title: Facile transformation of benzocyclobutenones into 2,3-benzodiazepines via 4pi-8pi tandem electrocyclic reactions involving net insertion of diazomethylene compounds.
abstract: Efficient transformations of benzocyclobutenones into 2,3-benzodiazepines by a formal insertion of diazomethylene compounds are described. This sequential process includes nucleophilic addition of diazomethylene anion, oxy-anion accelerated o-quinodimethane formation by an electrocyclic ring-opening reaction, and 8pi-electrocyclization in one-pot under remarkably mild conditions. Intermediary oxy-anion plays an important role for the efficient transformations.
authors.affiliation: Faculty of Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Matsuya
authors.forename: Noriko
authors.initials: N
authors.lastname: Ohsawa
authors.forename: Hideo
authors.initials: H
authors.lastname: Nemoto
mesh_terms: D001569:Benzodiazepines / Q000138:chemical synthesis*; D003978:Diazomethane / Q000031:analogs & derivatives*; D007659:Ketones / Q000737:chemistry*; D011083:Polycyclic Compounds / Q000737:chemistry*
chemical_list: D007659:Ketones; D011083:Polycyclic Compounds; D001569:Benzodiazepines; C079040:benzocyclobutene; D003978:Diazomethane