A direct synthesis of α-(hydroxymethyl) and α-alkyl-vinyl alkyl ketones

Reaction of 2,4-diketoesters 3a–c with aqueous formaldehyde using potassium carbonate solution as base affords the corresponding α-methylene-β-hydroxyalkanones 4a–c which provide a route to α,β-unsaturated alkyl ketones 6a–e via coupling of α-acetoxymethyl alkyl vinyl ketone 5a with Grignard reagents in the presence of a catalytic amount of LiCuBr2 at low temperature.