Syn Selective Vinylogous Mukaiyama Aldol Reaction Using Z,E-Vinylketene N,O-Acetal with Acetals

Stereoselective vinylogous Mukaiyama aldol reactions using the Z,E-vinylketene silyl N,O-acetal possessing a chiral auxiliary, derived from (E)-3-pentenoic acid and l-valine, have been achieved. The reaction proceeded smoothly to give a syn adduct in high stereoselectivity. Since the products possess structures including δ-alkoxy-γ-methyl-α,β-unsaturated imide, this reaction would be applicable to synthesize polyketides in a short procedure.