AbstractIn this paper we describe the facile and straightforward covalent functionalization of commercially available dendritic poly(propylenimine) and hyper‐branched poly(ethylenimine) with P‐containing functional groups. The P‐functionalized macromolecules have been applied as multivalent ligands in the Pd‐catalyzed allylic substitution reactions (batch and continuous process) using either morpholine or thiophenol as nucleophile. Palladium complexes of all described molecules are active in allylic substitution reactions. The PEI functionalized polymers appear more sensitive to small changes in the P/Pd ratio than the PPI analogues, but form catalysts that are more active. When used in a continuous flow process the macromolecules are completely retained by the nanofiltration membrane, while the catalytic activity decreases with time because of palladium depletion. This is more severe for the allylic thiolation, probably because of the stronger affinity of sulfur for palladium, facilitating palladium leaching.
摘要 本文介绍了用含 P 的官能团对市售树枝状聚(丙烯亚胺)和超支化聚(乙烯亚胺)进行简便直接的共价官能化。含 P 官能团的大分子已作为多价配体应用于以吗啉或噻吩酚为亲核体的钯催化烯丙基取代反应(间歇和连续过程)中。所有所述分子的钯配合物在烯丙基取代反应中都很活跃。与 PPI 类似物相比,PEI 功能化聚合物似乎对 P/Pd 比率的微小变化更为敏感,但形成的催化剂活性更高。在连续流工艺中使用时,大分子会被纳滤膜完全截留,而催化活性则会随着时间的推移而降低,这是因为钯耗竭的缘故。烯丙基硫醇化的情况更为严重,这可能是因为硫与钯的亲和力更强,有利于钯的沥滤。