Hydrodehalogenation of organohalides by Et3SiH catalysed by group 4 metal complexes and B(C6F5)3

Abstract

Catalytic hydrodehalogenation (HDH) of aliphatic organohalides such as trifluorotoluenes by Et₃SiH proceeds in the presence of readily available group 4 metal compounds: Cp′₂MX₂ (Cp′ = η⁵-C₅H₅ or η⁵-C₅Me₅; X = F, Cl, or Me; M = Ti, Zr, or Hf), CpTiCl₃ and TiCl₄ with a catalytic amount of B(C₆F₅)₃. The use of metallocenes in combination with the borane activator leads to a better selectivity of the reaction, i.e., suppression of Friedel–Crafts alkylations of arenes.