2.2- Disubstituted 1,3-dithiolane 1-oxides

Lewis acids readily isomerize both 1,3-dioxolanes and 1,3-oxathiolanes in ether solution. The reaction proceeds by coordination with the oxygen atom in the latter case since 1,3-dithiolanes do not isomerize under the same conditions. With trityl carbonium ion, an oxidative cleavage reaction takes place as shown in Scheme 6. Hydride extraction from the 4-position of 2,2-disubstituted 1,3-dioxolanes leads to an a-ketol in a preparatively useful reaction. 1,3-Oxathiolanes are reported to undergo similar cleavage but no mention of products other than regeneration of the ketone has been made (71CC861). Cationic polymerization of 1,3-dioxolane has been initiated by a wide variety of proton acids, Lewis acids and complex catalytic systems. The exact mechanism of the polymerization is still the subject of controversy, as is the structure of the polymer itself. It is unclear if polymerization... 

A series of 2- and 2,5-disubstituted 1,3-dithianes when oxidized in wet MeCN, using Pt electrodes in an undivided cell, provided 1,2-dithiolane-l-oxides selectively and in good yields, as in Eq. (89) [139]. These 1-oxides had not been observed in previous studies, when divided cells were used. 

---