| Abstract: | A variety of rearrangement reactions have been documented in the gas phase ion chemistry of styryl sulfoxides and sulfones. The styryl group rearranges from sulfur to oxygen as evidenced by loss of SCH3 from methyl styryl sulfoxide and loss of SOCH3 from the corresponding sulfone. The resulting m/e 119 ion loses carbon monoxide in one fragmentation route and alternatively loses a hydrogen atom from the aromatic nucleus to produce the benzofuran molecule ion via an electrophilic aromatic ring closure reaction. Styryl sulfoxides lose both carbon monoxide and formyl radicals directly from their molecule ions, but the corresponding sulfones do not fragment in this manner. The mechanisms of the above reactions, as well as others, were investigated using substituent and deuterium labeling. The styryl group has been shown to migrate in preference to a phenyl or substituted phenyl group by investigation of the mass spectra of appropriate aryl styryl sulfoxides and sulfones. |
