One-pot synthesis of cyclobutenecarboxylate derivatives via olefinic C-F bond functionalization of gem-difluoroalkenes

Abstract

A one-pot approach which provides a series of cyclobutenecarboxylates in moderate to excellent yields has been developed. This strategy involves visible light-induced [2+2]-photocycloaddition of quinolinones with 1-bromo-1-trifluoromethylethene, followed by tandem sodium alkoxide-promoted elimination, nucleophilic vinylic substitution and hydrolysis. The in-situ generated gem-difluoroalkene is the key intermediate to achieve this transformation. Excellent functional group compatibility and high regioselectivity render the method flexibility and practicability. It is worthy to note that cyclobutenecarboxylic acid can be easily obtained in this protocol, further demonstrating the synthetic potential of this strategy.