An operationally simple and efficient protocol for the transformation of carbonyl compounds to tertiary amines with various secondary amine-boranes is reported. The reaction proceeds at room temperature and requires a short reaction time under mild conditions. The reaction encompasses a broad substrate scope and furnishes good-to-excellent yields of the amines in a chemoselective fashion.

Abstract

Tertiary amines are ubiquitous and play an essential role in organocatalysis, pharmaceuticals, and fine chemicals. Amongst various synthetic procedures known for their synthesis, the reductive amination of carbonyl compounds has been found to be a proficient method. Over the past few decades, different synthetic strategies for reductive amination have been developed. Most of them suffer from the use of transition metals and/or harsh reaction conditions. Herein, we present an efficient, operationally simple protocol for the chemoselective transformation of carbonyl compounds to tertiary amines under benign conditions. The strategy encompasses a broad substrate scope under the metal-free condition at room temperature and does not require any solvent. A detailed mechanistic investigation was performed with the aid of control experiments and computational study to shed light on the reaction pathway.