环酮及其衍生物的光化学反应研究进展

综述了环酮及其衍生物的光化学反应的有机进展.较详细地介绍了单环酮、芳香酮、二元酮和二元环酮的光氧化反应、光还原反应、光偶联反应,尤其是对非增感光氧化反应、潜手性酮的不对称光还原反应以及激光在有机光化学反应中的应用也进行了介绍.     

Sonogashira反应研究的最新进展

对Sonogashira反应的最新研究进展作了综述. 详细地介绍了Sonogashira 反应的最新优化、联串化、绿色化以及非Pd催化的Sonogashira反应等, 同时还综述了Sonogashira反应的机理研究.     

单分散共轭齐聚物的合成方法

简要介绍了线性、星形和环状单分散共轭齐聚物的主要合成方法,并对不同方法的优缺点做了简要评述.其中,线性单分散共轭齐聚物的合成方法主要有4种,即控制聚合方法,发散合成方法,发散/收敛合成方法和指数增长合成方法.在星状单分散共轭齐聚物方面,主要介绍了两种苯环成环反应的应用.环状共轭齐聚物的合成主要介绍了聚合过程中的成环反应、线性共轭齐聚物的分子内环化反应和模板导向环化反应.     

木质素及其衍生物负载金属催化剂在有机合成中的应用研究进展

碳中和发展理念的提出使得生物质基催化剂的关注度不断提高,将木质素作为过渡金属催化剂的载体来制备非均相催化剂应用于有机合成领域,可以极大地提高木质素的利用价值.木质素结构中广泛存在的含氧官能团为金属催化剂的负载提供了多种结合位点,通过物理吸附/沉积、离子交换以及与羟基官能团通过静电络合可以有效地捕获金属粒子.首先介绍了木质素的结构,然后介绍了制备非均相催化剂的方法,重点介绍了木质素及其衍生物负载金属催化剂催化点击反应、Glaser反应、Huisgen [3+2]环加成反应、Heck反应、Suzuki反应、Sonogashira反应、Stille偶联反应、迈克尔加成/脱水串联反应、亲电开环反应、Fridel-Crafts型反应及乙烯聚合反应等,并对存在的问题和发展趋势进行了展望.     

超临界二氧化碳中过渡金属催化有机反应研究进展

主要综述了近年来超临界二氧化碳作为反应介质过渡金属催化有机反应的最新进展.通过与常规有机溶剂中有机反应的对比,着重介绍了超临界二氧化碳作为反应介质在有机反应中所显示出的优越性,例如调控反应的选择性,提高反应速度和增加催化剂催化效率等.     

Cu(I)催化的多组分反应的研究进展

综述了Cu(I)催化的多组分反应的最新研究进展, 详细地介绍了各个反应的底物要求、反应条件、反应选择性、产率以及机理的研究. 同时, 还讨论了其优缺点, 并对其发展加以展望.     

碱性离子液体在有机合成中的应用研究进展

介绍了碱性离子液体特点及其分类,综述了近年来碱性离子液体作为催化剂和反应介质在有机合成反应的最新研究成果.主要包括:Michael加成、Mannich反应、Knoevenagel缩合、Markovnikov加成、Henry反应、Perkin反应、Heck偶联反应、烷基化、羰基化反应和"中断性"Feist-Benary反应.     

<有机合成化学及近代技术>简介

由徐家业主编、西北工业大学出版社出版(1997)的<有机合成化学及近代技术>与流行的同类书籍通常偏重于介绍有机合成反应或各类有机化合物的合成方法不同.该书在按化合物的分子骨架构成,和官能团的变换为纲简要地介绍有机合成反应的同时,较全面的介绍了各种近代有机合成方法和技术.包括有机合成设计、有机电化学合成、相转移催化技术、固相合成方法和干法合成等.除了通常的加热促进反应之外,还介绍了光促反应、微波促进反应和声波促进反应,以及生物催化剂的应用和仿生合成法等,展示了有机合成的新面貌.针对有机合成的实用性,还特意编写了"有机合成的化工过程开发"一章,是一本别具风格的有机化学参考书.     

分离友好的Mitsunobu反应研究进展

Mitsunobu反应由于反应条件温和、立体选择性好,在有机合成及药物化学研究中被广泛应用.同时,由于氧化膦及肼类等副产物的影响,该反应也是有机合成化学中最难纯化的反应之一.简化分离、提高纯化效率是近年来对Mitsunobu反应改进研究的热点方向.综述了近年来各种简化分离的Mitsunobu反应,重点介绍了各种分离策略的原理、优缺点及在Mitsunobu反应中的应用.希望通过对Mitsunobu反应各种分离策略的介绍,加深读者对基于分离策略的有机合成的了解.     

酶的催化多功能性及其在有机合成中的新进展

介绍了近几年来酶的催化多功能性及其应用于有机合成反应研究的最新进展. 包括酶催化多功能性的几种主要类型和相应催化多功能性在Michael加成、Markovnikov加成、羟醛缩合反应、氧化反应及串联反应中的应用.     

Catalytic Isofunctional Reactions—Expanding the Repertoire of Shuttle and Metathesis Reactions

Transfer hydrogenation, alkene metathesis, and alkyne metathesis possess great value to the synthetic chemistry community. One of the key features of these processes is their reversibility, which can be attributed to the presence of the same number and type of functional groups in both the reactants and products, making these reactions isofunctional. These classic reactions have recently inspired the development of novel shuttle and metathesis reactions that offer great promise for synthetic chemistry. This Review describes and systematically categorizes both recent and older examples of shuttle and metathesis reactions other than transfer hydrogenation and alkene/alkyne metathesis.     

Synthesis of nonracemic allylic hydroxy phosphonates via alkene cross metathesis

Allylic hydroxy phosphonates and their derivatives can be interconverted by using cross metathesis with second generation Grubbs catalyst. The absolute stereochemistry of the starting phosphonate is conserved in the product. Cross metathesis reaction of the acrolein-derived phosphonate 2a yields a series of functionalized allylic hydroxy phosphonates. However, the cross metathesis reaction is often accompanied by competing dimerization and alkene migration reactions leading to a reduction in yield. The cinnamaldehyde- and crotonaldehyde-derived phosphonates 2b and 2c were also examined. In general, the metathesis reactions of phosphonates 2b and 2c are considerably slower than those for phosphonate 2a leading to mixtures. Several hydroxyl-protected derivatives of the phosphonate 2a (methyl carbonate 3a, acetate 4a, N-tosyl carbamate 5a, TBDMS 6a, and acetoacetate 7a) undergo metathesis without competing side reactions to give substituted allylic phosphonates in good to excellent yield.     

Improved ruthenium catalysts for Z-selective olefin metathesis

Several new C-H-activated ruthenium catalysts for Z-selective olefin metathesis have been synthesized. Both the carboxylate ligand and the aryl group of the N-heterocyclic carbene have been altered and the resulting catalysts evaluated using a range of metathesis reactions. Substitution of bidentate with monodentate X-type ligands led to a severe attenuation of metathesis activity and selectivity, while minor differences were observed between bidentate ligands within the same family (e.g., carboxylates). The use of nitrato-type ligands in place of carboxylates afforded a significant improvement in metathesis activity and selectivity. With these catalysts, turnover numbers approaching 1000 were possible for a variety of cross-metathesis reactions, including the synthesis of industrially relevant products.     

Electrochemically reduced tungsten‐based active species as catalysts for cross‐metathesis reactions: cross‐metathesis of non‐functionalized olefins

The electrochemical reduction of WCl₆ results in the formation of an active olefin (alkene) metathesis catalyst. The application of the WCl₆–e^?–Al–CH₂Cl₂ catalyst system to cross‐metathesis reactions of non‐functionalized acyclic olefins is reported. Undesirable reactions, such as double‐bond shift isomerization and subsequent metathesis, were not observed in these reactions. Cross‐metathesis of 7‐tetradecene with an equimolar amount of 4‐octene generated the desired cross‐product, 4‐undecene, in good yield. The reaction of 7‐tetradecene with 2‐octene, catalyzed by electrochemically reduced tungsten hexachloride, resulted in both self‐ and cross‐metathesis products. The cross‐metathesis products, 2‐nonene and 6‐tridecene, were formed in larger amounts than the self‐metathesis products of 2‐octene. The optimum catalyst/olefin ratio and reaction time were found to be 1 : 60 and 24 h, respectively. The cross‐metathesis of symmetrical olefins with α‐olefins was also studied under the predetermined conditions. Copyright © 2003 John Wiley & Sons, Ltd.     

The activity of covalently immobilized Grubbs–Hoveyda type catalyst is highly dependent on the nature of the support material

A Hoveyda-type catalyst for olefin metathesis was synthesized and covalently attached via an amide bond to four different solid supports. One of these supports was a home-made hybrid silica support, where an ultra-thin copolymer of poly(styrene) and poly(acrylamide) was grafted on. The three other supports were commercially available, namely HypoGel 400, PEGA and Trisoperl. It was demonstrated that the catalysts were active in ring closing metathesis (RCM) reactions as well as in cross metathesis (CM) and ring opening metathesis (ROM) reactions, but the activity of the catalyst was highly dependent on the nature of the support.     

A general model for selectivity in olefin cross metathesis

In recent years, olefin cross metathesis (CM) has emerged as a powerful and convenient synthetic technique in organic chemistry; however, as a general synthetic method, CM has been limited by the lack of predictability in product selectivity and stereoselectivity. Investigations into olefin cross metathesis with several classes of olefins, including substituted and functionalized styrenes, secondary allylic alcohols, tertiary allylic alcohols, and olefins with alpha-quaternary centers, have led to a general model useful for the prediction of product selectivity and stereoselectivity in cross metathesis. As a general ranking of olefin reactivity in CM, olefins can be categorized by their relative abilities to undergo homodimerization via cross metathesis and the susceptibility of their homodimers toward secondary metathesis reactions. When an olefin of high reactivity is reacted with an olefin of lower reactivity (sterically bulky, electron-deficient, etc.), selective cross metathesis can be achieved using feedstock stoichiometries as low as 1:1. By employing a metathesis catalyst with the appropriate activity, selective cross metathesis reactions can be achieved with a wide variety of electron-rich, electron-deficient, and sterically bulky olefins. Application of this model has allowed for the prediction and development of selective cross metathesis reactions, culminating in unprecedented three-component intermolecular cross metathesis reactions.     

Iron‐Catalyzed Ring‐Closing C−O/C−O Metathesis of Aliphatic Ethers

Among all metathesis reactions known to date in organic chemistry, the metathesis of multiple bonds such as alkenes and alkynes has evolved into one of the most powerful methods to construct molecular complexity. In contrast, metathesis reactions involving single bonds are scarce and far less developed, particularly in the context of synthetically valuable ring‐closing reactions. Herein, we report an iron‐catalyzed ring‐closing metathesis of aliphatic ethers for the synthesis of substituted tetrahydropyrans and tetrahydrofurans, as well as morpholines and polycyclic ethers. This transformation is enabled by a simple iron catalyst and likely proceeds via cyclic oxonium intermediates.     

Allenyl esters as quenching agents for ruthenium olefin metathesis catalysts

In the attempt to synthesize substituted allenyl esters through a metathesis coupling of unsubstituted allenyl esters and alkenes using a variety of ruthenium catalysts, it was discovered that allenyl esters themselves cleanly arrested the activity of the catalysts. Further studies suggests possible utility of allene esters as general quenching agents for metathesis reactions. To explore this idea, several representative olefin metathesis reactions, including ring closing, were successfully terminated by the addition of simple allenyl esters for more convenient purification.     

In-plane enyne metathesis and subsequent Diels-Alder reactions on self-assembled monolayers

We report in-plane enyne metathesis and subsequent Diels-Alder reactions on self-assembled monolayers (SAMs) terminating in vinyl and acetylenyl groups on gold. After the formation of SAMs of vinyl and acetylenyl group-containing dithiols on gold, in-plane enyne metathesis of the vinyl and acetylenyl groups, leading to the formation of 1,3-diene, was achieved on the SAMs, and Diels-Alder reactions were then successfully performed with tetracyanoethylene, maleic anhydride, and maleimide. The reactions were confirmed by FT-IR spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary-ion mass spectrometry. In-plane enyne metathesis developed herein would offer a versatile platform for the functionalization of surfaces with mild reaction conditions and a high compatibility in functional groups.     

Synthetic studies of quinolizidine 195C and derivatives

Sulfur-substituted dihydropyridones prepared by aza-Diels–Alder reactions were converted to the cis-2,6-disubstituted derivatives, which could then proceed through ring-closing metathesis (RCM) and cross metathesis (CM) reactions to give many quinolizidine derivatives, including two epimers of (±)-195C.