title: A formal total synthesis of (+/-)-cephalotaxine using sequential N-acyliminium ion reactions.
abstract: [reaction: see text] Novel synthesis of cephalotaxine 1 based on tertiary N-acyliminium ion chemistry starting from alkynylamide 2 was achieved. The key steps include the preparation of pyrroloisoquinoline 4 from alkynylamide 2, the ring expansion of pyrroloisoquinoline 4 to pyrrolobenzazepine 12, and the construction of cyclopentapyrrolobenzazepine ring system 6, all of which are derived from N-acyliminium ion intermediates.
authors.affiliation: Tokyo University of Pharmacy and Life Science, School of Pharmacy, 1432-1 Horinouchi, Hachiouji, Tokyo 192-0392, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Koseki
authors.forename: Hiroto
authors.initials: H
authors.lastname: Sato
authors.forename: Yumi
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Nagasaka
mesh_terms: D006248:Harringtonines / Q000138:chemical synthesis* / Q000737:chemistry; D000077863:Homoharringtonine; D015394:Molecular Structure
chemical_list: D006248:Harringtonines; D000077863:Homoharringtonine