Catalyst free N-formylation of aromatic and aliphatic amines exploiting reductive formylation of CO(2) using NaBH(4)

Herein, we report a sustainable approach for N-formylation of aromatic as well as aliphatic amines using sodium borohydride and carbon dioxide gas. The developed approach is catalyst free, and does not need pressure or a specialized reaction assembly. The reductive formylation of CO(2) with sodium borohydride generates formoxy borohydride species in situ, as confirmed by (1)H and (11)B NMR spectroscopy. The in situ formation of formoxy borohydride species is prominent in formamide based solvents and is critical for the success of the N-formylation reactions. The formoxy borohydride is also found to promote transamidation reactions as a competitive pathway along with reductive functionalization of CO(2) with amine leading to N-formylation of amines.