Metal-free, photoredox-catalyzed aromatization-driven deconstructive functionalization of spiro-dihydroquinazolinones with α-CF3 alkenes

Abstract

Metal-free, photoredox-catalyzed aromatization-driven deconstructive functionalization of spiro-dihydroquinazolinones with α-CF₃ alkenes is presented. The readily available spiro-dihydroquinazolinones reacted efficiently with α-CF₃ alkenes during photocatalysis to give the gem-difluoroallylated and the CF₃-containing quinazolin-4(3H)-ones in good yields with excellent chemoselectivity. The selectivity depends on the electron effect of substituents in α-CF₃ alkenes. A wide range of four-, five-, six-, seven-, eight- and twelve-membered spiro-dihydroquinazolinones were compatible with this transformation. The protocol is also characterized by the mild and redox-neutral reaction conditions, good functional group compatibility and excellent atom economy. Mechanistic studies revealed that the reaction proceeds via a radical pathway.