Ruthenium(II) pincer complexes with oxazoline arms for efficient transfer hydrogenation reactions

Well-defined (PNN)-N-N-N-C pincer ruthenium complexes bearing both strong phosphine and weak oxazoline donors were developed. These easily accessible complexes exhibit significantly better catalytic activity in transfer hydrogenation of ketones compared to their (PNP)-P-3 analogs. These reactions proceed under mild and base-free conditions via protonation-deprotonation of the 'NH' group in the aromatization-dearomatization process. (c) 2012 Elsevier Ltd. All rights reserved.