Remarkably high diastereoselective exo diels-alder reactivity of 4-vinyl isothiazoline-3-one-1-oxides: The sulphoxide Syn effect

Semi cyclic sulphoxide containing dienes, 4-vinyl- 1,2-isothiazoline-3-one-1-oxides, generated in situ via Stille coupling methodology dimerise with remarkably high diastereoselectivity via an unusual exo syn transition state. X-ray analysis confirms the diastereoselectivity which was predicted by semi-empirical transition state calculations.