N-Formylation of Amines with CO 2 by Inorganic Ligand Support Ni Catalyst

Abstract N-formylation of amines with CO2 is a valuable approach to utilizing CO2 as a C1 source in organic synthesis. Herein we presented a highly efficient N-formylation of amines with CO2 and KBH4 catalyzed by (NH4)4[NiMo6O18(OH)6], which is composed of central Ni(II) core supported by MoVIO6 inorganic ligands, and provided corresponding formamides with good selectivity and yields for various primary and secondary amines under mild conditions. Moreover, primary diamines could also be efficiently formylated to afford diformamides. The catalyst could be recycled for six times without significant decrease in catalytic activity and used in gram-scale synthesis. Finally, the reaction mechanism was presented based on the related literature reports and control experiments.