Towards mild conditions by predictive catalysis via sterics in the Ru-catalyzed hydrogenation of thioesters

The Milstein's reported discovery of hydrogenation of thioesters directly toward thiols and alcohols catalyzed by a Ru-acridine complex has been studied here by DFT calculations to know the origin of the different performance depending on the nature of the substituents. Unveiling the reaction mechanism leads to a deeper understanding of the steric and electronic properties on the nature of the limiting step of the reaction. Steric maps and Conceptual DFT have been the tools to rationalize the reactivity patterns. In addition, the nature of the catalyst has been studied, replacing the substituents on the phosphorous atoms by less sterically demanding groups with the aim to move to milder reaction conditions.