Abstract: A novel diastereoselective route for the synthesis of a-hydroxy-8, y-unsaturated amine derivatives is described. The protocol starts with a 3, 6-dihydrothiazine 1-oxide, which is obtained stereoselectively by a Diels-Alder [4+ 21 cycloaddition of a N-sulfinyl dienophile and a 1, 3-diene of known geometry. Fission of the SN bond of the adduct with a Grignard reagent leads to an allylic sulfoxide which is converted stereoselectively to an allyl alcohol ...