Cobalt-Catalyzed Synthesis of Unsymmetrically N,N-Disubstituted Formamides via Reductive Coupling of Primary Amines and Aldehydes with CO2 and H-2

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/H-2 over a cobalt-based catalytic system composed of CoF2,. P(CH2CH2PPh2)(3) and 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 CO2 hydrogenation, resulting in the formation of NNFA finally.