The Intramolecular, Stereoselective Addition of Sulfoximine Carbanions to α,β-Unsaturated Esters

ortho-Bromocinnamates can be coupled with methyl phenylsulfoximine to afford N-arylsulfoximines in excellent yield. Treatment of these products with an amide base results in a completely stereoselective cyclization to afford enantiomerically pure benzothiazines. This reaction is stereospecific.