A Base and Solvent-Free Ruthenium-Catalyzed Alkylation of Amines
journal contributionposted on 30.12.2016, 00:00 by Jeff Joseph A. Celaje, Xingyue Zhang, Forrest Zhang, Lisa Kam, Jessica R. Herron, Travis J. Williams
A (pyridyl)phosphine-ligated ruthenium(II) catalyst is reported for the chemoselective benzylic N-alkylation of amines, via a hydrogen-borrowing mechanism. The catalyst operates under mild conditions, neat, and without a base or other additive. These conditions offer remarkable functional group compatibility for applications in organic synthesis, including reactions involving phenols and anilines, which are very difficult to achieve. Mechanistic studies suggest that, unlike other catalysts for this reaction, the redox steps are fast and reversible while imine formation is slow. We perceive that this is the origin of the selectivity realized with these reaction conditions.