Palladium-Catalyzed α‑Arylation of Vinylogous Esters for the Synthesis of γ,γ-Disubstituted Cyclohexenones

A palladium-catalyzed
α-arylation of cyclic vinylogous esters
to form products that are converted in one step to γ-alkyl-γ-aryl-substituted
cyclohexenones is reported. This Pd-catalyzed reaction proceeds at
room temperature, is generally high-yielding, and uses an amount of
a commercially available catalyst as low as 0.25 mol %. The scope
of aryl bromides is particularly broad, and alkenyl bromides can also
be used. This two-step protocol, comprising α-arylation and
reductive transposition, can be performed in one pot and is applicable
to gram-scale synthesis.