Air‐Stable Manganese NNS Pincer Complexes Enable Ketone Reduction at Room Temperature

Abstract

AbstractA series of air‐stable Mn complexes bearing NNS pincer ligands have been synthesized and fully characterized. The activity of the complexes as (transfer) hydrogenation catalysts was investigated in detail, and a variety of ketones (>20 examples) were converted to the corresponding secondary alcohols at room temperature. The synthetic applicability of this class of catalysts is demonstrated by the tolerance of several functional groups including halides, primary amines, nitriles, esters, and nitro‐groups. Moreover, the optimal catalytic system 5c displayed a high chemoselectivity in the presence of other reducible groups such as nitriles, esters, and alkynes. Competitive catalytic experiments with the analogous bidentate NN complex 8 indicated decoordination of the hemilabile thioether‐moiety during formation of the catalytically active hydrido species.