RuHCl(CO)(PPh3)3-catalyzed reductive dimerization of α,β-unsaturated aldehydes leading to α-hydroxymethyl ketones

The reductive dimerization alpha,beta-unsaturated aldehydes to give saturated ketones was achieved using RuHCl(CO)(PPh3)(3) as a catalyst in the presence of secondary alcohols as hydrogen source. The reaction is likely to proceed via the hydroruthenation of alpha,beta-unsaturated aldehydes followed by atdol reaction of the resultant ruthenium enolates with alpha,beta-unsaturated aldehydes to give unsaturated a-hydroxymethyl ketones, which undergo transfer hydrogenation to give alpha-hydroxymethyl ketones.