Four- and Five-membered Cyclic Disulphides

The principal methods for synthesising 1,2-dithiolans are surveyed, together with their advantages and disadvantages. Information is given on the geometry of the 1,2-dithiolan ring. The polarography, photolysis, and spectra of 1,2-dithiolans are discussed, and results are given for their polymerisation, reduction, oxidation, and chlorolysis, as well as the removal of a sulphur atom. Data are presented on the biological importance and application of 1,2-dithiolans. The major part of the review is devoted to the chemistry of unsaturated five-membered cyclic disulphides – the 3-thiones, 3-ones, 3-imines, and 3-ylidenes of 1,2-dithiolens – with methods of preparation and both chemical and physical properties. A detailed examination is made of their reactions with electrophilic and nucleophilic reagents, as well as condensations. Fields of practical application of 1,2-dithiolens are surveyed.
The review concludes with 233 references.