Iron‐Catalyzed Cross‐Coupling of 1‐Alkynylcyclopropyl Tosylates and Related Substrates

1‐Alkynylcyclopropyl tosylates react with alkylmagnesium halides in the presence of catalytic ferric acetylacetonate [Fe(acac)₃] under net propargylic substitution; allene formation, which is the prevalent reactivity mode of propargylic substrates otherwise, was noticed as a side reaction only when branched alkyl‐ or aryl‐Grignard reagents were used. These transformations represent the first successful iron‐catalyzed cross‐coupling reactions of tert‐alkyl electrophiles.

     

介孔酚醛树脂的制备及其在Suzuki反应中的应用

通过高温水热合成法制备了具有规则面心立方孔道结构的介孔酚醛树脂(命名为OMR),并以此介孔酚醛树脂为PdCl_2的载体,制备了非均相催化剂OMR@PdCl_2。催化剂OMR@PdCl_2在Suzuki反应显示了很好的催化性能并能重复使用5次而不降低催化活性。     

Iron‐Catalyzed Synthesis of Allenes from 2‐Alken‐4‐ynoates and Grignard Reagents

Treatment of 2‐alken‐4‐ynoates with methyl‐ or aryl‐Grignard reagents and iron(II) chloride (10 mol%) afforded 5‐methyl‐ or 5‐aryl‐3,4‐alkadienoates in good yields as a single isomer after aqueous work‐up. Likewise, (2‐alken‐4‐ynoyl)oxazolidinones afforded (5‐methyl‐3,4‐alkadienoyl)oxazolidinones. The aldol‐type reaction with acetone was also possible in place of the hydrolytic work‐up.     

Grignard Reagents and Non‐Precious Metals: Cheap and Eco‐Friendly Reagents for Developing Industrial Cross‐Couplings. A Personal Account

Grignard reagents are probably the best organometallics to develop large‐scale eco‐friendly cross‐couplings compatible with the requirements of sustainable development. This account aims to highlight some reactions having an interesting industrial potential and gives the personal point of view of the authors on some attractive fields of research in this area.

     

Cobalt‐Catalyzed Cross‐Coupling Reaction between Functionalized Primary and Secondary Alkyl Halides and Aliphatic Grignard Reagents

The coupling of primary and secondary unactivated alkyl bromides with alkyl‐Grignard reagents was performed in good yields under mild conditions by using a new catalytic system: consisting of cobalt chloride and tetramethylethylenediamine (CoCl₂⋅2 LiI, 4 TMEDA). The reaction is very chemoselective since ketone, ester and nitrile functions are tolerated.     

2,2′-Bipyridine chelates substituted with alkyne groups,and their Ru(II) complexes

The palladium-catalyzed cross-coupling of 5-bromo-2,2′-bipyridine and 5,5′-dibromo-2,2′-bipyridine with phenylacetylene leads to 2 and 3 , and the reaction of 5-ethinyl-2,2′-ethinyl-2,2′-bipyridine with 1,4-diiodo-2,5-dibutyloxybenzene provides 4 . Ruthenium complexes were prepared by reaction of the ligands 2 – 4 with [Ru(bpy)₂Cl₂].The ligands 2 and 4 show a fluorescence quantum yield near 100%. Further photophysical properties of the ligands and their ruthenium complexes were given     

Synthesis of 2,4‐ and 2,5‐Disubstituted Oxazoles via Metal‐ Catalyzed Cross‐Coupling Reactions

The rapid synthesis of 2,4‐ and 2,5‐disubstituted oxazoles via metal‐catalyzed cross‐coupling reactions is reported. The 4‐ or 5‐position of the corresponding 4‐ or 5‐halogenated 2‐butylthiooxazoles was successfully functionalized via Suzuki–Miyaura, Sonogashira and Stille cross‐coupling reactions. The 2‐position of the 2‐butylthiooxazoles obtained was further coupled to various organozinc reagents through palladium‐ or nickel‐mediated cross‐coupling reactions.     

Improved Stability and Catalytic Activity of Palladium Nanoparticle Catalysts using Phosphine‐Functionalized Imidazolium Ionic Liquids

Palladium nanoparticles (Pd NPs) stabilized by 6 different phosphine‐functionalized ionic liquids (PFILs) were synthesized in imidazolium‐based ionic liquids (ILs) using H_2(g) (4 bar) as a reductant. Characterization showed well‐dispersed particles of ∼3 nm (TEM) and confirmed the PFIL stabilization of the NPs (XPS). The PFILs were composed of an imidazolium functionality separated from the phosphine group by a propyl or undecyl chain. The counter anions for both FILs and IL solvents were chosen from N‐bis(trifluoromethanesulfonyl)imide (Tf₂N⁻), trifluoromethanesulfonate (TfO⁻) or hexafluorophosphate (PF₆⁻). Colloidal suspensions of the Pd NPs were employed as biphasic hydrogenation catalysts for the reduction of the olefinic bond in styrene under mild conditions (50 °C, 4 bar H_2(g), 1.5 h). The PFIL‐stabilized Pd NPs were effective hydrogenation catalysts and showed superior activity and recyclability over NPs synthesized in the absence of PFILs. Poisoning tests of the Pd NP catalysts and characterization of the electronic properties of the phosphine were also performed.     

Iron‐Catalyzed Regio‐ and Stereoselective Conjugate Addition of Aryl‐Grignard Reagents to α,β,γ,δ‐Unsaturated Sulfones and its Synthetic Application

The iron‐catalyzed δ‐addition of aryl‐Grignard reagents to α,β,γ,δ‐unsaturated sulfones proceeded in a regio‐ and stereoselective manner to give cis‐4‐aryl‐2‐alkenyl sulfones. Allylic alkylation of the resultant products was performed without isomerization of the cis‐olefin to give cis‐4‐aryl‐1,1‐dialkyl‐2‐alkenyl sulfones, which upon intramolecular Friedel–Crafts reaction with aluminum chloride gave 1,4‐dihydronaphthalenes having a quaternary carbon center.     

功能化层状硅酸镍在磁、电及催化领域的应用

二维纳米材料层状硅酸镍（Ni-PS）具有片层结构规则有序、比表面积高和层间性能可调等优点,作为功能材料在磁、电及催化等领域具有广泛的应用前景。本文在综述了Ni-PS的合成机理和制备方法的基础上,介绍了引入有机Si源、利用金属离子（或氧化物）进行掺杂、合成纳米管以及与碳基材料进行复合等手段来调控Ni-PS的结构和性能,详细阐述了Ni-PS或作为前体在制备高质量金属纳米粒子、电极材料、磁性载体和重金属离子吸附剂等方面的应用,着重指出Ni-PS的独特层状结构能够在还原过程中限制金属扩散和保护纳米粒子不被氧化和烧结长大,可用于制备新型高效Ni基催化剂,被广泛应用于制合成气、催化制氢/加氢及分子链催化重构等。最后,提出了Ni-PS在材料领域的发展方向和建议：深入研究Ni-PS的合成技术和改性方法,制备高性能、多功能Ni-PS及复合材料,进一步拓展其在功能材料和工程材料领域的应用。     

Synthesis and characterization of tridentate phenoxy‐imine ligand [N,N,O] nickel(II) and palladium(II) complexes and their catalytic behaviors in vinyl polymerization of norbornene

In this study, new complexes LNiCl( 1 ), LNiBr( 2 ), LNiI( 3 ), and LPdCl( 4 ) (L = 4,6‐di‐tert‐butyl‐2‐(N‐(quinolin‐8‐yl)iminomethyl)phenolato) have been synthesized and characterized. X‐ray diffraction studies on Complexes 1 and 4 revealed that N, N, O, and halogen atoms coordinated to metal, with a nearly square planar geometries in all cases. All these complexes are robust and exhibit high activities for the addition polymerization of norbornene (NB) with methylaluminoxane as cocatalyst [up to 47.62 kg PNB(mmol of Ni)^?1h^?1] and also lead to various activities and molecular weights of polynorbornenes under different reaction conditions. It is noteworthy that Complexes 1 and 4 show better activity under higher reaction temperature of 80°C. However, Complex 2 showed lower activity, and Complex 3 was found nearly inert toward NB polymerization, probably, because of thermal instability. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Flow-Based,Cerium Oxide Enhanced,Low-Level Palladium Sonogashira and Heck Coupling Reactions by Perovskite Catalysts

A flow chemistry procedure for Sonogashira and Heck cross-coupling reactions using a low-level palladium perovskite catalyst (LaFe_0.95Pd_0.05O₃) deposited on cerium oxide is reported. The catalyst was generated in situ at high temperature using a flow platform. The system could be applied to a wide range of functionalised substrates, allowing clean and fast delivery of the products within a few minutes (10–30 min), after scavenging with thiourea polymer (QP-TU) and sulfonic acid resin (QP-SA). The use of an in-line evaporator/solvent switching device allowed us to recover the solvent and transport the material into the following stage. The catalyst could be continuously used for at least 24 h, without any noticeable decrease in the catalytic efficiency. In one example the system was scaled to deliver 10 mmol of product.     

Copper‐Catalysed Conjugate Addition of Grignard Reagents to 2‐Methylcyclopentenone and Sequential Enolate Alkylation

The copper/Rev‐JosiPhos‐catalysed asymmetric conjugate addition of Grignard reagents to 2‐methylcyclopentenone ( 1 ) provides 2,3‐disubstituted cyclopentanones in high yields and enantioselectivities, and good diastereoselectivities. Reaction of the in situ formed enolate with various alkylating reagents in the presence of 1,3‐dimethyltetrahydropyrimidine‐2(1H)‐one (DMPU) affords the corresponding products in a one‐pot reaction. This procedure creates two vicinal stereocentres, one of them quaternary.

     

Palladium Decorated,Amine Functionalized Ni-, Cd- and Co-Ferrite Nanospheres as Novel and Effective Catalysts for 2,4-Dinitrotoluene Hydrogenation

2,4-diaminotoluene (TDA) is one of the most important polyurethane precursors produced in large quantities by the hydrogenation of 2,4-dinitrotoluene using catalysts. Any improvement during the catalysis reaction is therefore of significant importance. Separation of the catalysts by filtration is cumbersome and causes catalyst loss. To solve this problem, we have developed magnetizable, amine functionalized ferrite supported palladium catalysts. Cobalt ferrite (CoFe₂O₄-NH₂), nickel ferrite (NiFe₂O₄-NH₂), and cadmium ferrite (CdFe₂O₄-NH₂) magnetic catalyst supports were produced by a simple coprecipitation/sonochemical method. The nanospheres formed contain only magnetic (spinel) phases and show catalytic activity even without noble metals (palladium, platinum, rhodium, etc.) during the hydrogenation of 2,4-dinitrotoluene, 63% (n/n) conversion is also possible. By decorating the supports with palladium, almost 100% TDA selectivity and yield were ensured by using Pd/CoFe₂O₄-NH₂ and Pd/NiFe₂O₄-NH₂ catalysts. These catalysts possess highly favorable properties for industrial applications, such as easy separation from the reaction medium without loss by means of a magnetic field, enhanced reusability, and good dispersibility in aqueous medium. Contrary to non-functionalized supports, no significant leaching of precious metals could be detected even after four cycles.     

Regio‐ and Stereoselective Preparation of β,γ‐Unsaturated Carboxylic Acids by One‐Pot Sequential Double 1,6‐Addition of Grignard Reagents to Methyl Coumalate

An efficient regio‐ and stereoselective metal‐catalyzed addition of two Grignard reagents (homo‐coupling, 2 RMgX or hetero‐coupling, R¹MgX+R²MgX) to methyl coumalate (methyl 2‐oxo‐2H‐pyran‐5‐carboxylate) is described. This synthetic approach opens the access to a wide variety of functionalized β,γ‐unsaturated carboxylic acids in a modular way. Control of the chemo‐ and stereoselectivity of this one‐pot procedure is discussed.

     

Novel Palladium‐on‐Carbon/Diphenyl Sulfide Complex for Chemoselective Hydrogenation: Preparation,Characterization, and Application

A diphenyl sulfide immobilized on palladium‐on‐carbon system, Pd/C[Ph₂S], was developed to achieve the highly chemoselective hydrogenation of alkenes, acetylenes, azides, and nitro groups in the presence of aromatic ketones, halides, benzyl esters, and N‐Cbz protective groups. Instrumental analyses of the heterogeneous catalyst demonstrated that diphenyl sulfide was embedded on Pd/C via coordination of its sulfur atom to palladium metal or physical interaction with graphite layers of the activated carbon. The catalyst could be recovered and reused at least five times without any significant loss of the reactivity.     

Palladium on Carbon‐Catalyzed One‐Pot N‐Arylindole Synthesis: Intramolecular Aromatic Amination,Aromatization, and Intermolecular Aromatic Amination

Indole and indoline derivatives were selectively and temperature dependently synthesized via the intramolecular cross‐coupling reaction between the amino and aromatic bromine functionalities of 2‐bromophenethylamine derivatives in the presence of 10% palladium on carbon (Pd/C), 1,1′‐bis(diphenylphosphino)ferrocene (DPPF), and sodium tert‐butoxide (NaO‐t‐Bu) in mesitylene at 140 and 200 °C, respectively. The neutralization using acetic acid after formation of the indoline derivatives effectively promoted their aromatization, and the corresponding indole derivatives were obtained at 140 °C. Furthermore, various aryl groups were also introduced to the N‐1 position of the indole, pyrrole, and carbazole rings by their direct intramolecular arylation with aryl halides and a one‐pot protocol for N‐arylindole synthesis from 2‐bromophenethylamine was developed.

     

镍、钴、钯镀层的防铜渗性能比较

以镍、钴、钯镀层作为铜基体镀金的防渗铜中间层可以有效地防止铜原子扩散到金属表面。采用ＳＥＭ、ＥＤＡＸ、ＸＲＤ等方法研究铜在中金属内的扩散机理和扩散系数,探讨了扩散过程与这３种金属晶体结构、晶粒大小以及Ｘ－射线衍射特性的关系。     

Fine Chemical Synthesis with Homogeneous Palladium Catalysts: Examples,Status and Trends

During the last decade several palladium-catalyzed reactions have been developed and optimized to a stage that enables application on an industrial scale. The importance of these reactions as novel key steps for fine chemical synthesis is shown. Examples include palladium-catalyzed Heck, Suzuki and Sonogashira coupling reactions, telomerization of 1,3-butadiene with nucleophiles, and carbonylation of aromatic and benzylic halides.     

Iron Dihydride Complexes: Synthesis,Reactivity, and Catalytic Applications

Iron dihydride complexes often play important roles in catalytic reactions that employ reducing agents such as H₂, boranes, and silanes. Development of more efficient and selective iron-based catalysts for these processes requires effective synthetic strategies and a deeper understanding of the reactivity of the dihydride complexes. The purpose of this review is to provide the readers with an overview of different ligand systems that have been used to support iron dihydride complexes.