Intramolecular addition of benzylic radicals onto ketenimines. Synthesis of 2-alkylindoles.
The inter- and intramolecular addition of free radicals onto ketenimines is studied. All the attempts to add intermolecularly several silicon, oxygen or carbon centered radicals to N-(4-methylphenyl)-C,C-diphenyl ketenimine were unsuccessful. In contrast, the intramolecular addition of benzylic radicals, generated from xanthates, onto the central carbon of a ketenimine function with its N atom linked to the ortho position of the aromatic ring occurred under a variety of reaction conditions. These intramolecular cyclizations provide a novel radical-mediated synthesis of 2-alkylindoles.
Alajarín
Mateo
M
Departamento de Química Orgánica, Facultad de Química, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain.
Vidal
Angel
A
Ortín
María-Mar
MM