Undecorated Cu(OAc)2-Catalyzed C(sp3)-C(sp3) Bond Formation through para-Hydroxy Group Triggered Remote Benzylic C(sp3)-H Bond Functionalization

The undecorated Cu(OAc)(2)-catalyzed para-hydroxy group triggered oxidative coupling of 2,6-disubstituted 4-cresols with fluorinated beta-keto esters or malonates leading to benzylic C(sp(3))-C(sp(3)) bond formation was investigated. This formal double C(sp(3))-H coupling method features mild conditions, atom economy, ligand- and additive-free catalysis, and ambient air as the terminal oxidant. This ecofriendly method allows rapid access to highly functionalized 3-phenylpropanoate derivatives containing fluorinated quaternary carbon-like centers. On the basis of active p-benzoquinone methide intermediates, a plausible mechanism was proposed.