Toward the Combinatorial Synthesis of Polyketide Libraries:  Asymmetric Aldol Reactions with α-Chiral Aldehydes on Solid Support

The viability of performing stereocontrolled aldol additions with α-chiral aldehydes attached by a silyl linker to a hydroxymethylpolystyrene resin is demonstrated for boron and titanium enolates. Subsequent ketone reduction and manipulation on the solid support leads to elaborate stereopentad sequences, as occur in 6-deoxyerythronolide B and discodermolide.