Enhanced Catalytic Properties of Copper in O- and N-Arylation and Vinylation Reactions, Using Phosphorus Dendrimers as Ligands

Abstract

Imino pyridine-capped phosphorus dendrimers were found to strongly enhance the catalytic activity of copper in arylations and vinylations of O- and N-nucleophiles. These reactions could indeed be performed under very mild conditions, often the mildest to date. Interestingly, such performances could not be obtained when using the monomeric imino pyridine chelating ligand alone. To the best of our knowledge, this constitutes a rare example of such a positive dendritic effect in the field of organometallic catalysis.

Phosphorus dendrimers as supports of transition metal catalysts

“…In the case of PhBr, an increase of the efficiency (yield) was observed on going from the monomer 17-M (inefficient) to the third generation 17-Gc 3 (80% yield), illustrating a true positive dendritic effect (Fig. 17B) [58].…”

“…The reaction was carried out with generation 1 to 3, affording the series of dendritic ligands 17-Gc n (Scheme 16) [58].…”

Magnetic Nanoparticle Supported Imino-pyridine Palladium Catalyzed Suzuki Reactions

“…目前虽有一些负载钯-席 夫碱络合物催化 Suzuki 反应的例子, 但反应往往需要高 的钯用量、有毒的有机溶剂或者较长的反应时间才能顺 利进行 [28～31] . 近来, 作为一种新的席夫碱, 亚胺-吡啶 二齿氮、氮配体已成为有机配体无膦化的新选择, 成功 应用于铜催化的碳-氧和碳-氮偶联 [32,33] 以及钯催化的 Heck 反应和烯烃聚合反应 [34,35] . 为了设计更为绿色高 效的非膦型负载钯催化剂, 本文以硅胶包裹的纳米四氧 化三铁为磁性载体, 经长链硅烷化亚胺吡啶配体化学改 性后与钯盐配位, 制备新型磁性纳米粒子负载钯催化 剂, 将其应用于水溶液相的 Suzuki 反应, 并考察了催化 剂的重复使用性能.…”

Molecular and Macromolecular Engineering with Viologens as Building Blocks: Rational Design of Phosphorus–Viologen Dendritic Structures

“…[12] Polycationic phosphorus dendrimers have a strong antiprion activity reducing prion replication both in vitro and in vivo; these dendrimers did not bear any specific therapeutic agents. [13] Among other unique properties of phosphorus dendrimers, [14] their key roles as catalysts in some reactions of industrial interest with a so-called "strong dendritic effect" [15] and their utility in the synthesis of so-called "organic-inorganic hybrid materials" should be noted. [16] In light of these examples on the properties and applications of both viologens and phosphorus dendrimers, which are far from exhaustive, it appeared to us of great interest to develop new methodologies for the preparation of dendrimers by mixing viologen units and phosphorus linkages into the same framework.…”