Synthesis of novel piperidyl spirofused benzofurans/benzopyrans by radical cyclization

Several new piperidyl spirofused benzofurans and piperidyl spirofused benzopyrans were synthesized via an intramolecular radical cyclization as the key step. It was found that the yield of the formation of five‐member ring was much higher than that of six‐member ring. In addition, the substituent attached to the benzene ring had almost no effect on the cyclization. J. Heterocyclic Chem.,(2011).