Construction of Successive Chiral Centers Adjacent to a Chiral Tetraalkylated Quaternary Center Using an Asymmetric Aldol Reaction

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