The Glaser reaction mechanism. A DFT study

A detailed mechanism for the Hey modification of the Glaser oxidative coupling of terminal acetylenes has been formulated based on DFT calculations. The mechanism includes Cu(I)/Cu(III)/Cu(II)/Cu(I) catalytic cycle and explains the dioxygen molecule activation mechanism by Cu(I) species to give water molecule as final product of dioxygen reduction. The key step of the reaction mechanism is the oxidation of Cu acetylide by molecular oxygen to form dicopper-dioxo complex with [Cu2(μ-O2)]2+ core. Relatively low activation energies found for the reaction steps support the viability of the formulated mechanism.