Efficient oxidative coupling of 2,6-disubstituted phenol catalyzed by a dicopper(ii) complex??

Dalton Transactions Pub Date: 2011-11-24 DOI: 10.1039/C1DT11065A

Abstract

Complexation of a rigid multi-pyridine ligand bis(2-pyridyl)-1,8-naphthyridine (bpnp) with [Cu2(TFA)4] (TFA = trifluoroacetate) resulted in the formation of a dinuclear copper(II) complex, namely [Cu2(bpnp)(μ-OH)(TFA)3] (1). This complex has been characterized by X-ray crystallographic, spectroscopic and elemental analyses. Complex 1 is an efficient catalyst for the oxidative coupling of various 2,6-disubstituted phenols with molecular oxygen. Yields and selectivity depend on the reaction conditions employed, the best results being obtained in isopropanol or dioxane at 90 °C with yields of >99%. Mechanistic pathway of the catalysis is discussed.

Graphical abstract: Efficient oxidative coupling of 2,6-disubstituted phenol catalyzed by a dicopper(ii) complex
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