Cobalt-Catalyzed Synthesis of Unsymmetrically N,N-Disubstituted Formamides via Reductive Coupling of Primary Amines and Aldehydes with CO2and H2

Herein, a novel route to synthesize unsymmetrically N,N-disubstituted formamides is reported, which is achieved via reductive coupling of primary amine and aldehyde with CO2/H2over a cobalt-based catalytic system composed of CoF2, P(CH2CH2PPh2)3and K2CO3. The mechanism investigation indicates that a secondary amine is formed via hydrogenation of the imine originated from aldehyde and primary amine, which further reacts with HCOOH generated from CO2hydrogenation, resulting in the formation of NNFA finally.