Formation of a Quaternary Carbon Center through the Pd(0)/PhCOOH-Catalyzed Allylation of Cyclic β-Keto Esters and 1,3-Diketones with Alkynes

Formation of a quaternary carbon center through the allylation of β-keto esters and 1,3-diketones with alkynes is accomplished by the use of Pd(0)/benzoic acid catalyst. Reactions of various cyclic β-keto esters and 1,3-diketones with alkynes in the presence of Pd₂dba₃·CHCl₃ (5 mol %), PPh₃ (40 mol %), and PhCOOH (10 mol %) proceeded at 100 °C in toluene (5 M) to give the corresponding allylation products in high yields in a regio- and stereoselective manner. The possibility of asymmetric allylation is also discussed.