title: Studies on difficult intramolecular hydroaminations in the context of four syntheses of alkaloid natural products.
abstract: Examples of intramolecular alkene hydroaminations forming six-membered ring systems are rare, especially for systems in which the double bond is disubstituted. Such cyclizations have important synthetic relevance. Herein we report a systematic study of these cyclizations using recently developed Cope-type hydroamination methodologies. Difficult intramolecular alkene hydroaminations were used as key steps in syntheses of 2-epi-pumiliotoxin C, coniine, N-norreticuline and desbromoarborescidine A. This effort required the development of optimized hydroamination conditions to improve the efficiency of the cyclizations. Collectively, our results show that Cope-type cyclizations can be achieved on a variety of challenging substrates and proceed under similar conditions for both N-H and N-substituted hydroxylamines.
authors.affiliation: Centre for Catalysis Research and Innovation, Department of Chemistry, University of Ottawa , 10 Marie-Curie, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dion
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Vincent-Rocan
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Pamela H
authors.initials: PH
authors.lastname: Cebrowski
authors.forename: Marie-Eve
authors.initials: ME
authors.lastname: Lebrun
authors.forename: Jennifer Y
authors.initials: JY
authors.lastname: Pfeiffer
authors.forename: Anne-Catherine
authors.initials: AC
authors.lastname: Bédard
authors.forename: André M
authors.initials: AM
authors.lastname: Beauchemin
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D000586:Amination; D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry; D003500:Cyclization; D006898:Hydroxylamines / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure
chemical_list: D000470:Alkaloids; D001688:Biological Products; D006898:Hydroxylamines