Fast Construction of 1,3-Benzothiazepines by Direct Intramolecular Dehydrogenative C-S Bond Formation of Thioamides under Metal-Free Conditions.

The first general protocol for the synthesis of 1,3-benzothiazepine derivatives was established. With the aid of bench-stable hypervalent iodine promoter fluoro-HTIB, these seven-membered heterocycles can be rapidly synthesized from readily available thioamides under air atmosphere and metal-free conditions. The transformation can be completed within 1 min at room temperature and features a broad substrate scope.