Bis(diethylamino)(pentafluorophenyl)phosphane - A push-pull phosphane available for coordination

Abstract

A facile large-scale synthesis of the "push-pull"-substituted ligand bis(diethylamino)(pentafluorophenyl)phosphane is reported. A selenophosphorane as well as complexes with CuI and PdCl2, can be formed almost quantitatively from suitable starting materials. The Pd II complex shows a square-planar coordination with significant distortions of the Cl-Pd-Cl moiety in the solid state. In contrast, the phosphane ligand exhibits a large flexibility in the trigonal-planar coordination of the Cu salt, as proven by X-ray crystallography. C-C cross-coupling reactions and 1,3-dipolar cycloadditions have been tested for the PdII and CuI complexes, respectively. Whereas the reactivity of the PdII complex is good at low temperature, the CuI complex reveals remarkable reaction rates at temperatures up to 130 °C. Furthermore, the CuI-catalyzed azide/alkyne 1,3-dipolar cycloaddition was successfully adapted for flow conditions. Unlike their previously reported congeners, "push-pull"-substituted (amino)(fluoroaryl)phosphanes have been made available for reactions at phosphorus includingcoordination to metal centers, which was employed for catalyzing C-C coupling and "click" reactions. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.