1
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Marquès C, Diaba F, Gómez-Bengoa E, Bonjoch J. Synthesis of the ABC Ring of Calyciphylline A-Type Alkaloids by a Stereocontrolled Aldol Cyclization: Formal Synthesis of (±)-Himalensine A. J Org Chem 2022; 87:10516-10522. [PMID: 35862855 PMCID: PMC9881646 DOI: 10.1021/acs.joc.2c01171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A synthetic approach to a functionalized ABC-tricyclic framework of calyciphilline A-type alkaloids, a building block toward this class of alkaloids, is reported. The key synthetic steps involve a radical cyclization to form the hydroindole system and piperidine ring closure through a stereocontrolled aldol cyclization. The resulting alcohol allows the methyl group to be installed in the bowl-shaped azatricyclic structure; this crucial reaction takes place with configuration retention. The synthesis of azatricyclic compound I constitutes a formal synthesis of himalensine A.
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Affiliation(s)
- Clàudia Marquès
- Laboratori de Química Orgànica, Facultat
de Farmàcia, IBUB, Universitat de Barcelona, Av. Joan
XXIII 27-31, 08028-Barcelona, Spain
| | - Faïza Diaba
- Laboratori de Química Orgànica, Facultat
de Farmàcia, IBUB, Universitat de Barcelona, Av. Joan
XXIII 27-31, 08028-Barcelona, Spain,
| | - Enrique Gómez-Bengoa
- Departamento de Química Orgánica I,
Universidad del País Vasco, Manuel Lardizábal
3, 20018 San Sebastián, Spain
| | - Josep Bonjoch
- Laboratori de Química Orgànica, Facultat
de Farmàcia, IBUB, Universitat de Barcelona, Av. Joan
XXIII 27-31, 08028-Barcelona, Spain,
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2
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Wang B, Xu B, Xun W, Guo Y, Zhang J, Qiu FG. A General Strategy for the Construction of Calyciphylline A‐Type Alkaloids: Divergent Total Syntheses of (−)‐Daphenylline and (−)‐Himalensine A. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Bingyang Wang
- Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Bo Xu
- Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Wen Xun
- Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Yiming Guo
- Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Jing Zhang
- Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Fayang G. Qiu
- Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
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3
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Wang B, Xu B, Xun W, Guo Y, Zhang J, Qiu FG. A General Strategy for the Construction of Calyciphylline A-Type Alkaloids: Divergent Total Syntheses of (-)-Daphenylline and (-)-Himalensine A. Angew Chem Int Ed Engl 2021; 60:9439-9443. [PMID: 33569888 DOI: 10.1002/anie.202016212] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 01/31/2021] [Indexed: 12/16/2022]
Abstract
An efficient general strategy for the synthesis of the Daphniphyllum alkaloids via the rapid construction of a common core intermediate has been established, based on which a divergent total synthesis of (-)-daphenylline and (-)-himalensine A has been accomplished in 16 and 19 steps, respectively. The present work features an enantioselective Mg(ClO4 )2 -catalyzed intramolecular amidocyclization to construct the aza-bridged core structure; a Cu-catalyzed intramolecular cyclopropanation and subsequent phosphine-catalyzed Cope-type rearrangement to furnish the himalensine A scaffold; and a one-pot Diels-Alder/aromatization method to assemble the aromatic skeleton of daphenylline.
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Affiliation(s)
- Bingyang Wang
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Bo Xu
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Wen Xun
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yiming Guo
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jing Zhang
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fayang G Qiu
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
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4
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Abstract
Daphnezomines A and B are structurally unusual Daphniphyllum alkaloids that contain a unique aza-adamantane core skeleton. Herein, a modular approach to these alkaloids is presented that exploits a diverse array of reaction strategies. Commencing from a chiral pool terpene-(S)-carvone, the azabicyclo[3.3.1]nonane backbone, which occurs widely in Daphniphyllum alkaloids, was easily accessed through a Sharpless allylic amination and a palladium-catalyzed oxidative cyclization. A protecting group enabled a stereoselective B-alkyl Suzuki-Miyaura coupling sequence and an Fe-mediated hydrogen atom transfer (HAT)-based radical cyclization were then applied to construct C6 and C8 stereocenters. A final epimer locking strategy enabled the assembly of the highly congested aza-adamantane core, thereby achieving the first total synthesis of (-)-daphnezomines A and B in 14 steps.
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Affiliation(s)
- Guangpeng Xu
- College of Life Sciences, Beijing Normal University, Beijing, 100875, China.,National Institute of Biological Sciences (NIBS), Beijing, 102206, China
| | - Jinbao Wu
- National Institute of Biological Sciences (NIBS), Beijing, 102206, China
| | - Luyang Li
- National Institute of Biological Sciences (NIBS), Beijing, 102206, China
| | - Yunan Lu
- National Institute of Biological Sciences (NIBS), Beijing, 102206, China
| | - Chao Li
- National Institute of Biological Sciences (NIBS), Beijing, 102206, China.,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, 100084, China
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5
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Bonjoch J, Diaba F. Radical Reactions in Alkaloid Synthesis: A Perspective from Carbon Radical Precursors. European J Org Chem 2020. [DOI: 10.1002/ejoc.202000391] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Josep Bonjoch
- Laboratori de Química Orgànica Facultat de Farmàcia, IBUB Universitat de Barcelona Av. Joan XXIII s/n 08028 Barcelona Spain
| | - Faiza Diaba
- Laboratori de Química Orgànica Facultat de Farmàcia, IBUB Universitat de Barcelona Av. Joan XXIII s/n 08028 Barcelona Spain
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6
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Heravi MM, Janati F, Zadsirjan V. Applications of Knoevenagel condensation reaction in the total synthesis of natural products. MONATSHEFTE FUR CHEMIE 2020. [DOI: 10.1007/s00706-020-02586-6] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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7
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Du C, Fang J, Chen J, Liu Z, Li H, Wang X, Xie X, She X. Construction of the Tetracyclic Core of Calyciphylline B-Type Daphniphyllum Alkaloids. Org Lett 2019; 21:8718-8721. [PMID: 31613108 DOI: 10.1021/acs.orglett.9b03322] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A double cyclization strategy was developed to construct the common tetracyclic core of calyciphylline B-type alkaloids. Key features of the synthesis included asymmetric Evans alkylation, ring-closing metathesis reaction, intermolecular amidation, intramolecular aza-Michael addition, and aldol condensation reactions. This strategy may be applied to the total syntheses of this type of natural product.
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Affiliation(s)
- Chenglong Du
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , P.R. China
| | - Jing Fang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , P.R. China
| | - Jinyan Chen
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , P.R. China
| | - Zaimin Liu
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , P.R. China
| | - Huilin Li
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , P.R. China
| | - Xiaolei Wang
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , P.R. China
| | - Xingang Xie
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , P.R. China
| | - Xuegong She
- State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering , Lanzhou University , Lanzhou 730000 , P.R. China
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8
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Guo LD, Hu J, Zhang Y, Tu W, Zhang Y, Pu F, Xu J. Enantioselective Total Synthesis of (-)-Caldaphnidine O via a Radical Cyclization Cascade. J Am Chem Soc 2019; 141:13043-13048. [PMID: 31381311 DOI: 10.1021/jacs.9b07558] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The synthetically challenging, diverse chemical skeletons and promising biological profiles of the Daphniphyllum alkaloids have generated intense interest from the synthetic chemistry community. Herein, the first and enantioselective total synthesis of (-)-caldaphnidine O, a complex bukittinggine-type Daphniphyllum alkaloid, is described. The key transformations in this concise approach included an intramolecular aza-Michael addition, a ring expansion reaction sequence, a Sm(II)/Fe(III)-mediated Kagan-Molander coupling, and the rapid formation of the entire hexacyclic ring skeleton of the target molecule via a radical cyclization cascade reaction, which was inspired by an unexpected radical detosylation observed in our recent dapholdhamine B synthesis.
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Affiliation(s)
- Lian-Dong Guo
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , China
| | - Jingping Hu
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , China
| | - Yan Zhang
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , China
| | - Wentong Tu
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , China
| | - Yue Zhang
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , China
| | - Fan Pu
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , China
| | - Jing Xu
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , China
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9
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Guo LD, Hou J, Tu W, Zhang Y, Zhang Y, Chen L, Xu J. Total Synthesis of Dapholdhamine B and Dapholdhamine B Lactone. J Am Chem Soc 2019; 141:11713-11720. [DOI: 10.1021/jacs.9b05641] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Lian-Dong Guo
- Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, China
| | - Jieping Hou
- Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, China
| | - Wentong Tu
- Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, China
| | - Yan Zhang
- Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, China
| | - Yue Zhang
- Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, China
| | - Louxi Chen
- Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, China
| | - Jing Xu
- Department of Chemistry and Shenzhen Grubbs Institute, Southern University of Science and Technology, Shenzhen, China
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10
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Nakamura H, Kawakami M, Tsukano C, Takemoto Y. Concise Construction of the ACDE Ring System of Calyciphylline A Type Alkaloids by a [5+2] Cycloaddition. Chemistry 2019; 25:8701-8704. [PMID: 31063603 DOI: 10.1002/chem.201901690] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Indexed: 12/27/2022]
Abstract
A concise route for construction of the ACDE ring skeleton in calyciphylline A type alkaloids was developed using an intramolecular [5+2] cycloaddition reaction of an oxidopyrylium species bearing a tetrasubstituted olefin. Key to the success of this reaction was the combination of acid and base, which accelerated the construction of this skeleton containing a spiro ring and vicinal quaternary carbon centers. The resultant tricyclic ADE ring compound was converted to an ACDE ring model through C-H oxidation and an aza-Wittig reaction.
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Affiliation(s)
- Hugh Nakamura
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Manami Kawakami
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Chihiro Tsukano
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
| | - Yoshiji Takemoto
- Graduate School of Pharmaceutical Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto, 606-8501, Japan
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11
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Chen Y, Hu J, Guo LD, Tian P, Xu T, Xu J. Synthesis of the Core Structure of Daphnimacropodines. Org Lett 2019; 21:4309-4312. [PMID: 31141376 DOI: 10.1021/acs.orglett.9b01486] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Daphniphyllum alkaloids daphnimacropodines A-C possess a highly congested ring system and share a common tetracyclic ring skeleton. To access the challenging chemical structure of daphnimacropodines, a divergent synthetic approach toward their total synthesis is described. A stereoselective synthesis of the core structure of daphnimacropodines has been achieved from a simple diketone building block. Our approach features an intramolecular carbamate aza-Michael addition and a hydropyrrole synthesis via a Au-catalyzed alkyne hydration followed by an aldol condensation, whereas all the other attempts failed.
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Affiliation(s)
- Yuye Chen
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China.,State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences , University of Macau , Taipa , Macau 999078 , China
| | - Jingping Hu
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China.,School of Chemistry and Chemical Engineering , Harbin Institute of Technology , Harbin , Heilongjiang 150006 , China
| | - Lian-Dong Guo
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China
| | - Peilin Tian
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China
| | - Tianyue Xu
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China
| | - Jing Xu
- Department of Chemistry and Shenzhen Grubbs Institute , Southern University of Science and Technology , Shenzhen , Guangdong 518055 , China
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12
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Chen Y, Hu J, Guo L, Zhong W, Ning C, Xu J. A Concise Total Synthesis of (−)‐Himalensine A. Angew Chem Int Ed Engl 2019; 58:7390-7394. [DOI: 10.1002/anie.201902908] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Indexed: 12/14/2022]
Affiliation(s)
- Yuye Chen
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
- State Key Laboratory of Quality Research in Chinese MedicineInstitute of Chinese Medical SciencesUniversity of Macau China
| | - Jingping Hu
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
- School of Chemistry and Chemical EngineeringHarbin Institute of Technology Harbin Heilongjiang China
| | - Lian‐Dong Guo
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
| | - Weihe Zhong
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
| | - Chengqing Ning
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
- SUSTech Academy for Advanced Interdisciplinary Studies Shenzhen Guangdong China
| | - Jing Xu
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
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13
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Chen Y, Hu J, Guo L, Zhong W, Ning C, Xu J. A Concise Total Synthesis of (−)‐Himalensine A. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201902908] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Yuye Chen
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
- State Key Laboratory of Quality Research in Chinese MedicineInstitute of Chinese Medical SciencesUniversity of Macau China
| | - Jingping Hu
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
- School of Chemistry and Chemical EngineeringHarbin Institute of Technology Harbin Heilongjiang China
| | - Lian‐Dong Guo
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
| | - Weihe Zhong
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
| | - Chengqing Ning
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
- SUSTech Academy for Advanced Interdisciplinary Studies Shenzhen Guangdong China
| | - Jing Xu
- Department of Chemistry and Shenzhen Grubbs InstituteSouthern University of Science and Technology Shenzhen Guangdong China
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14
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Xu B, Wang B, Xun W, Qiu FG. Total Synthesis of (−)‐Daphenylline. Angew Chem Int Ed Engl 2019; 58:5754-5757. [DOI: 10.1002/anie.201902268] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Indexed: 02/04/2023]
Affiliation(s)
- Bo Xu
- State Key Laboratory of Respiratory DiseaseGuangzhou Institutes of Biomedicine and HealthChinese Academy of Sciences 190 Kaiyuan Avenue Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Bingyang Wang
- State Key Laboratory of Respiratory DiseaseGuangzhou Institutes of Biomedicine and HealthChinese Academy of Sciences 190 Kaiyuan Avenue Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Wen Xun
- State Key Laboratory of Respiratory DiseaseGuangzhou Institutes of Biomedicine and HealthChinese Academy of Sciences 190 Kaiyuan Avenue Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Fayang G. Qiu
- State Key Laboratory of Respiratory DiseaseGuangzhou Institutes of Biomedicine and HealthChinese Academy of Sciences 190 Kaiyuan Avenue Guangzhou 510530 China
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15
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Affiliation(s)
- Bo Xu
- State Key Laboratory of Respiratory DiseaseGuangzhou Institutes of Biomedicine and HealthChinese Academy of Sciences 190 Kaiyuan Avenue Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Bingyang Wang
- State Key Laboratory of Respiratory DiseaseGuangzhou Institutes of Biomedicine and HealthChinese Academy of Sciences 190 Kaiyuan Avenue Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Wen Xun
- State Key Laboratory of Respiratory DiseaseGuangzhou Institutes of Biomedicine and HealthChinese Academy of Sciences 190 Kaiyuan Avenue Guangzhou 510530 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Fayang G. Qiu
- State Key Laboratory of Respiratory DiseaseGuangzhou Institutes of Biomedicine and HealthChinese Academy of Sciences 190 Kaiyuan Avenue Guangzhou 510530 China
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16
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Sirinimal HS, Hebert SP, Samala G, Chen H, Rosenhauer GJ, Schlegel HB, Stockdill JL. Synthetic and Computational Study of Tin-Free Reductive Tandem Cyclizations of Neutral Aminyl Radicals. Org Lett 2018; 20:6340-6344. [PMID: 30265551 DOI: 10.1021/acs.orglett.8b02456] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
5- exo, 5- exo Cyclizations of conformationally unbiased propargylic aminyl radicals proceed with excellent yield, chemoselectivity, and diastereoselectivity under tin-free reductive cyclization conditions, regardless of the electronic environments and intermediate radical stabilization resulting from various olefin substituents. These conditions avoid the need for slow addition of initiator and reductant. By contrast, analogous 6- exo, 5- exo cyclizations require substituents capable of intermediate radical stabilization to avoid premature reduction products. These experimental results are corroborated by computations that further establish the reactivity of these aminyl radicals upon exposure to tin-free cyclization conditions.
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Affiliation(s)
- Hansamali S Sirinimal
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
| | - Sebastien P Hebert
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
| | - Ganesh Samala
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
| | - Heng Chen
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
| | - Gregory J Rosenhauer
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
| | - H Bernhard Schlegel
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
| | - Jennifer L Stockdill
- Department of Chemistry , Wayne State University , Detroit , Michigan 48202 , United States
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