3-Oxo-1,3λ6,4-oxathiazines: A Novel Class of Heterocyclic S,O-Acetals

In this study, two synthetic methods for the synthesis of a hitherto unknown class of heterocyclic diastereo- and enantiopure S,O-acetals are described. Method A involves a chemoselective monohalogenation of sulfoximines and method B a stereoselective ring opening of sulfonimidates with a carbenoid as the key step, both followed by a base-induced cyclization of the S-(halomethyl)sulfoximine intermediates. The absolute configuration of the resulting 3-oxo-1,3λ6,4-oxathiazines has been confirmed by X-ray structural analysis. Furthermore, the first experiments exploring the reactivity of the new compounds are described.