Diastereoselective synthesis of highly functionalized homoallylic amine derivatives via diels-alder adducts of N-sulfinyl dienophiles

Novel methodology for the diastereoselective synthesis of some branched functionalized homoallylic amine derivatives is described. The protocol starts with a 3,6-dihydrothiazine-1-oxide, which is readily obtained in a totally stereospecific manner by the hetero-Diels-Alder cycloaddition of an N-sulfinyl dienophile and a 1,3-diene. Various Grignard reagents have been added to these adducts to afford sulfoxide derivatives which have been manipulated stereoselectively via [2,3]- or [3,3]-sigmatropic rearrangements into branched homoallylic amines potentially useful for further synthetic transformations.