A New Perfluorinated F21-Tp Scorpionate Ligand: Enhanced Alkane Functionalization by Carbene Insertion with (F21-Tp)M Catalysts (M = Cu, Ag)

Abstract

The new tris(indazolyl)borate ligand [F21-Tp4Bo,3CF3]Tl (1) has been prepared and structurally characterized. The reaction of its thalium salt with copper iodide or silver triflate afforded the complexes [F21-Tp4Bo,3CF3]ML (M = Cu, L = NCMe, 2; M = Ag, L = Me2CO, 4), from which the carbonyl adducts [F21-Tp4Bo,3CF3]M(CO) (M = Cu, 3; M = Ag, 5) have also been obtained. Complexes 2−5 have been characterized by spectroscopic and X-ray studies, from which the existence of electron-deficient metal centers could be envisaged. Complexes 2 and 4 have been employed as catalysts for the reaction of alkanes and cycloalkanes with ethyl diazoacetate. The silver complex displays excellent catalytic activity for the insertion of the carbene into the alkane CH bonds. Functionalized products are obtained in high yield (>90%) with low catalyst loadings (0.5%). TON values of 200 have been reached, 10 times higher than any other group 11 metal-based catalyst already reported for this transformation.