Allan P. Dishington, Richard E. Douthwaite, Andrew Mortlock, Adriano B. Muccioli and Nigel S. Simpkins
Three-membered cyclic sulfones undergo substitution on treatment with base–electrophile mixtures, such as LDA–Me3SiCl and But–P4 phosphazene base–PhCHO, to give either substituted episulfones or the corresponding alkenes following loss of SO2. The structure of a trisilylated episulfone product, 2a, was determined by X-ray crystallography. In the absence of Me3SiCl, reaction of episulfones with lithium diisopropylamide results in ring-opening to give alkenyl sulfinate intermediates, which can be alkylated to give (E)-alkenyl sulfone products in stereoselective fashion.