Photocatalytic synthesis of polyfluoroalkylated dihydropyrazoles and tetrahydropyridazines.

A photocatalytic trifluoromethylation/cyclization reaction of N -allyl and N -homoallyl aldehyde hydrazones with trifluoromethyl thianthrenium triflate was developed for the synthesis of trifluoromethylated dihydropyrazoles and tetrahydropyridazines. Besides, PhI(O 2 CCHF 2 ) 2 was employed to realize the construction of difluoromethylated dihydropyrazoles and tetrahydropyridazines. These protocols exhibit a broad substrate scope and good functional group tolerance.