Synthesis of formamides containing unsaturated groups by N-formylation of amines using CO2 with H2

Formamides have wide applications in the industry and have been synthesized using CO2 as a carbon source and H-2 as a reducing agent. However, previous systems required a noble catalyst and high temperature to achieve high efficiency, and the substrate scope was mostly limited to saturated amines. The selective N-formylation of amines containing unsaturated groups using CO2 and H-2 is challenging because the efficient catalysts for the N-formylation are usually very active for hydrogenation of the unsaturated groups. Herein, we achieved for the first time a selective and efficient N-formylation of amines containing unsaturated groups using CO2 and H-2 with a Cu(OAc)(2)-4-dimethylaminopyridine (DMAP) catalytic system. The substrates were converted to the desired formamides, while the unsaturated groups, such as the carbonyl group, the C=C bond, C N bond and the ester group remained. The main reason for the excellent selectivity of the Cu(OAc)(2)-DMAP catalytic system was that it was very active for the N-formylation reaction, but was not active for the hydrogenation of the unsaturated groups.