The regio- and stereoselectivities of the reaction of allyl acetates and silyl ketene acetals catalyzed by palladium(0) complexes: a new route to cyclopropane derivatives

Pd(0) complexes of chelating phosphines catalyzed the coupling of allyl acetates and ketene silyl acetals to yield α-allylated carboxylic acid esters. Unexpectedly alkylation of the central carbon atom (C2) of the allyl groups was also observed with concomitant formation of cyclopropane derivatives. In both cases the silyl enolate attacked the allyl group from the side opposite Pd. The yield of the reaction was sensitive to the nature of the ligand coordinated with palladium. The 1,1'-bis(diphenylphosphino) ferrocene-Pd complex was the most effective catalyst