Treatment of the polyene iodide 3, containing a vinylcyclopropane electrophore, with tris- (trimethylsilyl) silane (TTMSS)-AIBN gave 6 and 7 (2: 1, 65%) resulting from a radical cascade 13-endo macrocyclisation followed by successive 6-exol 5-exo transannular cyclisations. In a similar manner, the iodo vinylcyclopropane 12a underwent triple cyclisation to a mixture of diastereoisomers of the oestrone analogue 14 (∼ 16%), but the ...