Reactions of Monothiobenzil and its Dimer

Article abstract of DOI:10.1021/jo00199a002

In contrast to the usual formation of monothiobenzil from desyl thiosulfate in a two-phase system involving aqueous sodium hydroxide and methylene chloride, the dimer, 2,4-dibenzoyl-2,4-diphenyl-1,3-dithietane, is obtained in the absence of methylene chloride; and didesyl sulfide is obtained in ethanolic sodium hydroxide-methylene chloride.Thermolysis of monothiobenzil or monothioanisil gives 1,2,3,4-tetraaryl-2-butene-1,4-diones which may be accompanied by benzil or anisil.Monothiobenzil forms an unstable adduct with cyclopentadiene which can be converted to a stable dibromo derivative; it is converted to benzil by treatment with peracide or nitric acid.Dibenzoylstilbene is obtained by thermolysis of the dimer of monothiobenzil or by treatment of the dimer with triphenylphosphine.Treatment of the dimer with Cleland's reagent (2,3-dihydroxy-1,4-butanedithiol) gives didesyl sulfide, and treatment with cyanide ion gives 2-benzoyl-2,4,5-triphenyl-1,3-oxathiole.