Palladium-Catalyzed Sc(OTf)₃/Cs₂CO₃-Assisted C-O Cross-Coupling of Vinylidenecyclopropane-Diesters with Phenolic Compounds

We herein describe a method in the synthesis of aryl ether derivatives from a cross-coupling reaction of vinylidenecyclopropane-diesters (VDCP-diesters) with commercially available phenolic compounds for the formation of C-O bond under palladium catalysis and assisted by Sc(OTf)(3)/Cs2CO3. This developed transformation proceeds through a nucleophilic addition at the 2-position of allenic moiety at 50 degrees C for 4.0 h and is compatible with substituents such as bromine, iodine and borate on the phenolic substrates via a zwitterionic pi-propargyl palladium species, affording the desired products in 29% to 95% isolated yields. A plausible reaction mechanism has been also proposed on the basis of control, deuterium labeling experiments and density functional theory (DFT) calculations.