Pure Appl. Chem., 2001, Vol. 73, No. 2, pp. 247-250
http://dx.doi.org/10.1351/pac200173020247
Effect of ligands on the divalent palladium- catalyzed carbon-carbon coupling reactions. Highly enantioselective synthesis of optically active g-butyrolactones
Abstract:
In the palladium (II) -catalyzed enyne coupling reactions, the nitrogen-containing ligand plays the same role as the halide ion to inhibit the β-hydride elimination. Employing the pymox or bisoxazoline as ligands, the catalytic asymmetric cyclization of (Z) -4'-acetoxy-2'-butenyl 2-alkynoates initiated by acetoxypalladation was established with high efficiency (up to 92% ee) to afford the optically active γ-butyrolactones.