Borane-Trimethylamine Complex as a Reducing Agent for Selective Methylation and Formylation of Amines with CO2

We report herein that a borane-trimethylamine complex worked as an efficient reducing agent for the selective methylation and formylation of amines with 1 atm CO2 under metal-free conditions. 6-Amino-2-picoline serves as a highly efficient catalyst for the methylation of various secondary amines, whereas in its absence, the formylation of primary and secondary amines was achieved in high yield with high chemoselectivity. Mechanistic studies suggest that the 6-amino-2-picoline-borane catalytic system operates like an intramolecular frustrated Lewis pair to activate CO2.

Automated summary

The study demonstrates the use of a borane-trimethylamine complex as an efficient reducing agent for selective methylation and formylation of amines with 1 atm CO2 under metal-free conditions. 6-Amino-2-picoline proved to be a highly efficient catalyst for the methylation of various secondary amines. Mechanistic studies indicate that the 6-amino-2-picoline-borane catalytic system operates similarly to an intramolecular frustrated Lewis pair for CO2 activation.