THE CHELETROPIC FRAGMENTATION OF HYPERVALENT THREE-MEMBERED THIAHETEROCYCLIC INTERMEDIATES

Article abstract of DOI:10.1016/S0040-4020(01)86237-2

Lithio-imidazolium salts 10, generated in-situ from N'N-dimethylimidazolium salts 9, readily undergo sulfonylation with sulfur dioxide, sulfines, N-sulfinylamines, and thiirane.The resulting zwitterionic species 4 fragment thermally to yield the corresponding imidazolium thione 5 with the hypervalent three-membered thiaheterocyclic intermediates 3 connecting 4 and 5 on the reaction surface.The non-linear cheletropic fragmentation of these relatively stable hypervalent sulfuranes appears to be general for this class of compounds (3 or 4), and the experimental results are in accord with theoretical considerations.