Radical dearomatising spirocyclisations onto the C-2 position of benzofuran and indole

Spirolactams were obtained via an intramolecular radical ipso-type spirocyclisation in benzofuran and indole systems. Alkyl, vinyl and aryl radicals, tethered at the C-2 position of the heterocycle underwent radical cyclisation to produce novel tricyclic partially dearomatised heterocycles in moderate yields. Fragmentation of the furan ring was observed subsequent to spirocyclisation of a vinyl radical onto a benzofuran.