title: Transition metal-catalyzed hetero-[5 + 2] cycloadditions of cyclopropyl imines and alkynes: dihydroazepines from simple, readily available starting materials.
abstract: The first example of a transition metal-catalyzed hetero-[5 + 2] cycloaddition reaction is described. Use of cyclopropyl imines as five-atom components, an alkyne as a two-carbon component, and a Rh(I) catalyst enables a new route to dihydroazepines. This new hetero-[5 + 2] cycloaddition works well with aldimines, ketimines, and with substituted cyclopropanes and affords the desired dihydroazepines in excellent yields as single regioisomers. Use of serial imine formation/aza-[5 + 2] cycloaddition generates the desired dihydroazepines in one operation from three commercially available starting materials. The reaction has been scaled to give gram quantities of dihydroazepine.
authors.affiliation: Department of Chemistry, Stanford University, Stanford, California 94305-5080, USA. wenderp@stanford.edu
authors.forename: Paul A
authors.initials: PA
authors.lastname: Wender
authors.forename: Torben M
authors.initials: TM
authors.lastname: Pedersen
authors.forename: Marc J C
authors.initials: MJ
authors.lastname: Scanio