Catalytic Enantioselective Carbon–Oxygen Bond Formation: Phosphine-Catalyzed Synthesis of Benzylic Ethers via the Oxidation of Benzylic C–H Bonds

Benzylic
alcohols and ethers are common subunits in bioactive molecules,
as well as useful intermediates in organic chemistry. In this Communication,
we describe a new approach to the enantioselective synthesis of benzylic
ethers through the chiral phosphine-catalyzed coupling of two readily
available partners, γ-aryl-substituted alkynoates and alcohols,
under mild conditions. In this process, the alkynoate partner undergoes
an internal redox reaction. Specifically, the benzylic position is
oxidized with good enantioselectivity, and the alkyne is reduced to
the alkene.