Oxazaborolidinone-promoted vinylogous Mukaiyama aldol reactions.

delta-Hydroxy-alpha,beta-unsaturated carbonyl compounds were prepared in one step via the vinylogous Mukaiyama aldol reactions with O,O-silyl ketene acetals. Isopropyl alcohol as additive and tryptophane-based B-phenyloxazaborolidinone were required for obtaining the gamma-alkylated product in high enantioselectivities.