Palladium-Catalyzed Regioselective Domino Cyclization of Cyclohexadienones

A mild
and efficient Pd-catalyzed arylative domino carbocyclization of cyclohexadienone-containing
1,6-enynes is described. The reaction tolerates a variety of functionalized
boronic acids to afford a cis-fused bicyclic framework
containing an α,β-unsaturated ketone with excellent regio-
and diastereoselectivity in good yields. The tandem process proceeds
with β-arylation of propargylic ether followed by conjugate
addition of a vinyl palladium intermediate and subsequent protonolysis
of a palladium enolate.