title: Synthesis of tetra-substituted imidazoles and 2-imidazolines by Ni(0)-catalyzed dehydrogenation of benzylic-type imines.
abstract: Ni(0)-catalyzed dehydrogenation of benzylic-type imines was performed to yield asymmetrical tetra-substituted imidazoles and 2-imidazolines. This was achieved with a single operational step while maintaining good selectivity and atom economy. The catalytic system shows low to moderate tolerance for fluoro-, trifluoromethyl-, methyl-, and methoxy-substituted benzylic-type imines. In addition, the substitution pattern at the N-heterocyclic products was easily controlled by the appropriate selection of R-groups in the starting organic substrates. Based on experimental observations, we propose a reaction mechanism in which benzylic C(sp(3))-H bond activation and insertion steps play pivotal roles in this nickel-catalyzed organic transformation.
authors.affiliation: Facultad de Química, Universidad Nacional Autónoma de México, Circuito Interior, Ciudad Universitaria, MexicoCity, 04510, Mexico. juvent@unam.mx.
authors.forename: Adrian
authors.initials: A
authors.lastname: Tlahuext-Aca
authors.forename: Oscar
authors.initials: O
authors.lastname: Hernández-Fajardo
authors.forename: Alma
authors.initials: A
authors.lastname: Arévalo
authors.forename: Juventino J
authors.initials: JJ
authors.lastname: García
mesh_terms: D000466:Alkadienes / Q000737:chemistry*; D002384:Catalysis; D007093:Imidazoles / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D009532:Nickel / Q000737:chemistry*; D009943:Organophosphorus Compounds / Q000737:chemistry*
chemical_list: D000466:Alkadienes; D007093:Imidazoles; D007097:Imines; D009943:Organophosphorus Compounds; C439868:1,5-cyclooctadiene; D009532:Nickel; C017424:2-imidazoline