title: Catalytic hydrodechlorination of benzyl chloride promoted by Rh-N-heterocyclic carbene catalysts.
abstract: The rhodium(I) complexes [Rh(Cl)(COD)(R-NHC-(CH2 )3 Si(OiPr)3 )] [COD=cyclooctadiene; R=2,6-diisopropylphenyl (1 a); n-butyl (1 b)] are effective catalyst precursors for the homogeneous hydrodechlorination of benzyl chloride using HSiEt3 as hydrogen source. This reaction is selective to the formation of toluene. However, in presence of a stoichiometric amount of potassium tert-butoxide (KtBuO) the formation of mixtures containing toluene together with 17-19 mol % of the C--C homocoupling product, namely PhCH2 CH2 Ph, is observed. A mechanism proposal based on experimental insights and theoretical calculations at the DFT level that allows explanation of the experimental findings is included. Moreover, the heterogeneous catalytic system based on catalyst 1 a supported on MCM-41 has been demonstrated to be effective for the solvent-free hydrodechlorination of benzyl chloride using HSiEt3 and HSiMe(OSiMe3 )2 .
authors.affiliation: Departamento de Química Inorgánica, Instituto de Síntesis Química y Catálisis Homogénea (ISQCH), Universidad de Zaragoza-CSIC, Pl. San Francisco S/N, 50009 Zaragoza (Spain).
authors.forename: Guillermo
authors.initials: G
authors.lastname: Lázaro
authors.forename: Víctor
authors.initials: V
authors.lastname: Polo
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Fernández-Alvarez
authors.forename: Pilar
authors.initials: P
authors.lastname: García-Orduña
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Lahoz
authors.forename: Manuel
authors.initials: M
authors.lastname: Iglesias
authors.forename: Jesús J
authors.initials: JJ
authors.lastname: Pérez-Torrente
authors.forename: Luis A
authors.initials: LA
authors.lastname: Oro
mesh_terms: D001593:Benzyl Compounds / Q000737:chemistry*; D002384:Catalysis; D054879:Halogenation; D006571:Heterocyclic Compounds / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D008697:Methane / Q000031:analogs & derivatives* / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D012238:Rhodium / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry
chemical_list: D001593:Benzyl Compounds; D006571:Heterocyclic Compounds; D012821:Silanes; C030011:carbene; D006859:Hydrogen; C021292:benzyl chloride; D012238:Rhodium; D008697:Methane
keywords: cc homocoupling; heterogeneous catalysis; homogeneous catalysis; hydrodechlorination; rhodium