Zn(BH4)2/Al2O3: A new synthetic method for efficient and convenient reduction of organic carbonyl compounds to their corresponding alcohols

Zn(BH4)2 (0.5-2 mmol) in the presence of Al2O3 (1 mmol) reduces varieties of organic carbonyl compounds such as aldehydes, ketones, acyloins, α-diketones and α, β-unsaturated carbonyl compounds to their corresponding alcohols. Reduction reactions were carried out in THF at room temperature in high to excellent yields of products. The chemoselective reduction of aldehydes over ketones was accomplished successfully with this reducing system. In addition, regioselectivity and exclusive 1,2-reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields was accomplished successfully with this reducing system.