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Zhang J, Liu D, Liu S, Ge Y, Lan Y, Chen Y. Visible-Light-Induced Alkoxyl Radicals Enable α-C(sp 3)-H Bond Allylation. iScience 2019; 23:100755. [PMID: 31884167 PMCID: PMC6941871 DOI: 10.1016/j.isci.2019.100755] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/08/2019] [Accepted: 11/27/2019] [Indexed: 11/18/2022] Open
Abstract
The alkoxyl radical is an essential reactive intermediate in mechanistic studies and organic synthesis with hydrogen atom transfer (HAT) reactivity. However, compared with intramolecular 1,5-HAT or intermolecular HAT of alkoxyl radicals, the intramolecular 1,2-HAT reactivity has been limited to theoretical studies and rarely synthetically utilized. Here we report the first selective 1,2-HAT of alkoxyl radicals for α-C(sp3)-H bond allylation of α-carbonyl, α-cyano, α-trifluoromethyl, and benzylic N-alkoxylphthalimides. The mechanistic probing experiments, electron paramagnetic resonance (EPR) studies, and density functional theory (DFT) calculations confirmed the 1,2-HAT reactivity of alkoxyl radicals, and the use of protic solvents lowered the activation energy by up to 10.4 kcal/mol to facilitate the α-C(sp3)-H allylation reaction.
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Affiliation(s)
- Jing Zhang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, 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
| | - Dan Liu
- State Key Laboratory of Bioorganic and Natural Products Chemistry, 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
| | - Song Liu
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China
| | - Yuanyuan Ge
- State Key Laboratory of Bioorganic and Natural Products Chemistry, 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
| | - Yu Lan
- School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030, China; Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, China.
| | - Yiyun Chen
- State Key Laboratory of Bioorganic and Natural Products Chemistry, 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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2
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Zeng H, Yin G, Wei Q, Li D, Wang Y, Hu Y, Hu C, Zou Y. Unprecedented [5.5.5.6]Dioxafenestrane Ring Construction in Fungal Insecticidal Sesquiterpene Biosynthesis. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201813722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Haichun Zeng
- College of Pharmaceutical SciencesSouthwest University Chongqing 400715 China
| | - Guoping Yin
- College of Pharmaceutical SciencesSouthwest University Chongqing 400715 China
| | - Qian Wei
- College of Pharmaceutical SciencesSouthwest University Chongqing 400715 China
| | - Dehai Li
- Laboratory for Marine Drugs and Bioproducts of Qingdao, National Laboratory for Marine Science and Technology Qingdao 266237 China
| | - Yi Wang
- State Key Laboratory of Silkworm Genome BiologySouthwest University Chongqing 400715 China
| | - Youcai Hu
- State Key Laboratory of Bioactive Substance and Function of Natural MedicinesInstitute of Materia MedicaChinese Academy of Medical Sciences & Peking Union Medical College Beijing 100050 China
| | - Changhua Hu
- College of Pharmaceutical SciencesSouthwest University Chongqing 400715 China
| | - Yi Zou
- College of Pharmaceutical SciencesSouthwest University Chongqing 400715 China
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Zeng H, Yin G, Wei Q, Li D, Wang Y, Hu Y, Hu C, Zou Y. Unprecedented [5.5.5.6]Dioxafenestrane Ring Construction in Fungal Insecticidal Sesquiterpene Biosynthesis. Angew Chem Int Ed Engl 2019; 58:6569-6573. [PMID: 30908782 DOI: 10.1002/anie.201813722] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 03/11/2019] [Indexed: 11/09/2022]
Abstract
Fenestranes, a specific class of natural products, contain four fused rings that share a central quaternary carbon atom. The fungal natural product penifulvin A (1) is a potent insecticidal sesquiterpene that features the [5.5.5.6]dioxafenestrane ring. Although the chemical synthesis of 1 has been achieved recently, the enzymes catalysing the cyclization and oxidation of FPP to 1 remain unknown. In this work, we identified a concise pathway that uses only three enzymes to produce 1. A new sesquiterpene cyclase (PeniA) generates the angular triquinane scaffold silphinene (6). A cytochrome P450 (PeniB) and a flavin-dependent monooxygenase (PeniC) catalyse a series of oxidation reactions to transform 6 into 1, including oxidation of the C15 methyl group to a carboxylate moiety, oxidative coupling of the C15 carboxylate and the C1-C2 olefin to form a γ-lactone, and Baeyer-Villiger oxidation to form a δ-lactone. Our results demonstrate the highly concise and efficient ways in which fungal biosynthetic pathways can generate complex sesquiterpene scaffolds.
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Affiliation(s)
- Haichun Zeng
- College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Guoping Yin
- College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Qian Wei
- College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Dehai Li
- Laboratory for Marine Drugs and Bioproducts of Qingdao, National Laboratory for Marine Science and Technology, Qingdao, 266237, China
| | - Yi Wang
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400715, China
| | - Youcai Hu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China
| | - Changhua Hu
- College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
| | - Yi Zou
- College of Pharmaceutical Sciences, Southwest University, Chongqing, 400715, China
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Boudhar A, Charpenay M, Blond G, Suffert J. Fenestranes in Synthesis: Unique and Highly Inspiring Scaffolds. Angew Chem Int Ed Engl 2013; 52:12786-98. [DOI: 10.1002/anie.201304555] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 06/18/2013] [Indexed: 11/10/2022]
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5
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Boudhar A, Charpenay M, Blond G, Suffert J. Fenestrane in der Synthese: einzigartige und inspirierende Grundgerüste. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201304555] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Affiliation(s)
- Reinhart Keese
- Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
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8
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Tellenbröker J, Barth D, Neumann B, Stammler HG, Kuck D. Methoxy-substituted centrohexaindanes through the fenestrane route. Org Biomol Chem 2005; 3:570-1. [PMID: 15703787 DOI: 10.1039/b417837h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tetrahydroxyfenestrindane undergoes HPF6-catalyzed condensation with anisole, 2-methylanisole and the three dimethoxybenzenes to furnish several centrohexaindanes bearing oxyfunctionalization at the opposite ends of one of the three [2,2']-spirobiindane axes.
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Affiliation(s)
- Jörg Tellenbröker
- Fakultat für Chemie, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany
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Aureliano Antunes CS, Bietti M, Lanzalunga O, Salamone M. Photolysis of 1-Alkylcycloalkanols in the Presence of (Diacetoxyiodo)benzene and I2. Intramolecular Selectivity in the β-Scission Reactions of the Intermediate 1-Alkylcycloalkoxyl Radicals. J Org Chem 2004; 69:5281-9. [PMID: 15287771 DOI: 10.1021/jo049524y] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The C-C beta-scission reactions of 1-alkylcycloalkoxyl radicals, generated photochemically by visible light irradiation of CH2Cl2 solutions containing the parent 1-alkylcycloalkanols, (diacetoxy)iodobenzene (DIB), and I2, have been investigated through the analysis of the reaction products. The 1-alkylcycloalkoxyl radicals undergo competition between ring opening and C-alkyl bond cleavage as a function of ring size and of the nature of the alkyl substituent. With the 1-propylcycloheptoxyl, 1-propylcyclooctoxyl,and 1-phenylcyclooctoxyl radicals, formation of products deriving from an intramolecular 1,5-hydrogen atom abstraction reaction from the cycloalkane ring has also been observed. The results are discussed in terms of release of ring strain associated to ring opening, stability of the alkyl radical formed by C-alkyl cleavage, and with cycloheptoxyl and cyclooctoxyl radicals, also in terms of the possibility of achieving a favorable geometry for intramolecular hydrogen atom abstraction.
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Affiliation(s)
- Carla S Aureliano Antunes
- Dipartimento di Scienze e Tecnologie Chimiche, Università "Tor Vergata", Via della Ricerca Scientifica, 1 I-00133 Rome, Italy
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Boto A, Hernández R, Montoya A, Suárez E. Synthesis of alkaloids from aminol derivatives by β-fragmentation of primary alkoxyl radicals. Tetrahedron Lett 2004. [DOI: 10.1016/j.tetlet.2003.12.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Regioselective free radical phenylsulfenation of a non-activated δ-carbon atom by the photolysis of alkyl benzenesulfenate. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(02)01477-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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