Chemoselective Transfer Hydrogenation of Aldehydes with HCOONH4 Catalyzed by RuCl(CNNPh)(PP) Pincer Complexes

Aldehydes were chemoselectively reduced to primary alcohols by using HCOONH4 as the hydrogen donor through transfer hydrogenation catalyzed by benzo[h]quinoline pincer complexes RuCl(CNNPh)(PP) at substrate to catalyst molar ratios of 2000 to 20 000. This practical reaction performed with aldehydes of commercial‐grade purity in a water/toluene biphasic system afforded alcohols without the formation of condensation or amination side products. A little pinch: Commercial‐grade aldehydes can be reduced to alcohols through transfer hydrogenation with ammonium formate as the hydrogen donor and catalyzed by benzo[h]quinoline pincer ruthenium complexes without the formation of condensation or amination side products.