A regioselective addition of nucleophiles to monocyclic 1,2-thiazinylium perchlorate: a novel precursor of 6-substituted 1,2-thiazines

The nucleophilic addition reactions of 4,5-diphenyl-1,2-thiazinylium perchlorate 1 regioselectively proceeded to give 6-alkoxy- 3a–c and 6-alkyl-1,2-thiazines 3e–f, 4f, 3i–j in good to high yields. The Friedel–Crafts type reaction with arenes also afforded 6-aryl adducts 6a–c.