Visible light-induced one-pot synthesis of CF3/CF2-substituted cyclobutene derivatives

Abstract

An efficient one-pot approach for the controllable synthesis of trifluoromethyl/gem-difluoromethylene substituted cyclobutene derivatives has been developed. The mechanism may involve visible light-induced [2+2]-cycloaddition of quinolinones with 1-bromo-1-trifluoromethylethene, followed by base-promoted dehydrobromination, [1,3]-H shift and further dehydrofluorination. A variety of CF₃/CF₂-substituted cyclobutenes that are currently difficult to obtain are afforded in good yields in this protocol, which may find its way into future fluorinated cyclobutene preparation.