DBU-Promoted Demethoxylative Thioannulation of Alkynyl Oxime Ethers with Sulfur for the Synthesis of Bisisothiazole-4-yl Disulfides

An efficient synthesis
of bisisothiazole-4-yl disulfides via the
demethoxylative thioannulation of alkynyl oxime ethers with odorless
elemental sulfur has been first developed. This transformation involves
the N–O bond cleavage, the formation of multiple C–S
and N–S bonds, providing an efficient way for constructions
of both isothiazoles and disulfides. Straightforward elaboration of
the products to isothiazole thioethers expands the synthetic utility
of this reaction.