An efficient synthesis of enantiopure 1,3-benzothiazines has been achieved by reaction of cyclic sulfenamides and alkylpropiolate or tosylacetylene catalyzed by cesium fluoride.
Cyclic sulfenamide: versatile template for the synthesis of 1,4-benzothiazepines
作者:Cédric Spitz、Vincent Reboul、Patrick Metzner
DOI:10.1016/j.tetlet.2011.07.148
日期:2011.11
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 intermediate; or by an α-sulfenylation reaction promoted by diethylamine and a subsequent acid catalyzed condensation reaction.