Exploiting Organocatalysis: Enantioselective Synthesis of Vinyl Glycines by Allylic Sulfimide [2,3] Sigmatropic Rearrangement

Have it both ways: Enantiomerically enriched E vinyl glycines may be accessed from aldehydes in a concise sequence that combines an organocatalytic α sulfenylation, stereoselective olefination, a sulfimidation, and a [2,3] sigmatropic rearrangement (see scheme, Boc=tert-butoxycarbonyl, nHex=n-hexyl). Either enantiomeric series can be accessed by control of the alkene geometry in the olefination step.