Synthesis of fused bicyclic rings by tandem radical ring expansion/cyclization: Evaluating competing intramolecular reactions

Article abstract of DOI:10.1016/S0040-4020(98)00467-0

One- and three-carbon 'Dowd-Beckwith' ring expansions of cyclopentanones and cyclohexanones are generally successful, but tandem expansion/cyclization reactions can be compromised by competing processes. An evaluation of the competition between ring expansion, 1,5-hydrogen transfer, and 6-exo cyclization provides information on how to design successful tandem expansion cyclization sequences.