Aerobic intramolecular carbon-hydrogen bond oxidation promoted by Cu(I) complexes

The oxidation of C-H bonds by copper centres in enzymes with molecular oxygen takes place in nature under ambient conditions. Herein we report a similar transformation in which under ambient pressure and temperature (1 atm, 25 degrees C) the complex Tp(Ms)Cu(THF) (Tp(Ms) = hydrotris(3-mesityl-pyrazol-1-yl)borate) undergoes the intramolecular oxidation of an alkylic C-H bond with O-2, leading to the formation of a tri-nuclear compound where alkoxy and hydroxyl ligands are bonded to the copper centres, as inferred from X-ray studies. The presence of adventitious Cu(0) derived from the partial decomposition of initial Tp(Ms)Cu (THF) facilitates the formation of such a trinuclear compound. DFT studies support the reaction taking place through a Cu(III) alkoxy-hydroxyl copper intermediate.