In the presence of metallic zinc 3-bromopropyne reacts with aldehydes to give homopropynylic alcohols which are converted to the corresponding bromohomopropynylic acetates by acetylation followed by reaction with N-bromosuccinimide and a catalytic quantity of silver acetate; these derivatives are then oxidized to γ-acetoxy-α-ketoesters with osmium tetroxide and tert-butyl hydroperoxide resulting in a convenient four step ...
