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Trammel GL, Kuniyil R, Crook PF, Liu P, Brown MK. Nickel-Catalyzed Dearomative Arylboration of Indoles: Regioselective Synthesis of C2- and C3-Borylated Indolines. J Am Chem Soc 2021; 143:16502-16511. [PMID: 34582691 PMCID: PMC8781163 DOI: 10.1021/jacs.1c05902] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Indole dearomatization is an important strategy to access indolines: a motif present in a variety of natural products and biologically active molecules. Herein, a method for transition-metal catalyzed regioselective dearomative arylboration of indoles to generate diverse indolines is presented. The method accomplishes intermolecular dearomatization of simple indoles through a migratory insertion pathway on substrates that lack activating or directing groups on the C2- or C3-positions. Synthetically useful C2- and C3-borylated indolines can be accessed through a simple change in N-protecting group in high regio- and diastereoselectivities (up to >40:1 rr and >40:1 dr) from readily available starting materials. Additionally, the origin of regioselectivity was explored experimentally and computationally to uncover the remarkable interplay between carbonyl orientation of the N-protecting group on indole, electronics of the C2-C3 π-bond, and sterics. The method enabled the first enantioselective synthesis of (-)-azamedicarpin.
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Affiliation(s)
- Grace L Trammel
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave, Bloomington, Indiana 47405, United States
| | - Rositha Kuniyil
- Department of Chemistry, University of Pittsburgh, 219 Parkman Ave, Pittsburgh, Pennsylvania 15260, United States
| | - Phillip F Crook
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave, Bloomington, Indiana 47405, United States
| | - Peng Liu
- Department of Chemistry, University of Pittsburgh, 219 Parkman Ave, Pittsburgh, Pennsylvania 15260, United States
| | - M Kevin Brown
- Department of Chemistry, Indiana University, 800 E. Kirkwood Ave, Bloomington, Indiana 47405, United States
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Huang XL, Cheng YZ, Zhang X, You SL. Photoredox-Catalyzed Intermolecular Hydroalkylative Dearomatization of Electron-Deficient Indole Derivatives. Org Lett 2020; 22:9699-9705. [DOI: 10.1021/acs.orglett.0c03759] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Xu-Lun Huang
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China
- School of Physical Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, China
| | - Yuan-Zheng Cheng
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China
| | - Xiao Zhang
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China
- Fujian Key Laboratory of Polymer Science, Fujian Provincial Key Laboratory of Advanced Materials Oriented Chemical Engineering, College of Chemistry and Materials Science, Fujian Normal University, 32 Shangsan Lu, Fuzhou 350007, China
| | - Shu-Li You
- State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China
- School of Physical Science and Technology, ShanghaiTech University, 100 Haike Road, Shanghai 201210, China
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Zuo YJ, Zhong Z, Fan Y, Li X, Chen X, Chang Y, Song R, Fu X, Zhang A, Zhong CM. Copper-catalyzed diastereoselective synthesis of β-boryl-α-quaternary carbon carboxylic esters. Org Biomol Chem 2018; 16:9237-9242. [PMID: 30475365 DOI: 10.1039/c8ob02469c] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cu(i)-Catalyzed diastereoselective carboboration of α-alkyl-substituted α,β-unsaturated carboxylic esters to produce β-boryl-α-quaternary carbon esters was developed. The carbon skeletons of dialkyl sulfates, primary allyl halides, and benzyl bromides were transferred to the α-position of the substrates to provide products in moderate to good yields with a diastereoselectivity of >95% in most cases. Substrates bearing a β-(hetero)aryl substituent gave higher diastereoselectivities than those bearing a linear β-alkyl substituent. The crystal structure of the potassium trifluoroborate derivative shows that the reactions probably go through a copper(i) enolate intermediate and the diastereoselectivity arises from the electrophilic attack of electrophiles to the less hindered side of the enolates.
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Affiliation(s)
- Ya-Jie Zuo
- College of Natural Resources and Environment, Northwest A&F University, Yangling 712100, P. R. China
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