Two Catalytic Protocols for the Synthesis of CF₂-Containing Quinazolinones via Domino Reaction

Copper-catalyzed and visible-light catalytic difluoroalkylation reactions of N-cyanamide alkenes have been developed. Various α-bromodifluoromethyl substituted esters, amides and heterocycles were employed as the CF₂ source. Both protocols are characterized by medium to high yields, good functional group compatibility, and applicable to gram-scale synthesis. Comparable studies of copper catalysis and photoredox catalysis demonstrate minimal differences between the two protocols. Preliminary mechanism suggest that both transformations involve tandem radical cyclization process.