Intermediates in Spirosulfurane Formations

Abstract Spirosulfuranes can generally be prepared from the corresponding sulfides with halogenating agents or from sulfoxides by intramolecular dehydration. Mechanisms for the formations have been suggested and determined earlier (1979). Recently, intermediates in spirosulfurane formations have been prepared in our laboratory with molecular structures determined by X-ray diffraction methods. The molecular structures obtained are more compatible with the sulfonium salt formula than with the sulfuranium one, although the arrangement of the ligands about the sulfonium center can be described with a slightly or considerably distorted trigonal bipyramidal geometry due to the relatively strong S⊕… O(carbonyl) interactions.