Photochemical difluoromethylation of alkynes: synthesis of CF2H-substituted seven-membered dioxodibenzothiazepines and dibenzazepines

Abstract

A general and efficient photochemical strategy for difluoromethylation/radical cascade cyclization of alkynes with sodium difluoromethylsulfinate (NaSO₂CF₂H) has been disclosed. This system provides straightforward access to diverse pharmaceutically appealing difluoromethylated dioxodibenzothiazepines and dibenzazepines. The reaction was conducted under mild conditions without using a transition-metal catalyst, which offers a green strategy for the synthesis of valuable difluoromethylated seven-membered N-heterocycles.