title: Transition metal-catalyzed [4 + 2 + 2] cycloadditions of bicyclo[2.2.1]hepta-2,5-dienes (norbornadienes) and bicyclo[2.2.2]octa-2,5-dienes.
abstract: The transition-metal-catalyzed [4 + 2 + 2] cycloadditions of norbornadienes, bicyclo[2.2.2]octa-2,5-diene, and benzobarrelene with 1,3-butadienes proceed in excellent yields using cobalt-based catalytic systems. Two key distinctions between these [4 + 2 + 2] cycloadditions and the corresponding transition-metal-catalyzed [2 + 2 +2] reactions of norbornadiene are the requirement of a bimetal catalytic system with a bisphosphine ligand for the former and exclusive regioselectivity in the [4 + 2 + 2] reaction of 2-substituted norbornadienes to produce 1-substituted adducts. These distinctions may indicate two distinct mechanisms for the [4 + 2 + 2] and [2 + 2 + 2] reactions.
authors.affiliation: Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: R
authors.initials: R
authors.lastname: Kiattansakul
authors.forename: B
authors.initials: B
authors.lastname: Ma
authors.forename: J K
authors.initials: JK
authors.lastname: Snyder
mesh_terms: D001952:Bridged-Ring Compounds / Q000737:chemistry; D002384:Catalysis; D006844:Hydrocarbons, Cyclic / Q000737:chemistry; D019216:Metals, Heavy; D009636:Norbornanes / Q000737:chemistry*
chemical_list: D001952:Bridged-Ring Compounds; D006844:Hydrocarbons, Cyclic; D019216:Metals, Heavy; D009636:Norbornanes