Phenyliodine(III) Diacetate/I 2 ‐Mediated Domino Approach for Pyrrolo[1,4]Thiazines and 1,4‐Thiazines by a One‐Pot Morin Rearrangement of N,S ‐ Acetals

An efficient domino transformation using a phenyliodine(III) diacetate (PIDA)/I 2 combination towards Morin 1,4‐thiazine compounds has been developed starting from N,S ‐ acetals. The latter leads to “one‐step” regioselective methylene insertion without the need for traditional sulfoxide intermediates in good yields. The reaction involves easily accessible N,S ‐ acetals obtained from cost‐effective basic ketones and cysteamine as starting materials. This process ultimately leads to 1,4‐thiazines related to natural product and fused derivatives necessary for further QSAR study.