Silver(I)-Catalyzed Reaction between Pyrazole and Propargyl Acetates: Stereoselective Synthesis of the Scorpionate Ligands (E)‑Allyl-gem-dipyrazoles (ADPs)

The reaction between readily accessible pyrazole and propargyl acetates in the presence of Ag­(I) catalyst yielded a new class of (E)-allyl-gem-dipyrazole scorpionate ligands: 1-aryl-2-N-pyrazolyl allyl acetates and 1,3-dipyrazolyl-3-arylpropene. The reaction showed broad substrate scope, and various functional and protecting groups were tolerated under the reaction conditions. The palladium­(II) scorpionate complex could thus be easily prepared and successfully employed in Suzuki–Miyaura cross-couplings in water.