Hydrogenation and Reductive Amination of Aldehydes using Triphos Ruthenium Catalysts

Abstract

Abstract An air‐stable and readily accessible ruthenium dihydride complex catalyses aldehyde hydrogenation under neutral conditions. A high activity has been shown in a number of examples, and solvent‐free conditions are also applicable, which favours industrial‐scale applications. The catalyst has also been demonstrated to be active at low catalyst loadings for the reductive amination of aldehydes under mildly acidic conditions. A number of examples of chemoselectivity challenges are also presented in which the catalyst does not reduce carbon−halogen groups, alkene or ketone functionality. The advantage of using the pre‐formed complex, Triphos‐Ru(CO)H 2 ( 1 ), over in situ formed catalysts from Triphos and Ru(acac) 3 (acac=acetylacetonate) is also shown in terms of both chemoselectivity and activity, in particular this can be seen if low reaction temperatures are used.