title: Phenanthrene-fused azo-ene-ynes: synthesis of dibenzo[f,h]cinnoline and dibenzo[e,g]isoindazole derivatives.
abstract: The cyclization reactions of a phenanthreno-fused azo-ene-yne compound have been studied both experimentally and computationally. Experimental results show that this system is prone to dimerization, more so than previously studied naphthalene- and benzene-based analogues. Calculations reveal that pyrazoles and arene-fused pyrazoles strongly stabilize carbenes in the 5-position through "coarctate conjugation", suggesting a stationary concentration of the carbenes/carbenoids during cyclization that is high enough for dimerization.
authors.affiliation: Department of Chemistry, University of Oregon, Eugene, Oregon 97403-1253, United States.
authors.forename: Brian S
authors.initials: BS
authors.lastname: Young
authors.forename: Felix
authors.initials: F
authors.lastname: Köhler
authors.forename: Rainer
authors.initials: R
authors.lastname: Herges
authors.forename: Michael M
authors.initials: MM
authors.lastname: Haley
mesh_terms: D001391:Azo Compounds / Q000032:analysis / Q000138:chemical synthesis*; D001554:Benzene / Q000737:chemistry; D002625:Chemistry, Organic / Q000379:methods*; D003500:Cyclization; D019281:Dimerization; D006574:Heterocyclic Compounds, 2-Ring / Q000032:analysis / Q000138:chemical synthesis*; D007191:Indazoles / Q000032:analysis / Q000138:chemical synthesis*; D009682:Magnetic Resonance Spectroscopy; D008697:Methane / Q000031:analogs & derivatives / Q000737:chemistry; D015394:Molecular Structure; D010616:Phenanthrenes / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D001391:Azo Compounds; D006574:Heterocyclic Compounds, 2-Ring; D007191:Indazoles; D010616:Phenanthrenes; C030011:carbene; C031181:phenanthrene; D001554:Benzene; C476282:cinnoline; D008697:Methane