Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

Chuan Yang; Wei Shi; Jian Tian; Lin Guo; Yating Zhao; Wujiong Xia

doi:10.3762/bjoc.20.12

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

Beilstein J Org Chem. 2024 Jan 19:20:118-124. doi: 10.3762/bjoc.20.12. eCollection 2024.

Authors

Chuan Yang^#^{1

2}, Wei Shi^#^{1

2}, Jian Tian², Lin Guo², Yating Zhao¹, Wujiong Xia^{2

3}

Affiliations

¹ College of Chemical and Material Engineering, Quzhou University, Quzhou 324000, China.
² State Key Lab of Urban Water Resource and Environment, School of Science, Harbin Institute of Technology (Shenzhen), Shenzhen, 518055, China.
³ School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China.

^# Contributed equally.

Abstract

A visible-light-promoted research protocol for constructing dihydropyrido[1,2-a]indolone skeletons is herein described proceeding through a cascade cyclization mediated by trifluoromethyl radicals. This method allows the efficient synthesis of various indole derivatives without the need of photocatalysts or transition-metal catalysts. Mechanism experiments indicate that the process involves a radical chain process initiated by the homolysis of Umemoto's reagent. This straightforward method enables a rapid access to heterocycles containing a trifluoromethyl group.

Keywords: cascade reaction; indole derivatives; photocatalysis; radical chain process; trifluoromethylation.

Grants and funding

We are grateful for the financial support from the Science and Technology Plan of Shenzhen (No. JCYJ20210324133001004 and GXWD20220817131550002), the Natural Science Foundation of Guangdong (No. 2020A1515010564), and Guangdong Basic and Applied Basic Research Foundation (No. 2021A1515220069). W.X. is grateful for the Talent Recruitment Project of Guangdong (No. 2019QN01L753). The project was also supported by State Key Laboratory of Urban Water Resource and Environment (Harbin Institute of Technology) (No.2022TS23), and the Open Research Fund of the School of Chemistry and Chemical Engineering, Henan Normal University.