Silver(I)-Catalyzed Reaction between Pyrazole and Propargyl Acetates: Stereoselective Synthesis of the Scorpionate Ligands (<i>E</i>)‑Allyl-<i>gem</i>-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.以易得的吡唑与炔丙基乙酸酯为原料，在银(I)催化剂作用下发生反应，得到一类新型(E)-烯基-偕二吡唑蝎型配体（scorpionate ligand）：1-芳基-2-N-吡唑基乙酸烯丙酯与1,3-二吡唑基-3-芳基丙烯。该反应底物适用范围广泛，多种官能团与保护基在反应条件下均可兼容。由此可便捷制备钯(II)蝎型配合物，并将其成功应用于水相Suzuki-Miyaura交叉偶联反应。