Visible-light-induced radical trifluoromethylation/cyclization of alkynes: synthesis of CF3-containing dioxodibenzothiazepines

Abstract

A simple and metal-free photoinduced radical trifluoromethylation/cyclization reaction of alkynes with readily preparable and air-stable trifluoromethyl thianthrenium triflate (TT-CF₃⁺OTf⁻) as the trifluoromethyl source has been developed. This transformation can be carried out without using metal catalysts and strong oxidants, providing an avenue to construct a series of potential pharmaceutically valuable trifluoromethylated dioxodibenzothiazepines under mild conditions. This protocol offers a green strategy for the synthesis of useful CF₃-containing seven-membered N-heterocycles.