Asymmetric Synthesis of β‐Ketoamides by Sulfonium Rearrangement

The synthesis of enantioenriched α‐substituted 1,3‑dicarbonyls remains a contemporary challenge in synthesis due to their tendency to undergo racemization via keto‐enol tautomerization. Herein, we report a method to access enantioenriched β‐ketoamides by a chiral sulfinimine‐mediated [3,3]‐sigmatropic sulfonium rearrangement. The transformation displays good chirality transfer, as well as excellent chemoselectivity and functional group tolerance. Diastereoselective reduction of the ketone moiety, also achievable in one‐pot fashion, affords enantioenriched β‑hydroxyamides.