Copper-catalyzed direct α-alkynylation of ethers under mild conditions

A new method for the direct alpha-alkynylation of ethers C(sp(3))-H bond with terminal alkynes C(sp)-H bond is described in good yields in the presence of a pincer ligand and copper(II) ion under mild conditions. The catalytic reaction is compatible with various functional groups. Investigation of the mechanism indicates a catalytic cycle involving a radical process and the cleavage of ether C(sp(3))-H bond affording the alpha-oxy radical is the rate determining step.