The first highly enantio- and diastereoselective vinylogous aldol reaction between propionyl acetate-derived Brassard's diene and aldehydes was accomplished by titanium-lithium combined Lewis acid, affording δ-hydroxy-γ-methyl-β-methoxy acrylates. This methodology was utilized in convenient and concise construction of the polypropionate moiety in cystothiazole A and melithiazole C.