Diaryl sulfoxides bearing ortho-sulfur substituents react readily with Grignard reagents on the sulfur atom to produce the corresponding phenyl Grignard reagents bearing ortho-sulfur functional group. Furthermore, thianthrene monooxide was found to react with alkyl Grignard reagents affording o, o′-bis-Grignard reagent of diphenyl sulfide which was converted easily to Martin's sulfurane.
[Perozzi, Edmund F.; Michalak, Ronald S.; Figuli, Garret D.; Stevenson III, William H.; Dess, Daniel B.; et al. Journal of Organic Chemistry, 1981 , vol. 46, # 6 p. 1049 - 1053]