Thiete 1,1-dioxides ring opening reactions

Base-induced eliminative ring fission, in which both the double bond and the sulfone function take part, has been observed in thiete dioxides . The reaction can be rationalized in terms of initial Michael-type addition to the double bond of the ring vinyl sulfone, followed by a reverse aldol condensation with ring opening. The isolation of the ether 270c in the treatment of 6c with potassium ethoxide (since the transformation 267 268 is not possible in this case) is in agreement with the reaction mechanism outlined in equation 101 . 

Electrolysis of benzothiete sulfone 269 yields the phenylmethanesulfinate anion (major) and the o-toluenesulfinate anion (minor).Thermolysis 618,619 gj. photolysis of thiete 1,1-dioxides proceeds via ring-opening to vinyl sulfines, for example. 288, which have been trapped by reaction with water, phenol,methanol, or norbornenes. These intermediates may recyclize to unsaturated sultines (cyclic sulfinate esters) (e.g., 289) or lose sulfur monoxide to give mainly the trans isomers of a,j3-unsaturated carbonyl compounds (e.g., 290). Mass spectra also indicate the formation of unsaturated sultines. ... 

The thietane ring of the carboxylate derivative 352 is apparently opened by loss of carbon dioxide. possibly via a thiete intermediate. Isonitriles and ynamines effect ring-expansions of 2,4-bis(imino)thietanes, and similar reactions of enamines and ynamines with tris(imino)thietane, 353 have been reported. The nucleophiles — methanol, ethanethiol, and diethylamine — attack the a-carbon atom of 353, which bears the iminosulfonyl group, to give ring-opened products, for example, 353a. The reactions with sodium azide or hydrazoic acid take a different course. ... 

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