In situ activation of a latent ruthenium-carbene complex in ionic liquid and its application in ring-closing metathesis

Abstract

Catalytically inactive, latent Ru-carboxylate complex 2, which was recently serendipitously isolated, can be activated in situ efficiently in ionic liquids (ILs) with the aid of imidazolium halides or tetrabutylammonium halides. The activity of the in situ activated catalyst was largely dependent on IL anions, imidazolium halides, and terabutylammonium halides. Under the optimal condition of 1.0 mol-% of [bmim][Br] in CH2Cl2/[bmim][SbF 6] (1:1), latent Ru complex 2 was activated in situ to catalyze the ring-closing metathesis of various dienes with conversions of up to > 99%. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.