Oxiranyl radicals, ring opening

Alkenyl epoxides have been analogously used in the synthesis of bicyclic compounds [69]. Addition of a thiyl radical to a suitably protected epoxyketone enolate generated the oxiranyl carbinyl radical which initiated a cascade of uni-molecular steps (i.e. ring-opening, 1,5-radical translocation, 5-exo cyclization, and ejection of the PhS radical) to produce the final enol product in good yield and high diastereoselectivity (equation (31)). The PhS radical-induced fragmentation of alkenyl epoxy silanes has been found to afford a-trimethylsilyl aldehydes [70]. 

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