γ-Oxygenated-α,β-unsaturated sulfones in radical cyclizations and cascade processes

Article abstract of DOI:10.1016/S0040-4020(97)10368-4

A wide variety of radical precursors having the structure of γ-oxygenated-α,β-unsaturated sulfone (substrates 1-4) have been prepared. Both 5-hexenyl and 6-heptenyl radicals, generated by reaction of substrates 1-4 with Bu₃SnH/AIBN, underwent an efficient cyclization via intramolecular addition to the vinyl sulfone moiety. By introduction of a double bond joined to the oxygen at γ-position, a cascade process based on two sequential radical cyclizations took place, affording highly substituted 2-oxa[3.3.0] or 9-oxa[4.3.0] bicyclic compounds.