Palladium-catalyzed reactions of cyclohexadienones: regioselective cyclizations triggered by alkyne acetoxylation.Org Lett. 2009 Sep 03; 11(17):3998-4000.OL
Regioselective cyclizations of alkyne-tethered cyclohexadienones can be accomplished under palladium catalysis. The cyclization involves an initial Pd-mediated acetoxylation of the alkyne, followed by migratory insertion and protonolysis of the resulting palladium enolate. The predictable regioselectivity of these atom-economical and stereoselective reactions is influenced by developing steric interactions during migratory insertion of a vinyl palladium intermediate.