Recycling Pd colloidal catalysts using polymeric phosphine ligands and polyethylene as a solvent
作者:Nilusha Priyadarshani、Jakkrit Suriboot、David E. Bergbreiter
DOI:10.1039/c3gc36932c
日期:——
Polyisobutylene (PIB)-bound azo dyes were prepared from aryl amine terminated polyisobutylene oligomers and used to form palladacycle precatalysts that can be used for catalytic carbon–carbon cross coupling reactions. The catalysts so formed were recyclable using thermomorphic heptane–DMF solutions that are monophasic at 80 °C and biphasic at room temperature. Under these conditions, the Pd catalyst can be recycled but some Pd leaches into the product solution. Using a low melting polyethylene oligomer as a solvent in place of the volatile heptane solvent reduces this leaching by roughly an order of magnitude. Further modification that involves using a second polyisobutylene (PIB)-bound phosphine ligand both increases the activity of the colloidal Pd catalyst and decreases the total Pd leaching by almost two orders of magnitude with 99.88% of the Pd being recovered. In this case, the Pd content in the solution of the product was ca. 0.3 ppm. These two modifications together lead to a much more sustainable strategy for the use of Pd colloidal catalysts in catalytic cross coupling chemistry.
Variable-Temperature NMR Studies of Soluble Polymer-Supported Phosphine−Silver Complexes
作者:David E. Bergbreiter、Yun-Chin Yang
DOI:10.1021/jo902427w
日期:2010.2.5
catalysts’ use. The results in this study show that heptane phase selectively soluble polyisobutylene (PIB)-bound phosphine ligands have essentially identical kinetic behavior when compared to electronically similar isobutyldiphenylphosphine analogues in phosphine coordination and exchange in silver(I) halide complexes. These studies used variable-temperature 31P NMR spectroscopy to probe the silver−phosphine
聚合物作为有机金属催化剂载体的用途已受到广泛关注。然而,由于聚合物配体将催化剂固定化,催化剂反应性有时会改变,并且这种改变的反应性会使这种负载型催化剂的使用变得复杂。这项研究的结果表明,与电子相似的异丁基二苯基膦类似物在卤化银(I)卤化物配合物中的膦配位和交换相比,庚烷相选择性可溶的聚异丁烯(PIB)结合的膦配体具有基本相同的动力学行为。这些研究使用可变温度31用P NMR光谱探测这些聚合和低分子量膦配体的AgI和AgCl络合物的银-膦交换过程。结果表明,基于这些31 P NMR谱随温度的线形分析,PIB-和异丁基二苯基膦-AgX络合物的动力学行为几乎相同。在可变温度31 P NMR光谱中,对极性更强的聚(乙二醇)三芳基膦结合的AgX配合物和电子类似的低分子量AgX配合物的类似研究具有相似的行为。
Development and Application of a Poly(ethylene glycol)-Supported Triarylphosphine Reagent: Expanding the Sphere of Liquid-Phase Organic Synthesis
作者:Frank Sieber、Paul Wentworth、Jonathan D. Toker、Anita D. Wentworth、William A. Metz、Neal N. Reed、Kim D. Janda
DOI:10.1021/jo9903712
日期:1999.7.1
into the utility of poly(ethyleneglycol) (PEG)-supportedtriarylphosphines as functional polymer reagents in liquid-phaseorganic synthesis (LPOS) are being pursued. This report describes the synthesis and NMR characterization of an aryl-alkyl ether-linked PEG-triarylphosphine derivative (2) and its subsequent application in LPOS. The utility of 2 as a mild stoichiometric reagent for ozonide reduction
Exploiting Poly(ethylene glycol) as a Matrix for Liquid-Phase Organic Synthesis
作者:Frank Sieber、Paul Wentworth、Kim Janda
DOI:10.3390/50801018
日期:——
for the Stille reaction.Keywords: soluble polymer, synthesis, poly(ethyleneglycol), triphenyl phosphine, Wittig re-action, Stille reaction.IntroductionFor many years solid polymers have been dominant both as supports for organic reagents and incombinatorial synthesis [1,2]. However, there are concerns associated with the use of insoluble poly-meric derivatives such as lowered reactivity, site-site interactions
作者:Marek Figlus、Albert C. Tarruella、Anastasia Messer、Steven L. Sollis、Richard C. Hartley
DOI:10.1039/c0cc00415d
日期:——
A toolkit of low molecular weight MPEG-supported coupling agents (MIIDQ, MEDCI), reagents for the Mitsunobu reaction (MDEAD, MTPP), an alternative to diazomethane, and scavengers can be used in the solution-phase synthesis of amides, esters and ureas and are easily removed after use by solid-phase extraction (MSPE) using normal silica.