The structure of polymer-supported triphenylphosphine ditriflate: a potentially useful reagent in organic synthesis

The structure of a polymer-supported version of the Hendrickson "POP" reagent, prepared by the reaction of polymer-supported triphenylphosphine oxide 1 with triflic anhydride, is established as an equilibrium mixture of polymer-supported triphenylphosphine ditriflate 3 (delta 79.4 ppm) and polymer-supported phosphonium anhydride 4 (delta 73.3 ppm). The (31)P NMR chemical shift reported previously for 3 is shown to be incorrect.     

Polymer-supported thiobenzophenone: a self-indicating traceless ‘catch and release’ linker for the synthesis of isothiocyanates

The use of a thiobenzophenone as a self-indicating linker in the polymer-supported synthesis of isothiocyanates via a traceless ‘catch and release’ strategy is reported. Isothiocyanates were furnished via 1,3-dipolar cycloaddition of nitrile oxides with the polymer-supported thiobenzophenone linker, followed by Lewis acid-assisted fragmentation of the resulting polymer-supported oxathiazole.     

聚合物支载的硼氢化钠还原剂系统对苯乙酮的不对称还原

聚合物支载硼氢负离子还原剂Na^+[P-COO(BH~3)]^-中的活泼氢原子能用于酮的不对称还原。该试剂中加入带手性碳的羧酸或醇, 反应后生成的还原系统还原苯乙酮。     

DESIGN OF POLYMER—SUPPORTED CHIRAL CATALYSTS

Some structureal factors to the design of polymer-supported Chiral Catalysts are discussed.and some new appraches for designing of polymer-supported catalysts are reviewed in this paper.     

聚合物支载的不对称有机合成

聚合物支载的不对称有机合成比相应的小分子合成体系有独特的优越性。本文综述了近10年来取得了较大进展的聚合物支载的不对称有机合成体系。     

A novel polymer supported approach to nucleoside modification

Polymer-supported O(6)-(benzotriazol-1-yl)inosine derivatives (Pol-I and Pol-dI) have been synthesized reasonably effectively via reaction of nucleoside phosphonium salts with polymer-linked HOBt (Pol-HOBt). In constast to solution chemistry, use of polymer-supported BOP (Pol-BOP) did not lead to efficient nucleoside loading. Presence of the nucleosides on the support could be readily detected by MAS NMR. Exposure of the polymer-supported nucleosides, Pol-I and Pol-dI, to alcohol, phenol, thiol and amine nucleophiles caused cleavage from the support leading directly to the C-6 modified nucleoside analogues. To our knowledge, these are the first examples of the application of such technology for nucleoside modification. Where possible, results of reactions with the polymer-supported nucleosides are compared to those from solution chemistry, providing insight into the differences between the two techniques. These new polymer-supported nucleosides can be conveniently utilized for diversity-oriented synthesis.     

Modification of poly(vinyl chloride) with pendant metal complex for catalytic applications

Poly(vinyl chloride) was modified to develop an alternative support for the preparation of polymer-supported catalysts. Commercially available poly(vinyl chloride) was synthetically modified to a polymer containing pendant primary amino groups. The Schiff-base of salicylaldehyde and the amino polymer were prepared and were used as the ligands in the synthesis of a polymer-supported copper complex. The polymer-supported ligand and catalysts were characterized by various physical methods. The polymer with the pendant copper complex was able to catalyze the one-pot three-component Mannich reaction between aldehydes, ketones and anilines under mild and environmentally friendly conditions. The catalyst can be recovered by simple filtration and is reusable.     

A simple procedure for the polymer-supported N-heterocyclic carbene-rhodium complex via click chemistry: a recyclable catalyst for the addition of arylboronic acids to aldehydes

A novel polymer-supported carbene-rhodium complex was prepared using a simple procedure via click chemistry. This polymer-supported N-heterocyclic carbene-rhodium complex was characterized and used as a catalyst for the addition of arylboronic acids to aldehydes in good to excellent yields.     

Polymer-supported N-heterocyclic carbene-rhodium complex catalyst for the addition of arylboronic acids to aldehydes

A novel polymer-supported N-heterocylic carbene (NHC)-rhodium complex was prepared from chloromethyl polystyrene (CM PS) resin using a simple procedure. This polymer-supported NHC-rhodium complex was used as a catalyst for the addition of arylboronic acids to aldehydes affording arylmethanols in excellent yields.     

One-step synthesis of reusable, polymer-supported tri-alkyl phosphine ligands. Application in Suzuki-Miyaura and alkoxycarbonylation reactions

A simple, efficient one-step route to polystyrene-supported trialkylphosphine ligands is reported. These polymer-supported alkyl phosphine ligands proved to be highly active for Suzuki-Miyaura reactions and in alkoxycarbonylation reactions. The palladium loaded polymer-supported catalysts can be recycled several times with only minimal loss of catalyst activity.     

Polymer-assisted solution-phase (PASP) Suzuki couplings employing an anthracene-tagged palladium catalyst

A general method for polymer-assisted solution-phase (PASP) Suzuki reactions employing a combination of anthracene-tagged palladium catalyst and anthracene-tagged boronic acid with a polymer-supported carbonate base is reported. The anthracene-tagged catalyst allows for the easy removal of the Pd catalyst along with the dissociated phosphine ligand and phosphine oxide byproducts by sequestration through a chemoselective Diels-Alder reaction with a maleimide resin. The polymer-supported carbonate base facilitates the removal of excess boronic acid and the borane-containing byproducts present at the end of the coupling reaction. The Suzuki coupling reaction can be efficiently conducted by using combinations of the anthracene-tagged Pd catalyst, polymer-supported carbonate base, and anthracene-tagged boronic acid to yield the desired product in high purity and yield without the use of chromatography.     

Polymer-supported N-heterocyclic carbene-palladium complex for heterogeneous Suzuki cross-coupling reaction

Poly(1-methylimidazoliummethyl styrene)-surface grafted-poly(styrene) resin was prepared for the first time as a polymer-supported N-heterocyclic carbene (NHC) precursor for palladium complex by suspension polymerization. To prepare this polymer-supported NHC precursor, 1-methyl-3-(4-vinylbenzyl)imidazolium hexafluorophosphate, [MVBIM][PF6-], was synthesized as a monomer and copolymerized with styrene and DVB in water. This polymer-supported NHC precursor with imidazolium as a ligand, which exists solely on the surface of the resin, was well characterized by FE-SEM, CLSM, and IR spectroscopy. The precursor containing imidazolium readily formed a stable complex with Pd(OAc)2, and this polymer-supported N-heterocyclic carbene-palladium complex exhibited excellent catalytic activity for Suzuki cross-coupling reaction in an aqueous medium. The catalyst was recovered quantitatively from the reaction mixture by simple filtration and was able to be reused for a number of recycles with consistent activity in all of the coupling reactions.     

聚合物负载的手性催化剂和手性试剂和合成及应用

近年来,用聚合物负载的手性催化剂和手性试剂完成的不对称合成反应主要集中在潜手性酮的不对称还原反应;烯烃的不对称双羟基化反应;烯烃的不对称环氧化反应;不对称Ｄｉｅｌｓ－Ａｌｄｅｒ反应和饱和碳原子上的不对称取代反应。就近十年来聚合物负载手性催化剂和手性试剂的合成及应用进行了讨论。     

聚合物负载金鸡纳碱类手性相转移催化剂制备手性α-氨基酸研究进展

近年来,基于聚合物载体易分离、可重用等优点,聚合物负载催化剂得到了迅速的发展。本文就聚合物负载金鸡纳碱类催化剂在制备手性α-氨基酸上的应用进行了讨论,并对本领域未来的发展作一展望。     

醚功能化的膦配体的合成、负载及其在钯催化的Suzuki-Miyaura反应中的应用

合成了一种新的醚功能化的二茂铁膦3,连到Merrifield树脂上形成负载型的膦配体4;分别开展了膦配体3及其负载型的4在钯催化的Suzuki-Miyaura偶联反应中催化研究;发现相应形成的均相和多相钯催化剂可高产率地催化一系列的溴代芳烃与芳基硼酸偶联形成相应的联芳烃,以及负载型催化剂在不补加钯时具有一定的循环性能.     

Polymer-supported triphenylphosphine ditriflate: a novel dehydrating reagent

A new type of polymeric dehydrating reagent, readily prepared by the treatment of polymer-supported triphenylphosphine oxide with triflic anhydride, was found to be effective in a variety of dehydration reactions such as ester and amide formation; the polymer-supported triphenylphosphine oxide was easily recovered and reused several times without the loss of activity.     

可溶性高分子负载催化剂*

均相催化剂的负载化是解决催化剂分离与回收的一条有效途径,也是绿色化学研究的重要内容。可溶性高分子,尤其是树状大分子作为另一类催化剂载体近年来受到了越来越多的关注。通过选择合适的反应介质,可溶性高分子负载催化剂可以在均相条件下催化有机反应,反应结束后通过外加不良溶剂的固/液相分离、温度等调控的液/液相分离以及膜过滤等方法进行催化剂的分离与回收。本文概述了在可溶性高分子负载催化剂研究中取得的新进展,重点介绍了负载手性催化剂在不对称催化反应中的应用。     

Preparation of polymer-supported palladium/N-heterocyclic carbene complex for Suzuki cross-coupling reactions

A novel polymer-supported N-heterocyclic carbene (NHC) was prepared from chloromethyl polystyrene (CM PS) resin using a simple procedure, and was used as the ligand for palladium (Pd) catalysts. The polymer-supported Pd-NHC complexes efficiently catalyzed the Suzuki cross-coupling of aryl halides and phenylboronic acid in good yields and excellent purities under aqueous conditions.     

Efficient preparation of proline N-carboxyanhydride using polymer-supported bases

[Structure: see text] A procedure for the preparation of proline N-carboxyanhydride in high yield and purity is described using polymer-supported tertiary amines. The polymer-supported amine can be recycled with a basic wash and filtration of the resin. The procedure facilitates the access to the efficient preparation of the polyproline polymer with potential therapeutic interest.     

The application of non-cross-linked polystyrene-supported triphenylarsine in Stille coupling reactions

NCPS-AsPh₃ is a soluble polymer-supported triphenylarsine that performed equally well compared to free triphenylarsine as ligands in the Stille cross-coupling reaction of organic electrophiles and organostannanes, with the advantage that it can be conveniently and efficiently separated from the reaction by precipitation, and recycled for further use. The performance of this non-cross-linked polystyrene-supported arsine was found to be generally superior in Stille coupling reactions over the analogous polymer-supported phosphine, paralleling observations on the free ligands. Palladium-catalyzed modification of the polymer-supported arsine was possible through Pd-Ar/As-Ph exchange. Exploiting the ease of isolation of the polymer-supported reagent, the modified arsine is recycled for reuse in the Stille reaction and has led to a reduction in the yield of undesired scrambling products.