l. Clear trends were observed; the dppp complexes were much more stable than the others, and the phenylpalladium complexes were more stable than their vinylpalladium counterparts. The observed trends fit with the idea that the reductive elimination step in palladium cross-coupling is facilitated by a ligand with a large interchelate angle. The dppr complexes were significantly more labile than their
摘要在-30°C的环境温度下研究了一组原位生成的P 2 PdMeR型配合物的热稳定性,目的是确定
配体咬角与还原反应活性之间的关系。消除。在该系列中,P 2是1,3-(
二苯基膦基)
丙烷(dppp),1,1'-(
二苯基膦基)
二茂铁(dppf)或1,1'-(
二苯基膦基)
钌茂
金属(dppr),R为苯基或E -2-(4-
甲氧基苯基)
乙烯基。观察到明显趋势;dppp配合物比其他配合物稳定得多,苯基
钯配合物比
乙烯基钯配合物更稳定。观察到的趋势符合这样的想法:
钯的交叉偶联中的还原消除步骤是通过具有大的螯合角的
配体来促进的。