Selectfluor-Promoted Chemoselective Self-Etherification, Oxidation, and Ritter-Type Amidation of Benzhydrols

The role of in situ generated fluorinated sulfur intermediates, formed through the interaction of the electrophilic fluorine source Selectfluor with sulfur-containing reagents, in the chemoselective transformations of benzhydrols was investigated from a mechanistic perspective. The 1,2-dimethyldisulfide-Selectfluor combination enabled the selective self-etherification of benzhydrols, and this transformation was shown to proceed via benzhydrol-centered reactive intermediates activated by fluorinated sulfur species. Upon increasing the reaction temperature and 1,2-dimethyldisulfide was replaced with carbon disulfide, the reaction pathway was altered, leading to the selective oxidation of benzhydrols to the corresponding benzophenones. Under the same conditions, when nitromethane was employed as the solvent, Ritter-type amidation was achieved via the solvolytic activation of the benzhydrols. Based on control experiments and the effects of reaction parameters, plausible mechanisms for these condition-dependent chemoselective transformations are proposed and discussed.