Elimination reactions of cis- and trans-8a-hydroxy-2-thiadecalin 2,2-dioxide with thionyl chloride. Evidence for intermediacy of ion pairs

Abstract

cis- andtrans-8a-Hydroxy-2-thiadecalin 2,2-dioxide react with thionyl chloride to afford mixtures of unsaturated sulphones. The cis-isomer furnishes only the expected three isomeric olefins [Δ^1(8a), Δ^4a(8a), and Δ^8(8a)], whereas the trans-isomer, besides the same unsaturated derivatives, also furnishes, unexpectedly, the isomeric Δ^4a(5)- and Δ^4(4a)-olefins. A mechanism involving the intermediacy of tight ion pairs is suggested.