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

A visible-light-catalyzed difluoroacetylated spirocyclization of N -arylpropiolamides with ethyl bromodifluoroacetate as a CF 2 CO 2 Et 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 CF 2 CO 2 Et-containing spiro[4.5]trienones in moderate to good yields.