Rate and Mechanism of the Oxidative Addition of Vinyl Triflates and Halides to Palladium(0) Complexes in DMF
作者:Anny Jutand、Serge Négri
DOI:10.1021/om030298c
日期:2003.10.1
[(η1-vinyl)Pd(PPh3)2(DMF)]+TfO- complexes are less stable than [(aryl)Pd(PPh3)2(DMF)]+TfO- formed in the oxidative addition of aryl triflates to Pd0(PPh3)4. The rate constant of the oxidative addition of vinyl triflates and bromides to Pd0(PPh3)4 has been determined and compared to that of aryl triflates and halides. The following reactivity orders are established in DMF: vinyl-OTf ≫ vinyl-Br > PhBr and vinyl-OTf ≫ PhOTf
在配位溶剂例如DMF中,快速氧化加成乙烯基三氟甲磺酸酯与Pd 0(PPH 3)4化学计量条件下给出执行的阳离子络合物[(η 1 -乙烯基)的Pd(PPh 3)2(DMF)] + TFO - ,其已被表征通过电导率测量,电喷雾质谱法和NMR光谱学,其分解以vinylphosphonium盐[乙烯基-PPH前3 ] + TFO -和Pd 0络合物。[(η 1 -乙烯基)的Pd(PPh 3)2(DMF)] +TFO -复合物比稳定更少[(芳基)的Pd(PPh 3)2(DMF)] + TFO -形成在氧化加成芳基三氟甲磺酸酯向Pd 0(PPH 3)4。已经确定了乙烯基三氟甲磺酸酯和溴化物向Pd 0(PPh 3)4的氧化加成的速率常数,并将其与芳基三氟甲磺酸酯和卤化物的速率常数进行了比较。在DMF中建立了以下反应顺序:乙烯基-OTf≫乙烯基-Br> PhBr和乙烯基-OTf≫ PhOTf。