Chiral Phosphoric Acid-Catalyzed C6 Functionalization of 2,3-Disubstituted Indoles for Synthesis of Heterotriarylmethanes

Org Lett. 2021 Apr 2;23(7):2393-2398. doi: 10.1021/acs.orglett.0c04002. Epub 2021 Mar 18.

Abstract

The direct regio- and enantioselective C6 functionalization of 2,3-disubstituted indoles with azadienes has been developed using chiral phosphoric acid as catalyst, providing a convenient approach to synthesize the optically active heterotriarylmethanes with excellent yields, broad substrate scope, and up to 98% ee. Mechanistic studies revealed that N-alkylation of 2,3-disubstituted indoles with azadienes would be reversible, and enantioselective C6 functionalization could be enabled.