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

초록

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)]Cl-2 and TMEDA in CH3CN under visible-light irradiation, whereas hydrotrifluoroethylated products were synthesized using fac-[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.

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