title: Torquoselectivity induced by lone-pair conjugation in the electrocyclic reactions of 1-azapolyenes.
abstract: Torquoselectivity in the electrocyclic interconversions of 1-azapolyenes and their heterocyclic isomers was investigated theoretically. The ring openings of 1,2-dihydroazete, 1,2-dihydropyridine, and 1,2-dihydroazocine were examined using HF, MP2, and B3LYP calculations. A large preference for inward rotation of the nitrogen lone pair and outward rotation of the N-H group was found for the four- and six-electron systems. No strong preference was observed for the eight-electron system.
authors.affiliation: Department of Chemistry and Biochemistry, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, California 90095-1569, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Walker
authors.forename: B N
authors.initials: BN
authors.lastname: Hietbrink
authors.forename: B E
authors.initials: BE
authors.lastname: Thomas
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: E A
authors.initials: EA
authors.lastname: Kallel
authors.forename: K N
authors.initials: KN
authors.lastname: Houk
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D002121:Calcium Channel Blockers / Q000737:chemistry; D004095:Dihydropyridines / Q000737:chemistry; D004583:Electrons; D008958:Models, Molecular; D011090:Polyenes / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D001372:Aza Compounds; D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D011090:Polyenes; C038806:1,4-dihydropyridine