Dithio ester thio-Claisen

Allyl vinyl sulfide in dry tetrahydrofuran treated at -78° with 5ec-butyllithium in pentane, then with benzyl bromide at -78° for 0.5 hr. and at -30° for the same period, the resulting crude intermediate dissolved in 3 1 dimethoxyethane-water in the presence of ca. 3 equivalents Ca-carbonate, and refluxed 12 hrs. -> product. Overall Y 62%. F. e. s. K. Oshima et al.. Am. Soc. 95, 2693 (1973) 7-ketoaldehydes via thio-Claisen rearrangement cf. ibid. 95, 4446 y,5-ethylene-carboxylic acid esters via stereospecific dithio ester thio-Claisen-rearrangement cf. ibid. 95, 5803 syntheses via a-alkylation of dihydro-zd -thiopyrans with sec-butyllithium in the presence of TMEDA s. P. L. Stotter and R. E. Hornish, ibid. 95, 4444. 

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