Discovering Copper for Methane C-H Bond Functionalization

The copper complex Tp((CF3)2,Br)Cu(NCMe) (1, Tp((CF3)2,Br) = hydrotris((3,5-bis(trifluoromethyl)-4-bromo)-pyrazol-1-yl)borate) catalyzes the insertion of the CHCO2Et group (from ethyl diazoacetate N2CHCO2Et, EDA) into the C-H bonds of methane, in a homogeneous process that uses supercritical carbon dioxide (scCO(2)) as the reaction medium. Other light alkanes such as ethane, propane, and butane have been also functionalized with this copper based catalyst, in the first example of the derivatization of the series of C-1-C-4 alkanes with this metal and a soluble catalyst.