One‐Pot Reductive Amination of Aromatic Aldehydes in [Et3NH][HSO4] using Sodium Borohydride and A Mechanistic Investigation using Computational Method

Abstract

AbstractThe reductive amination of aromatic aldehydes and aromatic amines, performed in the Brønsted acidic ionic liquid [Et3NH][HSO4], using sodium borohydride as a reducing agent is reported. In this protocol, the ionic liquid plays a crucial role in efficiently converting aromatic aldehydes to amines in excellent yields, without the formation of side products. In the presence of [Et3NH][HSO4], the imine was generated in situ from the reaction between the aromatic aldehydes and aromatic amines, and underwent smooth reduction with sodium borohydride. This one‐pot synthesis is practically simple and sustainable. The catalyst [Et3NH][HSO4] also has a demonstrably wide applicability, in that it can be used with a variety of aromatic aldehydes and aromatic amines substituted by various electron‐withdrawing and electron‐donating groups. The role of IL [Et3NH][HSO4] in catalytic reductive amination is validated with the help of density functional theory (DFT)‐based computational studies.