Asymmetric Synthesis of syn-α-Substituted β-Amino Ketones by Using Sulfinimines and Prochiral Weinreb Amide Enolates

syn-α-Substituted β-amino Weinreb amides are new chiral building blocks for asymmetric synthesis of syn-α-substituted β-amino acids, aldehydes, and ketones and are prepared by addition of prochiral lithium enolates of Weinreb amides to sulfinimines (N-sulfinyl imines).