title: 7-endo selective aryl radical cyclization onto enamides leading to 3-benzazepines: concise construction of a cephalotaxine skeleton.
abstract: Bu3SnH-mediated radical cyclizations of 2-(2-bromophenyl)-N-ethenylacetamide gave 6-exo cyclization product 15 as the major product, whereas N-[2-(2-bromophenyl)ethyl]-N-ethenylamides gave almost exclusively 7-endo cyclization products. These results indicated that the position of the carbonyl group on enamide played an important role in deciding the course of the cyclization. The 7-endo selective cyclization was applied to concise construction of a cephalotaxine skeleton.
authors.affiliation: Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Taniguchi
authors.forename: Atsuko
authors.initials: A
authors.lastname: Ishita
authors.forename: Masahiko
authors.initials: M
authors.lastname: Uchiyama
authors.forename: Osamu
authors.initials: O
authors.lastname: Tamura
authors.forename: Osamu
authors.initials: O
authors.lastname: Muraoka
authors.forename: Genzoh
authors.initials: G
authors.lastname: Tanabe
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ishibashi
mesh_terms: D000577:Amides / Q000138:chemical synthesis*; D001552:Benzazepines / Q000138:chemical synthesis*; D003500:Cyclization; D005609:Free Radicals / Q000138:chemical synthesis / Q000737:chemistry; D006248:Harringtonines / Q000138:chemical synthesis / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D000077863:Homoharringtonine; D015394:Molecular Structure
chemical_list: D000577:Amides; D001552:Benzazepines; D005609:Free Radicals; D006248:Harringtonines; D006571:Heterocyclic Compounds; D000077863:Homoharringtonine