Cyclic sulfenamide: Versatile template for the synthesis of 1,4-benzothiazepines

Article abstract of DOI:10.1016/j.tetlet.2011.07.148

Two efficient syntheses of 1,4-benzothiazepines, substituted in the positions 2 and 5, have been achieved either by a ring expansion reaction of cyclic sulfenamides with methylpropiolate or tosylacetylene catalyzed by pyridine, via a postulated allenolate