Visible-light-induced tandem difluoroalkylated spirocyclization of N-arylpropiolamides: access to C3-difluoroacetylated spiro[4,5]trienones

Abstract

A visible-light-catalyzed difluoroacetylated spirocyclization of N-arylpropiolamides with ethyl bromodifluoroacetate as a CF₂CO₂Et radical precursor is described. This approach allows the formation of two carbon–carbon bonds and one carbon–oxygen bond in a single reaction through a sequence of C–H oxidative coupling, ipso-cyclization and dearomatization processes. This protocol affords a straightforward route to synthesize CF₂CO₂Et-containing spiro[4.5]trienones in moderate to good yields.