney
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, New York, 11794, USA
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42
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Hayes CJ, Herbert NMA, Harrington-Frost NM, Pattenden G. α,β-Unsaturated and cyclopropyl acyl radicals, and their ketene alkyl radical equivalents. Ring synthesis and tandem cyclisation reactions. Org Biomol Chem 2005; 3:316-27. [PMID: 15632975 DOI: 10.1039/b413815p] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Treatment of the alpha,beta-unsaturated selenyl esters 12 and 14 with Bu(3)SnH-AIBN produces the corresponding 2-cyclohexenones 13 and 15 respectively via presumed alpha-ketene alkyl radical intermediates, viz. 10. By contrast, the 2,7-diene esters 34 and 39 undergo tandem radical cyclisations producing diquinanes, e.g.(76%), and the corresponding allene-substituted alpha,beta-unsaturated selenyl ester 48 gives the cyclooctadienone 56 on treatment with Bu(3)SnH-AIBN in refluxing benzene. The selenyl ester 19 derived from chrysanthemic acid produces a mixture of the gamma,delta-unsaturated aldehyde 22 and the corresponding dimer 25a on treatment with Bu(3)SnH-AIBN. Furthermore, in the presence of methanol the only product from this reaction was the bis(methyl ester) dimer 25b, thereby lending further credence to the involvement of ketene alkyl radical intermediates in these reactions, and in the aforementioned reactions involving 2,6- and 2,7-diene selenyl esters. Treatment of the cyclopropane selenyl esters and , containing keto- and oxy-group functionality in their side-chains, with Bu(3)SnH-AIBN led to excellent syntheses of the enol lactone 66 (76%) and the trans-fused bicyclo[6.1.0]nonane 67 (80-95%) respectively.
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Affiliation(s)
- Christopher J Hayes
- School of Chemistry, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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43
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De Boeck B, Harrington-Frost NM, Pattenden G. Tandem cyclisations involving α-ketenyl alkyl radicals. New syntheses of the natural triquinanes pentalenene and modhephene. Org Biomol Chem 2005; 3:340-7. [PMID: 15632977 DOI: 10.1039/b413817c] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New synthetic approaches to the angular and propellane sesquiterpene triquinanes (+/-)-pentalenene 2 and (+/-)-modhephene 3, respectively, are described. The syntheses are based on tandem cyclisations involving alpha-ketene alkyl radical intermediates produced from alpha,beta-unsaturated acyl radical species, as highlighted in Schemes 2 and 4.
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Affiliation(s)
- Benoît De Boeck
- School of Chemistry, The University of Nottingham, Nottingham, NG7 2RD, UK
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44
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Bella AF, Slawin AMZ, Walton JC. Approach to 3-Aminoindolin-2-ones via Oxime Ether Functionalized Carbamoylcyclohexadienes. J Org Chem 2004; 69:5926-33. [PMID: 15373477 DOI: 10.1021/jo049617f] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
O-Benzyloxime ether substituted amidocyclohexadienes were prepared in three steps in good yields from 2-aminoacetophenone. EPR spectroscopic observations and product analyses showed that peroxide-induced decompositions of model compounds led to indolin-2-ones with benzyloxyaminyl substitution at their 3-positions. The cyclization steps were very rapid and took place regioselectively at the C-atoms of the C=N bonds, by 5-exo ring closures. An O-trityloxime ether analogue was also prepared. The cyclohexadienyl intermediate smoothly yielded an alkoxylaminyl radical again by rapid 5-exo-cyclization. However, ring closure was quickly followed by another beta-scission step that released the persistent trityl radical and a 3-nitrosoindolin-2-one derivative. EPR spectroscopic evidence showed that the nitroso compound trapped other transient intermediates to afford a series of nitroxides. GC-MS analyses of products formed in reactions including methyl thioglycolate indicated that 1-benzyl-3-methyl-1,3-dihydro-2H-indol-2-one was derived from the indolinone moiety.
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Affiliation(s)
- A Franco Bella
- School of Chemistry, University of St. Andrews, St. Andrews, Fife UK KY16 9ST, Scotland
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45
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Majumdar KC, Basu PK, Mukhopadhyay PP. Formation of five- and six-membered heterocyclic rings under radical cyclisation conditions. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.05.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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46
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Crich D, Yao Q. The 4,6-O-[alpha-(2-(2- iodophenyl)ethylthiocarbonyl)benzylidene] protecting group: stereoselective glycosylation, reductive radical fragmentation, and synthesis of beta-D-rhamnopyranosides and other deoxy sugars. Org Lett 2003; 5:2189-91. [PMID: 12790561 DOI: 10.1021/ol034741r] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[reaction: see text] In the thioglycoside/BSP/Tf(2)O glycosylation method, the 4,6-O-[alpha-(2-(2-iodophenyl)ethylthiocarbonyl)benzylidene] group enforces beta-selectivity in mannopyranosylations. Following glycosylation, treatment with Bu(3)SnH in toluene at reflux affords regioselective, reductive fragmentation to the 6-deoxy-beta-mannosides (beta-rhamnosides). Applied to glucosides, the radical fragmentation provides 6-deoxyglucosides, whereas 4-deoxygalactosides are the preferred products in the galactose series. The radical fragmentation is fully compatible with the presence of benzyl and p-methoxybenzyl ethers and with acetate esters
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Affiliation(s)
- David Crich
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA.
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47
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Benati L, Calestani G, Leardini R, Minozzi M, Nanni D, Spagnolo P, Strazzari S. Generation and intramolecular reactivity of acyl radicals from alkynylthiol esters under reducing tin-free conditions. Org Lett 2003; 5:1313-6. [PMID: 12688747 DOI: 10.1021/ol034252r] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] The radical chain reaction of benzenethiol with alkynylthiol esters provides a new, valuable protocol for the tin-free generation of acyl radicals that arise from intramolecular substitution at sulfur by the initial sulfanylvinyl radicals.
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Affiliation(s)
- Luisa Benati
- Dipartimento di Chimica Organica A. Mangini, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
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48
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Blakskaer P, Høj B, Riber D, Skrydstrup T. SmI2 reduced thioesters as synthons of unstable acyl radicals: direct synthesis of potential protease inhibitors via intermolecular radical addition. J Am Chem Soc 2003; 125:4030-1. [PMID: 12670207 DOI: 10.1021/ja029662+] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aromatic alpha-heterosubstituted thioesters were found to undergo radical 1,4-addition reactions to a series of alpha,beta-unsaturated amides and one ester when subjected to the single electron reducing agent, samarium diiodide, at -78 degrees C. These thioesters derived from alpha-amino acids represent a synthetically useful synthon of unstable acyl radicals. This reaction conveniently provides access to gamma-ketoamides and esters in yields up to 90%, structures that are common in various protease inhibitors derived from peptides. Examples with acryloyl and methacryloyl derivatives of alpha-amino acids and dipeptides lead directly to tri- and tetrapeptide mimetics possessing the gamma-ketoamide functionality. No epimerization was observed with the mild conditions used for these reactions.
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Affiliation(s)
- Peter Blakskaer
- Department of Chemistry, University of Aarhus, Langelandsgade 140, 8000 Aarhus C, Denmark
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49
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Benati L, Leardini R, Minozzi M, Nanni D, Spagnolo P, Strazzari S, Zanardi G. Intramolecular cyclization of acyl radicals onto the azido group: a new radical approach to cyclized lactams. Org Lett 2002; 4:3079-81. [PMID: 12201721 DOI: 10.1021/ol026366t] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Aryl- and alkyl-derived azidoacyl radicals, generated from thiolesters by intramolecular homolytic substitution at the sulfur, can undergo five- and six-membered cyclization onto the azido moiety to give cyclized lactams.
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Affiliation(s)
- Luisa Benati
- Dipartimento di Chimica Organica A. Mangini, Università di Bologna, Viale Risorgimento 4, Italy
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50
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