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.     

利用Heck反应合成咖啡酸苯乙酯

以4-溴儿茶酚和丙烯酸苯乙酯为原料,经过邻二酚羟基的保护、Heck偶联和脱保护3步反应合成了咖啡酸苯乙酯.其中,以乙酰基保护的4-溴儿茶酚在优化的Heck反应条件下,可获得40%收率的咖啡酸苯乙酯.确定的最佳Heck反应条件为:混合溶剂甲苯/二甲基甲酰胺的体积比为4∶1,醋酸钯(0.05 mmol),三苯基膦(0.15 mmol),三乙胺(2 mmol),反应温度90℃,反应时间24 h.该方法具有通用性好、原料易得和操作相对简单的优点.     

钯催化Heck反应制备长共轭生色二苯乙烯衍生物

采用Heck反应合成出6个带有不同推拉电子基团的二苯乙烯衍生物,产率68%～84%.研究了反应物分子结构对Heck偶联反应的影响,对实验条件进行了优化并探讨了其反应机理.结果表明,反应温度120℃,溶剂DMF 和Et3N体积比为2: 1时可以获得较高产率.同时我们还发现,不同的反应物结构对Heck反应产率的影响较大,随着反应物中双键的电子云密度的降低(对甲基苯乙烯>苯乙烯>4-乙烯吡啶),反应产率依次降低;芳卤的反应活性表现为:NO2-Ar-Br>H-Ar-Br>CH3-Ar-Br.     

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     

不对称Heck反应在天然产物合成中的应用

综述了不对称Ｈｅｃｋ反应在天然产物合成中的应用，按照分子内和分子间的不对称Ｈｅｃｋ反应分两个方面加以介绍和总结。参考文献２６篇。     

Synthesis of Entacapone by Pd-Catalyzed Heck Coupling Reaction

Synthesis of entacapone from 4-iodo-2-methoxy-phenol with 2-cyano-N,N-diethylacrylamide by palladium-catalyzed Heck reaction, as a key step, is described.     

Design and Synthesis of Bis-thioureas Ligands for Pd-Catalyzed Heck Reaction

The palladium-catalyzed arylation of olefins (the Heck reaction) is one of the most versatile tools for C-C bond formation in organic synthesis. Phosphine ligands are generally used to stabilize the reactive palladium intermediates, the air-sensitivity of phosphine ligands, however, places significant limits on their synthetic applications. Recently, Yang1 and we2 have reported Heck and Suzuki reactions of highly active arenediazonium salts and halides catalyzed by air-stable monothiourea-Pd…     

钯-氧化石墨烯-Fe3O4催化剂的制备及其对Heck反应催化研究

采用离子交换和共沉淀两步法合成了氧化石墨烯-四氧化三铁复合物（GO—Fe3O4）,并负载钯（Pd）纳米颗粒得到了催化剂Pd—GO—Fe3O4．用SEM和FTIR对其表面形貌和组成进行了表征．160℃下,以N,N-二甲基甲酰胺（DMF）为溶剂,将该催化剂用于溴苯和丙烯酸酯的Heck偶合反应中,产率可达98．6％,且连续使用4次后,产率仍可保持97．51％．     

Synthesis of Nonsymmetric Divinylarenes by a Heck/Wittig Reaction Combination

A protocol for a one-pot Heck reaction/Wittig olefination to divinylarenes has been developed.     

Heck反应合成1,2-二芳基乙烯类衍生物的新方法

以1,3-二乙烯基-1,1,3,3-四甲基二硅氧烷（DVS）为烯源与溴代芳烃通过Heck反应一步法合成了1,2-二苯乙烯（V-bisPh）及1,2-二苯并环丁烯基乙烯（V-bisBCB）。 优化了反应条件：DMF/H2O为溶剂,温度120 ℃,溴化物（R-Br）与烯源DVS的投料摩尔比为5∶1,反应48 h,1,2-二苯并环丁烯基乙烯产率为45.1%,1,2-二苯乙烯产率为48.6%。     

Palladium-Catalyzed 8-Exo Trig Intramolecular Heck Reaction Under Microwave Irradiation in the Presence of Basic Alumina

The Heck cross-coupling reaction has been employed for efficient conversion of quinolines to benzoxocinoquinoline through a microwave-assisted palladium-catalyzed intramolecular cyclization in the presence of basic alumina.     

固体碱D301树脂在杂环卤代芳烃Heck反应中的应用

利用D301树脂作为碱性试剂, 在无膦配体, 低用量Pd(OAc)2催化下进行了杂环卤代芳烃与烯烃的Heck芳基化反应研究, 实验结果表明D301树脂作为固体碱不仅可使反应获得满意的收率, 而且具有良好的重复使用性能.     

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     

Synthesis of Arylethylene or Diarylethylene Compounds by Pd-Catalyzed Heck Coupling Reaction

We have developed an effective palladium-catalyzed arylation or diarylation couplings of olefins with various aryl halides in the presence of readily available ligands. This method is simple, economical, and practical for the synthesis of arylethylene and diarylethylene.

Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for full experimental and spectral details.     

Heck反应一锅法合成3-乙氧羰基-2-甲基吲哚的研究

吲哚以其独特的化学结构使其衍生出的化合物都具有独特的生理活性,它们在医药、农药、香料、色氨酸等领域发挥着重要的作用,是一类非常重要的杂环类精细化工中间体。因此,长久以来发展简单、通用,特别是具有区域选择性的方法合成吲哚类化合物一直吸引了人们的研究兴趣[1]。在已经发展起来的合成吲哚类化合物的许多方法中,Heck反应[2],即Pd催化卤代物与烯烃构筑碳碳键的方法,由于其温和的反应条件和广泛的官能团相容性,已经成为合成吲哚及其衍生物采用最多的方法[3]。早在1984年,Suzuki[4]就报道合成了化合物3-乙氧羰基-2-甲基吲哚,其是由…     

Fe3O4-氧化石墨烯-钯催化剂的制备及其对Heck 反应催化研究

采用离子交换和共沉淀两步法合成了氧化石墨烯-四氧化三铁复合物(GO-Fe3O4),并负载钯(Pd)纳米颗粒得到了催化剂Fe3O4-GO-Pd。用SEM和FTIR对其表面形貌和组成进行了表征。160 ℃下,以N,N-二甲基甲酰胺(DMF)为溶剂,将该催化剂用于溴苯和丙烯酸酯的Heck偶合反应中,产率可达98.64 %,且连续使用4次后,产率仍可保持97.51 %。     

Regioselectivity in the Intramolecular Heck Reaction of a Series of Cyclic Sulfonamides: An Experimental and Computational Study

Regioselectivity in the intramolecular Heck reaction of a series of N‐sulfonyl‐2,5‐dihydro‐3‐substituted pyrroles was studied. These substrates are unbiased in terms of the formed ring size of the new heterocycle. Results indicate that high levels of regioselectivity are observed under a range of conditions, and that there is an underlying propensity for carbon–carbon bond formation at the most hindered end of the alkene. For two examples (3‐Me and 3‐tBu), DFT calculations were performed and indicate that in both cases, the modelled transition state for carbopalladation is energetically lower for the experimentally preferred isomer.     

交联木质素负载钯催化剂的制备及对Heck反应的催化性能研究

以天然木质素为原料, 用甲醛对其进行交联得到了交联木质素, 通过简单的方法合成了负载钯催化剂, 用XPS、 TG、 DTA等对其进行了表征. 该催化剂在空气氛围中能很好的催化乙烯基化合物与芳基碘的Heck反应. 如在较低的温度下(40 ℃)催化丙烯酸与碘苯的反应, 产率高达73.7%, 显示了较高的催化活性. 该催化剂重复使用5次, 产率仍高达90%, 显示该催化剂有良好的重复使用性能.