负载型Heck反应催化剂的研究进展

Heck反应是一类重要的C-C偶联反应,传统的均相Heck反应催化剂存在分离和回收困难等问题;近年来负载型Heck反应催化剂的研究引起了人们的广泛关注.本文综述了钯基和非钯基负载型Heck反应催化剂的研究进展,评述了不同载体上催化活性组分对Heck反应的特点,并展望了其发展趋势.     

纳米碳纤维负载钯催化剂在Heck反应中的应用——载体相互作用的影响

使用多元醇还原法制备了均匀分散的钯纳米颗粒.将钯纳米颗粒负载于板式、鱼骨式和管式纳米碳纤维,得到稳定、可重复使用的非均相催化剂.实验结果表明,钯纳米胶粒同载体之间的电位差对钯在载体上的负载量、粒子大小以及Heck反应中钯的溶失量有很大的影响.在制备过程中,增加钯纳米胶粒同纳米碳纤维表面的电位差能够大大降低钯在Heck反应中的流失.催化剂的反应活性随钯粒子的增大而降低.     

Efficient Synthesis of Pyridylacrylonitriles via the Heck Reaction

A new synthetic pathway to pyridylacrylonitriles has been developed based on a palladium‐catalyzed Heck reaction. The optimized process and the preparation of related functionalized pyridylacrylonitriles are discussed.     

padc-pd催化剂的制备及对heck反应的催化性能

padc;钯;负载型催化剂;heck反应     

木质素负载钯催化剂的制备及对Heck反应的催化性能

以天然木质素和PdC l2为原料,合成了木质素负载钯催化剂,用IR、XPS、TG、DTA等对其进行了表征.研究表明,该催化剂在空气氛围中能催化丙烯酸与芳基碘的Heck反应,并有一定的重复使用性能.     

淀粉负载钯催化剂的制备及对Heck反应的催化性能

淀粉负载钯催化剂的制备及对Heck反应的催化性能;淀粉;钯;负载型催化剂;Heck反应     

Pd/MWCNTs(多壁碳纳米管)催化剂的制备及其Heck反应催化活性

以浓硝酸处理后的多壁碳纳米管(MWCNTs)为载体,通过微波辅助法简单而快速地制备了高度分散、粒径均一的Pd/MWCNTs催化剂。利用XRD、HRTEM、XPS等手段对催化剂进行了表征。考察了Pd/MWCNTs催化剂对Heck反应的催化活性,并优化了反应温度、碱的种类和用量等反应条件。结果表明,Pd/MWCNTs在Heck反应中具有良好的催化活性。     

腐植酸负载金属配合物对Heck反应的催化性能

以腐植酸为原料,通过简单的方法制得了腐植酸负载Pd(HA-Pd)和腐植酸负载Pd/Ni催化剂(HA-Pd/Ni).用NaBH4作为还原剂,得到腐植酸负载Pd和腐植酸负载Pd/Ni催化剂的还原产物(HA-Pd(0)和HA-Pd/Ni(0)).研究了腐植酸负载Pd和腐植酸负载Pd/Ni催化剂及其还原产物对芳基卤与乙烯基化合物的Heck反应的催化性能.结果显示,该类催化剂均能够很好地催化溴苯与丙烯酸的Heck芳基化反应.     

胺基化树脂负载Pd(0)对Heck反应催化性能的研究

将氯球用胺化剂、乙二胺、胍进行胺化后负载氯化钯, 在乙醇溶液中用硼氢化钾还原, 制备了含胺功能基树脂负载钯(0)的催化剂; 研究了催化剂对含各种取代基碘代苯与丙烯酸的Heck芳基化反应催化性能. 结果表明, 该类催化剂具有良好的催化活性和重复使用性能, 其中用乙二胺功能化树脂负载的Pd(0)催化剂在90 ℃重复使用17次时能保持良好的催化活性. 催化剂反应前后的SEM形貌图和过滤液的活性试验表明催化剂活性组分Pd(0)在反应中有沥取(leaching)现象.     

钯和四齿膦配体催化剂应用于Heck反应的研究

设计合成了以联萘二胺为骨架的四齿膦配体N,N,N',N'-四(二苯基膦甲基)-(1,1'-联萘)-2,2'-二胺,并将其与钯组成的催化体系用于苯乙烯和芳卤的Heck反应,该催化体系对各种卤代芳烃都表现出了很高的催化活性.对活化底物对溴苯腈,即使底物与催化剂的物质的量比达到10 000,反应20 h几乎能达到定量转化;该催化体系对活性更低的杂环底物也取得了良好的催化效果.     

聚氯乙烯三乙撑四胺负载钯配合物的制备及对Heck反应的催化性能

以聚氯乙烯为原料, 通过胺化反应制得聚氯乙烯三乙撑四胺, 然后用较简单方法得到聚氯乙烯三乙撑四胺负载钯配合物(PVC-TETA-Pd), 利用XPS, TG, DTA和TEM等手段对其进行了表征. 热分析表明PVC-TETA-Pd在室温至250 ℃范围内有很好的热稳定性; TEM分析证实钯在PVC-TETA-Pd中分布比较均匀, 钯颗粒呈球形, 粒径在2～3 nm. PVC-TETA-Pd不需在惰性气体氛围中就能有效地催化丙烯酸、苯乙烯与芳基碘的Heck芳基化反应, 并且在较低的温度(40 ℃)或较少的催化剂用量(0.02%)下, 对Heck反应仍有较好的催化性能. PVC-TETA-Pd便于回收, 且有很好的重复使用性能, 对于碘苯与丙烯酸的反应, 重复使用十二次, 肉桂酸的产率仍达到80.1%.     

Recyclable Palladium Catalysts for the Heck/Sonogashira Reaction under Microwave‐assisted Thermomorphic Conditions

The reaction of allyl palladium(II) chloride dimer and 4,4′‐bis(R_fCH₂OCH₂)‐2,2′‐bpy, 1a–b , in the presence of AgOT_f resulted in the synthesis of cationic palladium complex, [Pd(η³‐allyl)(4,4′‐bis‐(R_fCH₂OCH₂)‐2,2′‐bpy)](OT_f), 2a–b where R_f = C₉F₁₉ ( a ), C₁₀F₂₁ ( b ), respectively. The reaction of [PdCl₂(CH₃CN)] or K₂PdCl₄ with 1b , gave rise to the synthesis of [PdCl₂(4,4′‐bis‐(C₁₀F₂₁CH₂OCH₂)‐2,2′‐bpy)], 3b . The quantitatively determined solubility curves of 2a–b and 3b in DMF indicated dramatic increase of solubility for 2a – b and 3b from ?40 to 90 °C. The catalyst‐recoverable Pd‐catalyzed Heck/Sonogashira reactions were successfully achieved in DMF with microwave‐assistance. The cationic Pd‐catalyzed Heck arylation of methyl acrylate was selected to demonstrate the feasibility of recycling 2a–b using DMF as a solvent under microwave‐assisted thermomorphic conditions. At the end of each cycle, the product mixtures were cooled, and then the catalysts were recovered by decantation. The Heck arylation catalyzed by 2b under microwave‐assisted mode exhibited good recycling results favoring the trans product. To our knowledge, this is the first example of cationic Pd‐catalyzed Heck arylation under microwave‐assisted thermomorphic conditions. Additionally, recoverable 3b ‐catalyzed Sonogashira reactions were also achieved successfully in DMF. The reactions under microwave‐assistance gave much better results in yield and in efficiency than that under conventional thermal heating.     

碳负载钯催化剂对Heck反应的催化性能

研究了钯碳催化剂对芳基卤和取代芳基卤与丙烯酸和苯乙烯的Heck芳基化反应的催化性能.结果表明:在反应温度为80℃、反应时间为8h、四丁基溴化铵(TBABr)作为溶剂和三丁胺作为碱的条件下,钯碳催化剂对不同取代芳基卤与丙烯酸和苯乙烯的Heck芳基化反应具有良好的催化性能,产物收率在80%以上.     

New binuclear Pd(II) thioamide complexes for the Heck reaction of aryl bromides

The reaction of binucleating thioamide ligands (L₁-L₃) with [PdCl₂(PPh₃)₂] in 1:2 molar ratio in methanol medium afforded a series of binuclear palladium(II) complexes. The synthesized complexes were characterized by elemental analysis and ¹H NMR. The molecular structure of one of the complexes was established by X-ray diffraction method. The binuclear palladium(II) thioamide complex has been shown to be an active catalyst for the Heck reaction of aryl bromides with alkenes.     

Heck反应最新研究进展

Heck反应是一类重要的卤代芳烃烯基化、形成新的C—C键的合成反应, 近几年来一直是催化化学和有机化学的研究热点. 总结了最近几年来国内外Heck反应新型催化体系、不对称Heck反应、Heck反应在有机合成中的最新应用等重要研究成果, 希望引起同行对Heck反应的关注.     

Heck reaction catalyzed by a recyclable palladium supported on shell powder

A novel palladium catalyst supported on shell powder has been prepared, and its application to the Heck reaction of aryl iodides with olefins has been reported. The results showed that the novel catalyst had extremely high activities for the reactions with the average yield over 90%. Also, this catalyst showed excellent stability in Heck reactions, being reused three times. The catalyst was characterized by X‐ray powder diffraction and field‐emission scanned electron microscopy images, and the energy dispersive X‐ray analyzer. Copyright © 2010 John Wiley & Sons, Ltd.     

磁性纳米颗粒负载钯催化剂对Heck反应的催化活性

采用水热法合成了碳包埋磁性纳米复合颗粒C/(Au@Fe),并以之为载体制备了纳米钯催化剂,利用透射电镜、X射线光电子能谱和振动样品磁强计等手段对催化剂进行了表征,评价了催化剂对Heck反应的催化活性.结果表明,催化剂的平均粒径约为300nm,表面覆盖着一层粒径为12nm的钯颗粒,整个催化剂呈现超顺磁性.对于碘代苯与丙烯酸之间的Heck反应,在乙酸钠或三乙胺碱性条件下反应4h,碘代苯转化率可达95%以上.催化剂重复使用10次时仍可保持很高的催化活性(碘代苯转化率88%).对于其他不同反应底物之间的Heck反应,催化剂同样显示有较高的催化活性.催化剂可稳定分散于反应体系中,并可在外磁场作用下快速与反应体系分离.     

Ultrasound-Promoted Ligand-Free Heck Reaction in Water

An ultrasound irradiation–promoted Heck reaction catalyzed by ligand-free palladium acetate was described. The ultrasound-promoted Heck reaction was carried out under mild and environmentally friendly conditions, resulting in the corresponding products with good to excellent chemical yields (up to 96% yield) and high regioselectivities and stereoselectivities (E/Z > 99:1). Acrylamide and acrylic acid were used for the first time as substrates in the ultrasound-promoted Heck reaction. It was found that the reaction could be finished within 20 min.

无配体Pd/LDH-F催化剂在Heck和Suzuki反应中的应用

 以氟离子插层的水滑石LDH-F为载体,用逐滴浸渍法制备了新型Pd/LDH-F催化剂,并用其催化溴代芳烃的Heck和Suzuki偶联反应. 用X射线衍射表征了催化剂的晶相,以等离子体发射光谱测定了溶剂中钯的流失量. 结果表明,对于Heck反应,在无配体存在和低钯用量(Pd/溴代芳烃摩尔比为0.001)的情况下, Pd/LDH-F的催化性能优于其它载体负载的Pd催化剂,显示出很高的催化活性和选择性. 在140 ℃和12 h的条件下, Pd/LDH-F催化溴苯与苯乙烯Heck反应产物的收率可达86％, 反应后催化剂经过分离,可循环使用四次其催化活性基本不变. 在DMF/水摩尔比为0.5的混合溶剂中,在室温和3 h 的条件下, Pd/LDH-F (Pd/溴代芳烃摩尔比为0.005)催化溴苯与苯基硼酸盐的Suzuki反应中,目标产物收率为99%.     

高分子负载咪唑啉钯催化剂的合成及其对Heck反应的催化性能研究

以普通商品聚丙烯腈(PAN)为原料, 合成了四种功能基化的纤维高分子载体, 挑选出其中一种与金属钯盐反应合成出了高分子负载钯催化剂. 利用元素分析、红外光谱、原子吸收光谱、SEM及XPS等手段对其结构进行了表征. 研究了该催化剂对碘代苯与丙烯酸乙酯反应的催化性能及循环使用性能.