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

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