Synthesis of arylsulfonyl-substituted indolo[2,1-a]isoquinolin-6(5H)-one derivatives via a TBAI-catalyzed radical cascade cyclization

We have developed a metal-free radical cascade reaction of N-substituted 2-aryl indoles with readily available sulfonyl hydrazides for the rapid construction of arylsulfonyl-substituted indolo[2,1-a]isoquinolin-6(5H)-one derivatives. With the TBAI-TBHP catalytic system, a broad series of structurally diverse indolo[2,1-a]isoquinolin-6(5H)-one derivatives were obtained in moderate to excellent yields. The reaction features mild reaction conditions, operationally easiness, scaled-up feasibility, and high functional-group-tolerance. (C) 2021 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

A metal-free radical cascade reaction was developed for the synthesis of arylsulfonyl-substituted indolo[2,1-a]isoquinolin-6(5H)-one derivatives using readily available sulfonyl hydrazides and N-substituted 2-aryl indoles. The reaction employed a TBAI-TBHP catalytic system and yielded a broad series of structurally diverse derivatives in moderate to excellent yields. The reaction exhibited mild reaction conditions, operational ease, scalability, and high tolerance towards functional groups.