1,3,2-Dioxathiolane 2,2-dioxides with ethylene oxide

The 4,5-unsubstituted 1,3,2-dioxathiolane system (7) exists only in the form of its 2-oxide and 2,2-dioxide or their derivatives. 1,3,2-Dioxathiolane 2-oxide (16) represents the parent compound of saturated five-membered cyclic sulfites. It is a colorless, distillable liquid which can be prepared according to the methods shown in Scheme 9. The most convenient laboratory technique is the reaction of ethylene glycol with thionyl chloride <66HC(2l-l)l>. Another possibility is the transesterification of dimethyl sulfite with ethylene glycol (76CRV747). The reaction of ethylene oxide with sulfur dioxide, frequently described in the patent literature (66HC(2l-l)i>, depends on the reaction conditions. It leads either directly... 

Alkyl-substituted 1,3,2-dioxathiolane 2,2-dioxides can be prepared in a similar manner to the parent compound, ethylene sulfate (18) (66HC(2l-l)i) (cf. Scheme 10, Section 4.33.4.2.1). The method of choice is the permanganate oxidation of the corresponding cyclic sulfites (cf. Section 4.33.3.2.3) since the direct reaction of 1,2-diols with sulfuryl chloride often proceeds less smoothly than does the reaction with thionyl chloride. 4,5-Diaryl-l,3,2-dioxathiole 2,2-dioxides of type (186) are obtained by treatment of 9,10-... 

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