锌卟啉修饰的双核钌卡宾烯烃复分解催化剂的合成及催化性能检测

为了得到稳定性更好、活性更高的烯烃复分解催化剂,本文采用有机合成的方法,以钌卡宾烯烃复分解催化剂为主体,用锌卟啉进行修饰,得到锌卟啉修饰的Grubbs-Hoveyda型双核钌卡宾烯烃复分解反应催化剂,产物结构使用核磁共振方法进行表征。 用0.1%化学计量催化剂催化几种代表性底物闭环复分解(RCM)反应产率能达到95%,对于特定的交叉烯烃复分解反应(CM),延长反应时间也能得到93%的较高产率。 研究结果为Grubbs-Hoveyda催化剂的修饰提供了新方法和理论依据。     

非均相催化烯烃交叉复分解反应

烯烃交叉复分解反应作为石油化工领域一种重要过程,为各种单烯烃间的互相转化提供了一条有效的途径。特别是在利用正丁烯生产丙烯和其它重要单烯烃方面,复分解反应受到越来越多的重视。本文对烯烃交叉复分解反应(CM)的进展进行了综述,讨论了CM各种工艺的技术特点及反应机理,重点介绍了WO₃/SiO₂、Re₂O₇/Al₂O₃、MoO₃/Al₂O₃3类催化剂的最新改进及相应的理论分析,试图理清催化剂今后发展的思路,为进一步改进催化剂的性能提供相关的依据。     

环(烷基)(氨基)卡宾及其在烯烃复分解反应中的研究展望

烯烃复分解反应是形成碳碳双键的重要反应之一,其发展与结构明确的钌催化剂[L2X2Ru=CHR]中配体的创制密切相关.1999年,环二氨基卡宾配体的引入极大提高了催化剂的活性、稳定性以及官能团适用性.2005年,Bertrand等发展了一种比环二氨基卡宾具有更强给电子能力的配体──环(烷基)(氨基)卡宾(CAACs)配体,且卡宾中心α位为一季碳原子,这使得其空间环境与其他类型卡宾配体有很大差异.首先概述了CAACs配体的合成及性质,紧接着讨论了其在烯烃复分解催化反应中的研究进展,最后对该领域所存在的问题进行简要分析并对其发展作了展望.     

Grubbs催化剂合成研究进展

烯烃复分解反应通过催化使两个烯烃碳碳双键断裂,再重新组合形成新的碳碳双键,是以烯烃作为底物构建碳碳双键的重要方法.从反应类型来分,烯烃复分解反应主要有：关环复分解反应（RCM）,开环复分解聚合反应（ROMP）,交叉复分解反应（CM）及非环二烯复分解反应（ADMET）.在天然产物的全合成,药物化学和材料科学中均有广     

取代8-羟基喹啉钌络合物催化Friedl?nder反应合成喹啉衍生物

Friedl?nder喹啉合成法是以邻胺基芳基醛或酮与有α-亚甲基的酮环化制备喹啉的反应,报道了一种喹啉钌络合物催化Friedl?nder法合成喹啉的方法.首先,以8-羟基喹啉钌络合物为催化剂,对模板反应邻氨基苯甲醇和苯乙酮合成2-苯基喹啉进行了反应条件优化实验.重点对比研究了8-羟基喹啉钌络合物配体上不同取代基对反应收率的影响,其中5-甲基-8-羟基喹啉(1e)钌络合物催化邻氨基苯甲醇和苯乙酮合成2-苯基喹啉获得了73%的最高收率.结合IR, UV以及密度泛函理论(DFT)计算讨论了配体结构与催化性能之间的关系.提出了β-H消除形成醛过渡态,交叉aldol反应再亚胺环化,最后脱水生成目标产物的可行机理.以(1e)₃Ru为催化剂,在优化的反应条件下进行了底物扩展研究,以69%～94%的收率合成了32个不同取代的喹啉衍生物,验证了方法的普适性.     

水/有机两相体系中钌膦配合物催化苯乙酮及其衍生物的不对称加氢反应

 将手性二胺(1S,2S)-1,2-二苯基乙二胺二磺酸钠((1S,2S)-DPENDS)修饰的钌膦配合物用于催化水/有机两相体系中苯乙酮的不对称加氢. 结果表明, (1S,2S)-DPENDS和KOH的浓度对反应有很大影响,二者的协同作用使配合物的催化活性和产物的对映选择性大大提高. 对温度、压力、底物/钌的摩尔比和膦配体/钌摩尔比等反应条件进行优化后,以［RuCl2-(TPPTS)2］2为催化剂前体催化苯乙酮不对称加氢时,产物的ee值可达66.4%, 催化剂经过简单的相分离即可循环使用.     

梳形接枝共聚物的合成(Ⅱ)——载体化钌卡宾络合物催化降冰片烯基聚苯乙烯的开环岐化聚合

由石油化工副产C₅馏份提取双环戊二烯(DCPD)、以聚合物负载三氟化硼为催化剂进行DCPD与烯丙基氯(AC)的Diels-Alder反应合成5-氯甲基-2-降冰片烯(NBCH₂Cl),经锂代反应后用以引发苯乙烯的活性阴离子聚合合成了降冰片烯(NB)基聚苯乙烯(PS)大分子环烯单体NB-PS,在聚合物负载钌卡宾络合物[RuCl₂(PPh₃)₂(=C=CHtBu)]催化(引发)作用下进行大分子单体NB-PS的开环歧化聚合(ROMP)合成了梳形接枝共聚物PNB-g-PS.实验结果表明所合成聚合物负载硼、钌络合物催化剂的性能均明显优于对应非负载体.讨论了上述催化剂的聚合物载体效应的机理及温度、溶剂等对活性阴离子聚合反应的影响.     

一锅法合成芳(杂环)胺亚甲基双膦酸四乙酯

以I₂为催化剂,原甲酸三乙酯、芳(杂环)胺和亚磷酸二乙酯为原料,室温无溶剂条件下,一锅合成了系列芳(杂环)胺亚甲基双膦酸四乙酯,收率96%~99%。 当I₂物质的量分数为5%时,产物收率最高。 本方法底物适用范围广,操作简单。 I₂作为催化剂,安全高效。     

水溶性钌-氢配合物催化1-已烯双键异构化反应研究

研究了水溶性钌-氢配合物RuHCl(TPPTS)3在水/有机两相体系中催化1-己烯双键异构化反应.考察了反应温度、时间、膦配体浓度、相转移催化剂CTAB浓度以及底物与催化剂摩尔比等对转化率和产物选择性的影响.在最佳条件下1-己烯转化率达到82.4%,2-己烯选择性21.2%,3-己烯61.2%,没有发现骨架异构化.催化剂可重复使用5次.     

盐酸西那卡塞中间体的制备新方法研究

本文首次利用烯烃交叉复分解反应,在卡宾钌催化剂条件下,以高达93%的收率,制得西那卡塞关键中间体5,再经氢化还原、脱保护基、成盐制得盐酸西那卡塞。该工艺反应条件温和,操作简便,安全性高。     

Synthesis of six-membered cyclic siloxanes via enyne metathesis with a ruthenium catalyst generated in situ

The catalytic system in situ generated by combination of [RuCl₂(p-cymene)]₂ as a ruthenium source, 1,3-bis(mesityl)imidazolinium chloride (MesH₂ImCl) as a bulky electron-releasing carbene precursor and cesium carbonate as a base, is shown to be an efficient catalyst for the metathesis reaction of propargylic allylsilyl ethers R¹---CCCR₂---O---SiMe₂---CH₂CH=CH₂. The metathesis products, the cyclic siloxanes, were obtained after complete conversion of the enynes in 67–87% isolated yields. These six-membered ring compounds contain the 1,3-diene unit that is used in Diels–Alder reaction and give access to heterobicyclic derivatives. The resulting cyclic siloxanes are selectively opened under oxidative conditions with H₂O₂ to afford allylic diols, with fluoride to form conjugated triene and under hydrogenation conditions with Pd/C catalyst to give a tetrasubstituted alkene.     

Easily accessible and robust olefin-metathesis catalysts based on ruthenium vinylidene complexes

Nine mixed ligand ruthenium(II) vinylidene complexes with the general formula: [RuCl₂{=C=CHR′}(PCy₃)(L)] and [RuCl{=C=CHR′}(PCy₃)(sal-R)] (L=N-heterocyclic carbene, sal-R=salicylaldiminate anion, R′=Ph, SiMe₃, ^tBut) has been synthesized and characterized. These complexes are easily accessible from [RuCl₂(p-cymene)]₂, terminal alkynes, imidazolium salts or salicylaldimine salts and they have been found to serve as good catalyst precursors for ring-opening metathesis polymerization (ROMP) of norbornene, substituted norbornenes, polycyclic alkenes and cyclooctene and ring-closing metathesis (RCM) of ,ω-dienes. Furthermore, these precursors possess extremely high stability toward air, heat and moisture in comparison with other metathesis-active alkylidene ruthenium systems. No significant catalyst decomposition was found for several days at elevated temperatures.     

关环复分解反应(RCM)及其催化剂研究进展

综述了近年来关环复分解 (RCM )反应及其催化剂的研究进展 ,对RCM反应发展以来被广泛应用的催化剂 ,如Schrock催化剂和Grubbs催化剂等进行了归纳和总结 ,讨论了RCM反应在全合成中的应用     

Homobimetallic Ruthenium-Ethylene,Vinylidene, Allenylidene,and Indenylidene Catalysts for Olefin Metathesis

Summary: Following the discovery of bimetallic ruthenium scaffold ( 1 ), two new homobimetallic ruthenium-N-heterocyclic carbene complexes ( 2 , 3 ) were synthesized and found highly suitable for promoting ROMP, RCM, and CM reactions. Results from this study indicated that the ethylene ligand was highly labile and that adding a small amount of a terminal alkyne to the reaction media had a beneficial influence on the metathetical activity. These observations prompted us to further investigate the role of the alkyne co-catalyst. Thus, homobimetallic ruthenium-arene complexes bearing vinylidene ( 4 , 5 ), allenylidene ( 6 ), and indenylidene ( 7 ) ligands were prepared from complex 1 and propargyl alcohol derivatives. Their catalytic activities were probed in several types of olefin metathesis reactions, and they were found valuable intermediates for the safe and efficient one-pot synthesis of the Hoveya–Grubbs isopropoxybenzylidene catalyst ( 8 ).     

A Fast‐Initiating Ionically Tagged Ruthenium Complex: A Robust Supported Pre‐catalyst for Batch‐Process and Continuous‐Flow Olefin Metathesis

In this study, a new pyridinium‐tagged Ru complex was designed and anchored onto sulfonated silica, thereby forming a robust and highly active supported olefin‐metathesis pre‐catalyst for applications under batch and continuous‐flow conditions. The involvement of an oxazine–benzylidene ligand allowed the reactivity of the formed Ru pre‐catalyst to be efficiently controlled through both steric and electronic activation. The oxazine scaffold facilitated the introduction of the pyridinium tag, thereby affording the corresponding cationic pre‐catalyst in good yield. Excellent activities in ring‐closing (RCM), cross (CM), and enyne metathesis were observed with only 0.5 mol % loading of the pre‐catalyst. When this powerful pre‐catalyst was immobilized onto a silica‐based cationic‐exchange resin, a versatile catalytically active material for batch reactions was generated that also served as fixed‐bed material for flow reactors. This system could be reused at 1 mol % loading to afford metathesis products in high purity with very low ruthenium contamination under batch conditions (below 5 ppm). Scavenging procedures for both batch and flow processes were conducted, which led to a lowering of the ruthenium content to as little as one tenth of the original values.     

Application of a Grubbs–Hoveyda Metathesis Catalyst Noncovalently Immobilized by Fluorous–Fluorous Interactions

A Grubbs–Hoveyda metathesis catalyst bearing a tris(perfluoroalkyl)silyl tag for efficient noncovalent attachment to fluorous silica gel (FSG) was synthesized and employed in ring‐closing metathesis (RCM) reactions in CH₂Cl₂. After the reaction, a solvent switch to a polar system allowed for recovery of the catalyst by filtration and its reuse. The approach was demonstrated for a number of different substrates. Furthermore, it was shown that the application of this catalytic system yielded products with low ruthenium content.     

Ring-Closing Metathesis of Ene-Ynamide: Application to the Synthesis of Medium-Sized Cyclic Dienamide

Summary: Ring-closing metathesis (RCM) of ene-ynamide, which could be applied to the synthesis of various heterocycles containing 7- and 8-membered rings, was investigated. Ene-ynamides are easily synthesized by the known method. When a toluene solution of ene-ynamide was stirred in the presence of a catalytic amount of second-generation ruthenium carbene complex 1 under an ethylene atmosphere, RCM proceeded smoothly to provide a heterocyclic compound having a diene moiety in good to high yield. A substituent of the ynamide moiety affected the yield of the cyclized product.     

Synthesis and reactivity of homogeneous and heterogeneous ruthenium-based metathesis catalysts containing electron-withdrawing ligands

The synthesis and heterogenization of new Grubbs-Hoveyda type metathesis catalysts by chlorine exchange is described. Substitution of one or two chlorine ligands with trifluoroacetate and trifluoromethanesulfonate was accomplished by reaction of [RuCl(2)([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (IMesH(2) = 1,3-bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene) with the silver salts CF(3)COOAg and CF(3)SO(3)Ag, respectively. The resulting compounds, [Ru(CF(3)SO(3))(2)([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (1), [RuCl(CF(3)SO(3))([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (2), and [Ru(CF(3)CO(2))(2)([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (3) were found to be highly active catalysts for ring-closing metathesis (RCM) at elevated temperature (45 degrees C), exceeding known ruthenium-based catalysts in catalytic activity. Turn-over numbers (TONs) up to 1800 were achieved in RCM. Excellent yields were also achieved in enyne metathesis and ring-opening cross metathesis using norborn-5-ene and 7-oxanorborn-5-ene-derivatives. Even more important, 3 was found to be highly active in RCM at room temperature (20 degrees C), allowing TONs up to 1400. Heterogeneous catalysts were synthesized by immobilizing [RuCl(2)([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] on a perfluoroglutaric acid derivatized polystyrene-divinylbenzene (PS-DVB) support (silver form). The resulting supported catalyst [RuCl(polymer-CH(2)-O- CO-CF(2)-CF(2)-CF(2)-COO)([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (5) showed significantly reduced activities in RCM (TONs = 380) compared with the heterogeneous analogue of 3. The immobilized catalyst, [Ru(polymer-CH(2)-O-CO-CF(2)-CF(2)-CF(2)-COO)(CF(3)CO(2))([double bond]CH-o-iPr-O-C(6)H(4))(IMesH(2))] (4) was obtained by substitution of both Cl ligands of the parent Grubbs-Hoveyda catalyst by addition of CF(3)COOAg to 5. Compound 4 can be prepared in high loadings (160 mg catalyst g(-1) PS-DVB) and possesses excellent activity in RCM with TONs up to 1100 in stirred-batch RCM experiments. Leaching of ruthenium into the reaction mixture was unprecedentedly low, resulting in a ruthenium content <70 ppb (ng g(-1)) in the final RCM-derived products.