of the respective substituents. From the slope, negative rho values are obtained, suggesting that there is a build-up of positive charge in the transition state. Water plays an important role in the catalytic system for sp(3) C-O bond activation and stabilization of the activated Pd(II) cation species. The catalytic system can be performed using only 2.5 mol% Pd2(dba)3 without the phosphine ligand or
巯基
苯甲酸-
钯(0)配合物通过
水中的(eta(3)-苄基)
钯(II)阳离子对
苄基醇进行S-苄基化反应显示出高催化活性。值得注意的是,这些
钯(0)配合物可以在形成活性(eta(3)-苄基)
钯(II)阳离子配合物,然后进行S-苄基化过程中发挥重要作用。Hammett对各种取代醇进行S-苄基化反应的速率常数的研究表明,log(kX / kH)与各个取代基的sigma(+)值之间具有良好的相关性。从斜率可以得到负rho值,这表明在过渡态中会积聚正电荷。
水在sp(3)CO键活化和活化Pd(II)阳离子物种的稳定化催化体系中起着重要作用。催化系统只能使用2进行。