Fast and chemoselective transfer hydrogenation of aldehydes catalyzed by a terdentate CNN ruthenium complex [RuCl(CNN)(dppb)]

Aromatic, aliphatic and alpha,beta-unsaturated aldehydes are quickly, quantitatively and chemoselectively reduced to primary alcohols with 2-propanol using 0.05-0.01 mol% of the terdentate CNN ruthenium complex RuCl(CNN)(dppb) (1) [HCNN = 6-(4'-methylphenyl)-2-pyridylmethylamine; dppb = Ph2P(CH2)(4)PPh2] in the presence of potassium carbonate (K2CO3; 1-10 mol%) as a weak base, affording TOF values up to 5.0 x 10(5) h(-1).