Reduction of α,β unsaturated carbonyl compounds by Ni2+–BH4−

The reduction of α,β unsaturated carbonyl compounds by sodiumborohydride is catalysed by Ni(bpy)Cl2 (bpy=2,2′-bipyridine). Various carbonyl compounds having the general formula R1CHCHCRO [where R1, R=C6H5, H; p-MeOC6H4,C6H4; p-CH3C6H4, C6H5; (m-OMe)(p-OMe)C6H3, C6H5; C6H5, (CH3)2CH; CH3, H; m-BrC6H4, C6H5] are reduced to corresponding allylicalcohol [R1CHCHCRHOH] at 25°C within half an hour. During these reductions the double bond is partially reduced to give saturated alcohols as minor products having the molecular formula R1CH2CH2CRHOH. The reduction of trans-3-phenyl-2-propenal with NaBH4 and catalytic amounts of Ni(bpy)Cl2 in solvents containing active deuterium (D2O, CD3OD), leads to the partial incorporation of deuterium at the α and γ positions to give CD bonded alcohols.