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Liu et al. Chem Synth 2023;3:11 Chemical Synthesis
DOI: 10.20517/cs.2022.46

Research Article Open Access

Enantioselective synthesis of 3-arylindole

atropisomers via organocatalytic indolization of
iminoquinones

1
1,2
1
1,2
Yu-Wei Liu , Ye-Hui Chen , Jun Kee Cheng , Shao-Hua Xiang , Bin Tan 1,*
1
Shenzhen Grubbs Institute, Department of Chemistry, Southern University of Science and Technology, Shenzhen 518055,
Guangdong, China.
2
Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen 518055,
Guangdong, China.
* Correspondence to: Prof. Bin Tan, Shenzhen Grubbs Institute, Department of Chemistry, Southern University of Science
and Technology, No. 1088 Xueyuan Avenue, Shenzhen 518055, Guangdong, China. E-mail: tanb@sustech.edu.cn
How to cite this article: Liu YW, Chen YH, Cheng JK, Xiang SH, Tan B. Enantioselective synthesis of 3-arylindole atropisomers
via organocatalytic indolization of iminoquinones. Chem Synth 2023;3:11. https://dx.doi.org/10.20517/cs.2022.46

Received: 31 Dec 2022 First Decision: 9 Feb 2023 Revised: 13 Feb 2023 Accepted: 17 Feb 2023 Published: 27 Feb 2023

Academic Editor: Feng Shi Copy Editor: Ke-Cui Yang Production Editor: Ke-Cui Yang

Abstract
The direct enantioselective construction of axially chiral 3-arylindole frameworks via nucleophilic addition of 2-
substituted indoles to iminoquinones has been achieved with high efficiencies under mild chiral phosphoric acid
(CPA) catalytic conditions. The utility of this method was demonstrated in successful scale-up syntheses without
compromising the product yields and enantioselectivities. The oxidation of products yields axially chiral heteroaryl-
p-quinone monoimine, which could be subjected to structural diversification via addition of nucleophiles.

Keywords: Organocatalysis, iminoquinones, axial chirality, 3-arylindoles

INTRODUCTION
Indole-based compounds are an important class of small organic molecules. They are broadly present as
core structural components in bioactive natural products, organic functional materials and pesticides . As
[1-4]
one of the prominent subclass, axially chiral 3-arylindole and its derivatives are valuable candidates used to
derive bioactive molecules and chiral catalysts [Scheme 1A] . In line with the progression of axial
[9]
[5-8]
chirality chemistry, the design and synthesis of axially chiral 3-arylindole frameworks have also emerged

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