Chlorination of a Pyrazole Ligand in Vanadium(V)alkoxo Complexes¹

Abstract

VOCl3 reacts with pyrazolylpyridines in the presence of tBuOH to give new six-coordinate vanadium oxoalkoxo complexes. Changing from tBuOH to tBuOOH does not lead to the corresponding tbutylperoxo complexes but to oxidation of Cl-, which finally results in chlorination of the pyrazole fragment of the chelate ligand. These new V(V) complexes catalyze the epoxidation of allylic alcohols and unfunctionalized olefins in the presence of tBuOOH.