Exploring the mechanism of the reductive amination of acetophenones via the Borch approach: the role of the acid catalyst.

The energetic viability of several mechanistic variations of the reductive amination of acetophenones via the Borch approach was re-examined through density functional theory calculations. The crucial involvement of the acid catalyst is evident not only in the elimination of water, but also in the initial nucleophilic step. This role increases with the electron-donating capability of the substituent positioned at the para -position of acetophenone.