Rapid Access to Polyketide Scaffolds via Vinylogous Mukaiyama Aldol Reactions.

[reaction: see text]. The use of the Z-configured vinylogous silyl ketene acetals in Mukaiyama aldol reactions is described. Isopropyl alcohol as scavanger and the use of tris(pentafluorophenyl)borane as the Lewis acid are required for obtaining the gamma-alkylated syn-product selectively. In cases of alpha-chiral aldehydes, Felkin-Anh selectivity was observed.