Pinacol coupling of aromatic aldehydes and ketones. . An improved method in an aqueous medium

Abstract

Reductive coupling of aromatic aldehydes and ketones leading to 1,2-diols has been achieved with high yield and good diastereoselectivity under environmentally friendly conditions using aluminium powder in the presence of aqueous sodium hydroxide. The notable advantage of the present method seems to be the negligible formation of side products arising mainly due to reduction of the carbonyls to the corresponding alcohols, Cannizzaro reaction and formation of olefins via McMurry coupling. Diaryl ketones have been found to be unreactive under the present conditions. Moreover, the aluminium recovered after the reaction can be reused after washing and drying.