Catalytic Hydrodechlorination of Benzyl Chloride Promoted by Rh- N-heterocyclic Carbene Catalysts.

Lázaro, Guillermo; Polo, Víctor; Fernández ‐ Alvarez, Francisco J.; García ‐ Orduña, Pilar; Lahoz, Fernando J.; Iglesias, Manuel; Pérez ‐ TorrENte, Jesús J.; Oro, Luis A.

The rhodium(I) complexes [Rh(Cl)(COD)(R-NHC-(CH2)3Si(O iPr)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 (K tBuO) the formation of mixtures containing toluene together with 17-19 mol % of the CC homocoupling product, namely PhCH2CH2Ph, 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.

HYDRODECHLORINATION; ELIMINATION reactions; HYDROCHLORINATION; BENZYL chloride; CHLORIDES

ChemSusChem, 2015, Vol 8, Issue 3, p495

1864-5631

Academic Journal

10.1002/cssc.201403036