Halocyclizations of Unsaturated Sulfoximines.

A method for halocyclizations of S-alkenylsulfoximines is reported. When unsaturated NH-sulfoximines are treated with a combination of iodobenzene diacetate and potassium iodide, a transformation to the corresponding five- and six-membered cyclic products occurs providing S-oxides of dihydro isothiazoles and tetrahydro-1,2-thiazines, respectively, in moderate to high yields with good diastereoselectivities and excellent regioselectivities.