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From Thiiranes to Thiocarbonyl S -Sulfides; Recent Results

1989; Taylor & Francis; Volume: 43; Issue: 1-2 Linguagem: Inglês

10.1080/10426508908040279

1563-5325

Rolf Huisgen,

Synthesis and Catalytic Reactions

Abstract A novel nucleophilic catalysis for the desulfurization of thiiranes is described. Triphenyl-thiirane is quantitatively converted to triphenyl-ethylene by some mol% sodium thiophenoxide or other thiolates in DMSO at 35°C. A rapid initial reaction is retarded by the eliminated sulfur leading to a pseudo-first-order reaction under quasi-stationary conditions. The suggested mechanism is based on structure-rate relationships. - The thiolate-catalyzed reaction of cis-2,3-diphenylthiirane is exceptional in furnishing equimolar quantities of cis-stilbene and 3,4,6,7-tetraphenyl-1,2,5-trithiepane (2 diastereoisomers with bilateral symmetry); mechanistic implications - thiolate attack on sulfur or C-atom of thiirane - are discussed. - Desulfurization of 2,2-diphenylthiirane by thiobenzophenone or other thioketones gives access to thiocarbonyl S-sulfides (“thiosulfines”) which are intercepted by 1,3-cycloadditions to activated acetylenes or to thiones.