Pyridine-NHC: Effective Ligand in Pd-Catalyzed Cyclopropanation of Esters with Substituted Allyl Carbonates

By consideration of the mechanism of Pd-catalyzed cyclopropanation and allylation, NHC-pyridine compounds were adopted as the ligand in Pd-catalyzed cyclopropanation of esters and monosubstituted allylic reagents. The corresponding cyclopropanes were afforded as major products in moderate to good yields with high cyclopropane/allylation selectivity.