Atom transfer and rearrangement reactions catalyzed by methyltrioxorhenium, MTO

Methyltrioxorhenium (MTO) catalyzes the desulfurization of thiiranes by triphenylphosphine. Enormous enhancement in rate is observed when the catalyst is pretreated with hydrogen sulfide prior to the reaction. Using 2-mercaptomethylthiophenol as a ligand, the author synthesized several model complexes to study the mechanism of this reaction. With suitable model systems, they were able to show that the active catalyst is a Re(V) species. The reactions are highly stereospecific and very tolerant to functional groups. As part of the studies, he synthesized and crystallographically characterized the first examples of neutral terminal and bridging Re(V)sulfidocomplexes. Some of these complexes undergo fast oxygen atom transfer reactions with organic and inorganic oxidants. Studies on these model complexes led them to the discovery that MTO catalyzes the selective oxidation of thiols to disulfides. This report contains the Introduction; ``Chapter 6: Isomerization of Propargylic Alcohols to Enones and Enals Catalyzed by Methylrhenium Trioxide``; and Conclusions.