Sulphonate esters as sources of sulphonyl radicals; ring-closure reactions of alk-4- and -5-enesulphonyl radicals

Peter N. Culshaw, John C. Walton*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

Alkyl alkanesulphonates and arenesulphonates were found to be useful sources of sulphonyl radicals, particularly for spectroscopic work, when treated with organotin or organosilyl radicals. Allyl, propynyl and penta-2,4-dienyl methanesulphonates gave, however, allyl, propynyl and pentadienyl radicals, respectively. Sulphonyl radicals generated in this way added efficiently to alk-1-enes with electron-releasing substituents, and the EPR spectra of the adduct radicals were recorded. A variety of radical initiation systems were tried on pent-4-enesulphonyl chloride. The pent-4-enesulphonyl radical cyclised mainly in the endo mode to give the six-membered-ring sulphone. Similarly, the hex-5-enesulphonyl radical cyclised to give thiepane 1,1-dioxide, with a seven-membered ring. The cyclohex-2-enylethanesulphonyl radical cyclised mainly in the exo mode to give 2-chloro-9-thiabicyclo[4.3.0]nonane 9,9-dioxide. The mechanisms of these reactions are discussed.

Original languageEnglish
Pages (from-to)1201-1208
Number of pages8
JournalJournal of the Chemical Society, Perkin Transactions 2
Issue number8
Publication statusPublished - 1 Dec 1991

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