title: Synthesis of polycyclic aminocyclobutane systems by the rearrangement of N-(ortho-vinylphenyl) 2-azabicyclo[3.1.0]hexane derivatives.
abstract: The acid-catalysed thermal rearrangements of a family of N-aryl 2-azabicyclo[3.1.0]hexanes is described. These substrates, designed in such a way that the aromatic system is conjugated with an alkene group located at the ortho position relative to the nitrogen atom, have been prepared by using an intramolecular Kulinkovich-de Meijere reaction. The rearrangements can then be conducted either under standard thermal conditions or with microwave activation. Depending on the conditions applied and the substitution pattern, dihydroquinoline or polycyclic aminocyclobutane derivatives can be obtained. A mechanistic discussion is provided, with the proposition of the initial protonation of the aminocyclopropane moiety to give an iminium intermediate. By analogy with related intermolecular reactions, the involvement of electrocyclic reactions among the series of elementary steps that follow is put forward.
authors.affiliation: Laboratoire de Synthèse Organique DCSO, UMR 7652 CNRS/Ecole Polytechnique, 91128 Palaiseau Cedex, France.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Wasilewska
authors.forename: Bartosz A
authors.initials: BA
authors.lastname: Woźniak
authors.forename: Gabriel
authors.initials: G
authors.lastname: Doridot
authors.forename: Kamila
authors.initials: K
authors.lastname: Piotrowska
authors.forename: Natalia
authors.initials: N
authors.lastname: Witkowska
authors.forename: Pascal
authors.initials: P
authors.lastname: Retailleau
authors.forename: Yvan
authors.initials: Y
authors.lastname: Six
mesh_terms: D002384:Catalysis; D003503:Cyclobutanes / Q000737:chemistry*; D006586:Hexanes / Q000138:chemical synthesis* / Q000737:chemistry; D056004:Molecular Dynamics Simulation; D013237:Stereoisomerism; D014025:Titanium
chemical_list: D003503:Cyclobutanes; D006586:Hexanes; C026385:n-hexane; D014025:Titanium
keywords: electrocyclic reactions; iminium compounds; microwave chemistry; small ring systems; titanium