title: Preparation of the Core Structure of Aspidosperma and Strychnos Alkaloids from Aryl Azides by a Cascade Radical Cyclization.
abstract: A novel approach to prepare the core structure of Aspidosperma and Strychnos alkaloids is described. The strategy is based on a cyclization cascade involving the formation of quaternary carbon center followed by trapping of the radical intermediate by an aryl azide to build the 5-membered ring of the pyrrolocarbazole system. This reaction is run with triethylborane without the need for any hydrogen atom donor such as a tin hydride or tris(trimethylsilyl)silane, and it furnishes the tetracyclic framework as a single diastereomer. The influence of different N-protecting groups on the starting iodoacetamide has been examined.
authors.affiliation: Universität Bern , Departement für Chemie und Biochemie, Freiestrasse 3, CH-3012 Bern, Switzerland.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Wyler
authors.affiliation: Universität Bern , Departement für Chemie und Biochemie, Freiestrasse 3, CH-3012 Bern, Switzerland.
authors.forename: François
authors.initials: F
authors.lastname: Brucelle
authors.affiliation: Universität Bern , Departement für Chemie und Biochemie, Freiestrasse 3, CH-3012 Bern, Switzerland.
authors.forename: Philippe
authors.initials: P
authors.lastname: Renaud
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D030009:Aspidosperma / Q000737:chemistry*; D001386:Azides / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D026121:Indole Alkaloids / Q000138:chemical synthesis / Q000737:chemistry; D007460:Iodoacetamide / Q000737:chemistry; D015394:Molecular Structure; D011804:Quinolines / Q000138:chemical synthesis / Q000737:chemistry; D013237:Stereoisomerism; D013331:Strychnine / Q000138:chemical synthesis / Q000737:chemistry; D031451:Strychnos / Q000737:chemistry*
chemical_list: D000470:Alkaloids; D001386:Azides; D026121:Indole Alkaloids; D011804:Quinolines; C409672:aspidospermidine; D013331:Strychnine; D007460:Iodoacetamide