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Champagne SE, Chiang CH, Gemmel PM, Brooks CL, Narayan ARH. Biocatalytic Stereoselective Oxidation of 2-Arylindoles. J Am Chem Soc 2024; 146:2728-2735. [PMID: 38237569 PMCID: PMC11214688 DOI: 10.1021/jacs.3c12393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
3-Hydroxyindolenines can be used to access several structural motifs that are featured in natural products and pharmaceutical compounds, yet the chemical synthesis of 3-hydroxyindolenines is complicated by overoxidation, rearrangements, and complex product mixtures. The selectivity possible in enzymatic reactions can overcome these challenges and deliver enantioenriched products. Herein, we present the development of an asymmetric biocatalytic oxidation of 2-arylindole substrates aided by a curated library of flavin-dependent monooxygenases (FDMOs) sampled from an ancestral sequence space, a sequence similarity network, and a deep-learning-based latent space model. From this library of FDMOs, a previously uncharacterized enzyme, Champase, from the Valley fever fungus, Coccidioides immitis strain RS, was found to stereoselectively catalyze the oxidation of a variety of substituted indole substrates. The promiscuity of this enzyme is showcased by the oxidation of a wide variety of substituted 2-arylindoles to afford the respective 3-hydroxyindolenine products in moderate to excellent yields and up to 95:5 er.
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Affiliation(s)
- Sarah E. Champagne
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Chang-Hwa Chiang
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Philipp M. Gemmel
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Charles L. Brooks
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
- Enhanced Program in Biophysics, University of Michigan, Ann Arbor, Michigan 48109, USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Alison R. H. Narayan
- Life Sciences Institute, University of Michigan, Ann Arbor, Michigan 48109, USA
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
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Ren H, Wang RA, Shi J, Song JR, Wu W, Chi Q, Zhang N. Electrochemical bromocyclization enables 3,5-diversification of heterocyclic indolines. Org Biomol Chem 2023; 21:7290-7294. [PMID: 37650516 DOI: 10.1039/d3ob00985h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Electrophilic bromocyclization reactions are widely used as key steps in the synthesis of diverse functionalized tetrahydrofuroindolines and hexahydropyrroloindolines. However, the direct dibromination variants of these reactions for the synthesis of 3,5-dibromoindolines remain undeveloped. Here, we report a protonic-acid-promoted electrooxidative protocol for the dearomative C3,C5-dibromocyclizations of tryptophol and tryptamine derivatives. This electrosynthetic approach, which enables direct selective construction of heterocyclic 3a,5a-dibromoindolines with inexpensive, non-hazardous NaBr as both the electrolyte and Br source, provides a convenient, practical method for the late-stage 3,5-diversification of heterocyclic indolines.
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Affiliation(s)
- Hai Ren
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, P. R. China.
- Natural Products Research Center of Guizhou Province, Guiyang, 550014, P. R. China
| | - Rui-An Wang
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, P. R. China.
- Natural Products Research Center of Guizhou Province, Guiyang, 550014, P. R. China
| | - Jun Shi
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, P. R. China.
- Natural Products Research Center of Guizhou Province, Guiyang, 550014, P. R. China
| | - Jun-Rong Song
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, P. R. China.
- Natural Products Research Center of Guizhou Province, Guiyang, 550014, P. R. China
| | - Wei Wu
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, P. R. China.
- Natural Products Research Center of Guizhou Province, Guiyang, 550014, P. R. China
| | - Qin Chi
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, P. R. China.
- Natural Products Research Center of Guizhou Province, Guiyang, 550014, P. R. China
| | - Ni Zhang
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, Guiyang, 550014, P. R. China.
- Natural Products Research Center of Guizhou Province, Guiyang, 550014, P. R. China
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Wang W, Song JR, Li ZY, Zhong T, Chi Q, Ren H, Pan WD. Copper-catalyzed aerobic oxidative radical alkoxycyclization of tryptamines to access 3-alkoxypyrroloindolines. RSC Adv 2021; 11:18080-18083. [PMID: 35480191 PMCID: PMC9033248 DOI: 10.1039/d1ra02679h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 05/12/2021] [Indexed: 12/15/2022] Open
Abstract
We report a copper-catalyzed alkoxycyclization of tryptamine derivatives with O2 as the sole oxidant, leading to a variety of C3a-alkoxypyrroloindolines in good yields with high diastereoselectivities. This reaction involves an interesting double catalytic cycle in which copper-catalyzed carboamination cyclization is favored to form the C-3 radical pyrrolidinoindoline intermediate, then a copper-catalytic radical alkoxylation reaction proceeds smoothly.
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Affiliation(s)
- Wei Wang
- School of Pharmaceutical Sciences, Guizhou University Huaxi Avenue South Guiyang 550025 P. R. China
| | - Jun-Rong Song
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences Guiyang 550014 China
| | - Zhi-Yao Li
- School of Pharmaceutical Sciences, Guizhou University Huaxi Avenue South Guiyang 550025 P. R. China
| | - Ting Zhong
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences Guiyang 550014 China
| | - Qin Chi
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences Guiyang 550014 China
| | - Hai Ren
- State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences Guiyang 550014 China
| | - Wei-Dong Pan
- School of Pharmaceutical Sciences, Guizhou University Huaxi Avenue South Guiyang 550025 P. R. China .,State Key Laboratory of Functions and Applications of Medicinal Plants, Guizhou Medical University, The Key Laboratory of Chemistry for Natural Products of Guizhou Province and Chinese Academy of Sciences Guiyang 550014 China
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