Copper-Catalyzed Enantioselective Propargylic Etherification of Propargylic Esters with Alcohols

Enantioselective propargylic etherification of propargylic esters with not only aliphatic alcohols but also phenols in the presence of a catalytic amount of copper-Pybox complex gives the corresponding propargylic ethers in good to high yields with a high to excellent enantioselectivity (up to 99% ee). The result described here provides the first successful example of enantioselective propargylic etherification