Sulfur dioxide reaction with hexatriene

A double nucleophilic substitution reaction on 1,6-dibromohexane with sodium sulfide has been found to give an acceptable yield (59%) of the thiepane (35 equation 62) (81SC409). The reversible 1,6-addition of sulfur dioxide to ds-hexatriene (equation 63) provides a convenient synthetic route to the 2,7-dihydrothiepin 1,1-dioxide (116) (67JA1281). 

The higher homologue of 3-sulfolene, 2,7-dihydrothiepin-l,1-dioxide could be similarly metallated at low temperatures. Reaction with reactive electrophiles followed by extrusion of sulfur dioxide led [549] to the corresponding hexatriene derivatives, as in the stereoselective synthesis of (Z,E)-l,3,5-decatriene (considered as an undecatriene in the publication) shown here. 

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