. . . . . . . . . . . . "Enantiopure 2-Thioxotetrahydro-1,3-O,N-heterocycles from Carbohydrates. 3. Enantiopure C-4 Chiral Oxazine- and Oxazolidine-2-thiones from 3-Deoxy-3-isothiocyanato Sugars" . . . .