Construction of successive chiral centers adjacent to a chiral tetraalkylated quaternary center using an asymmetric aldol reaction.

The aldol reaction of 2″ with a variety of different aldehydes gave the corresponding β-lactones 4 bearing successive asymmetric centers adjacent to a chiral tetraalkylated quaternary center or the (E)-alkenes 8. The use of electronically neutral or electron-deficient aldehydes led to 4 in excellent yields with high diastereoselectivities, whereas electron-rich aldehydes performed poorly and underwent decarboxylation to afford 8.