Synthesis of 1,4,2-Oxathiazoles via Oxidative Cyclization of Thiohydroximic Acids

An
oxidative formation of 1,4,2-oxathiazoles from readily available
thiohydroximic acids is reported. A variety of alkyl, aryl, and heteroaryl
substituents are well tolerated for both the thiohydroximic acid and
activating fragments, and the reaction has been demonstrated on gram-scale.
This reaction represents the only method currently available to prepare
a diverse set of oxathiazoles and expands the chemistry of C–H
oxidation via appended N–OH functional groups. Finally, we
also demonstrate the rapid preparation of a 1,4,2-oxathiazole analog
of an anticancer lead molecule.