Preparation of an episulfone

A stirred solution of 2-(2 -iodo-2 -methanesulfonyl)ethyl-2-methyl-5.5-dimethyl-l,3-dioxane (76mg, 0.21 mmol) in dry THF (8ml) at -78°C 

Analogous chemistry has been reported with a-chlorosulfoxides, though much less studied. Initial y-dehydrochlorination yields thiirane S-oxides, but from these intermediates two alternative pathways can occur leading to sulfeiiales and/ot alkenes. The method was shown to be efficient for the synthesis of tetrasubstituted alkenes [417]. 

Another sulfone-based elimination of large applicability was proposed by Julia [418, 419]. Condensation of a metalled phenyl alkyl sulfone with a carbonyl compound, functionalization of the alkoxide and reductive elimination leads to an olefin. 

This method has been reviewed by Kocienski [420J, together with his own fluoride-induced elimination of p-trimethylsilyl sulfones. 

The reductive elimination of 0-hydroxyimidazoyl sulfones by samarium iodide was claimed to be an improved variation of the Julia olefin synthesis [421]. 

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