Radical cyclisation of bromomethyldimethylsilyl propynyl ethers; serial radical cyclisations leading to a hydrindene framework from an acyclic substrate, stereoselectively
Vinyl radicals generated from bromomethyldimethylsilyl propargyl ethers have been efficiently engaged in cascades of radicalcyclizations. Through the enchainment of 5-exo-dig-5-(π-endo)-exo-trig-6-endo-trig or 5-exo-dig-5-(π-endo)-exo-trig-6-exo-trig radical processes, hydrindene and a steroid skeleton could be assembled. Appending on the alkyne a suitable chain bearing a dioxolane for 1,5-radical