Trifluoroethylation of Alkynes: Synthesis of Allylic-CF3 Compounds by Visible-Light Photocatalysis

摘要

Two types of allylic trifluoromethylated compounds were synthesized by reacting alkynes with CF3CH2I using visible-light photocatalysis.Subtle differences in the catalytic system controlled the selectivity of iodotrifluoroethylation and hydrotrifluoroethylation.The iodotrifluoroethylated products were obtained in the presence of [Ru(bpy)3]C12 and TMEDA in CH3CN under visible-light irradiation,whereas hydrotrifluoroethylated products were synthesized usingfac-[Ir(ppy)3] and a mixture of DBU and K2CO3 in DMF.The iodotrifluoroethylation reaction worked particularly well,even at gram-scale,and the synthetic utility of iodotrifluoroethylated products was proved by their coupling reactions,providing complex CF3-containing products.