Bronste d acid-catalyze d asymmetric dearomatization of indolyl ynamides: practical and enantioselective synthesis of polycyclic indolines

Catalytic asymmetric dearomatization of indoles and alkynes has received much attention in the past decade because this strategy offers an attractive and alternative way for the efficient synthesis of valu-able chiral polycyclic indolines. However, these reactions have been mostly limited to transition-metal catalysts, and the related chiral Bronsted acid catalysis has been scarcely reported. Herein, we disclose a chiral phosphoric acid-catalyzed asymmetric dearomatization of indolyl ynamides by direct activation of alkynes. This metal-free method enables the practical and atom-economical construction of an array of valuable chiral polycyclic indolines in moderate to good yields with high enantioselectivities (c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

In the past decade, catalytic asymmetric dearomatization of indoles and alkynes has been widely studied as an attractive and alternative strategy for the efficient synthesis of valuable chiral polycyclic indolines. However, most of these reactions have been limited to transition-metal catalysts, with few reports on chiral Bronsted acid catalysis. Here, we present a chiral phosphoric acid-catalyzed asymmetric dearomatization of indolyl ynamides via direct activation of alkynes. This metal-free method allows for the practical and atom-economical construction of a range of valuable chiral polycyclic indolines with moderate to good yields and high enantioselectivities.