分子内Friedel-Crafts环化反应在苯并环状物合成中的应用

Friedel-Crafts反应是有机合成中最有用的反应之一,它的应用范围十分广泛.Friedel-Crafts反应也是合成环状化合物的重要途径,尤其分子内的环化反应一直以来受到广泛的关注.对近年来应用分子内Friedel-Crafts环化反应合成苯并环状化合物进行了详细的综述,并对分子内Friedel-Crafts环化反应在有机合成上发展前景作了展望.     

过渡金属催化烯丙醇异构化反应的研究进展

羰基化合物是一类重要的有机合成中间体,其在医药、农药、香料和化妆品领域具有重要应用.近年来,利用烯丙醇异构化反应快速合成一系列羰基化合物和构建新化合物的方法受到化学家的广泛关注.由于过渡金属催化的烯丙醇异构化反应具有良好的原子经济性,在合成方面具有独特的优势,烯丙醇异构化反应成为金属有机化学研究的热点之一.综述了近年来过渡金属催化的烯丙醇异构化反应的研究进展和应用.     

有机合成反应的重要工具书——《现代合成反应》评介

现代合成化学的发展十分迅速,据统计,世界上每天合成的新化合物有上千个之多,而其中绝大多数是新的有机化合物。新的有机合成反应及合成方法更是层出不穷。有机合成不仅是一门科学,从某种意义上说也是一门艺术。本书著者H.O.House就是当代一位著名的有机合成艺术家,尤其在活泼氢和羰基化合物等领域,他更有许多突出的研究成果。正因为如     

柑橘生物活性多甲氧基黄酮及其糖苷类的合成研究

多甲氧基黄酮是广泛存在于柑橘属植物中的一类具有显著抗癌、抗炎等生物活性的天然产物.本工作以间苯二酚和甲氧基取代的苯甲醛为原料,经过溴化、甲基化、芳基亲核取代、Friedel-Crafts乙酰化、羟醛缩合、环化或Algar-Flynn-Oyamada反应、DDQ脱氢、选择性脱甲基化反应,以及随后的糖苷化和脱乙酰化反应,合成了一系列多甲氧基黄酮及其糖苷类化合物1a,1b～4a,4b,5～9.其中1a,1b,2a,2b,3b,4a,4b和5～7,9是全合成的天然产物.此外,在对五甲氧基苯的合成过程中,发现了一种由间二苯酚经溴代、甲基化和芳香亲核取代等三步反应高产率制备有机合成中间体2,3,4,6-四甲氧基苯酚(12)的新方法.所合成新化合物的结构由MS,IR,1H NMR和13C NMR进行了表征.     

阴离子相转移催化的Friedel-Crafts烷基化反应

提出三种阴离子表面活性剂十二烷基苯磺酸钠、十二烷基磺酸钠、十二烷基硫酸钠作为阴离子相转移催化剂特性。研究了它们在Friedel-Crafts反应中的催化性能,结果表明它们都有良好的催化特性合成了七个化合物, 其中五个为未见文献报导的新化合物, 它们是二苯甲基萘酚和二苯甲基酚类化合物。     

物理技术辅助的Knoevenagel反应*

Knoevenagel反应的副产物是水,微波、超声波、研磨等物理技术辅助的有机合成方法高效、节能、环保,使物理技术辅助的Knoevenagel反应非常符合绿色化学的要求。目前,Knoevenagel反应被广泛应用于有机合成中,各种物理辅助合成技术的涌现对于提高其产率、简化其操作、扩大其应用范围具有日益重要的作用。同时,利用研磨新技术进行Knoevenagel反应的工业化探索也开始引人注目。本文按微波、超声波、研磨等物理辅助技术的不同,综述了近年来Knoevenagel反应研究的新进展,特别是涉及多组分反应、串联反应的Knoevenagel反应在多杂环化合物合成中的新应用。为了使Knoevenagel反应更加绿色化,可以预见在未来的Knoevenagel反应研究中,基于上述物理技术的利用Knoevenagel反应的合成方法学研究与Knoevenagel反应的工业化研究值得重视。     

2,2-亚戊基-1,3-二氧六环-4,6-二酮与原甲酸三乙酯和芳香胺的反应

剂,在有机合成中已有一定应用。开展Meldrum's 酸系列化合物的研究,旨在:1.寻找有结构特点的新试剂,2.合成一系列新化合物,3.研究新化合物的应用。本文通过控制反应温度(28～29℃)催化剂用量(比文献用量多近一倍),提高了2,2-亚戊基-1,3-二氧六环-4,6-二酮(PDDO,3)的制备得率(由15%     

微波有机合成反应的新进展

综述了近来微波辐射技术在有机合成应用中的新进展。着重介绍了微波有机合 成反应技术及其在重要有机合成反应中的应用。     

微波技术在有机化学反应中的应用

本文介绍了微波技术在干法有机反应、加速有机合成速率及合成短寿命放射性药剂中的应用,概述了微波技术中影响反应速率的因素等,说明了微波特有的能量及快速加热能力在化学反应研究中具有广泛的实际意义。     

缩氨基硫脲的微波无溶剂合成

本文报道了利用微波辅助，以氨基硫脲和芳醛为原料，进行的缩氨基硫脲的合成。此方法简单，高效且环境友好。反应中不需用到溶剂和催化剂。实验证实微波辅助的无溶剂合成在有机合成中有着重要的价值。     

催化不对称Friedel-Crafts反应

傅-克反应是有机化学中最基本的反应之一,但是对于催化的不对称傅-克反应的研究则处于起步阶段。最近这方面的研究获得了突破,本文简要介绍了催化不对称傅-克反应的最新动态,包括各种手性Lewis酸催化体系的开发及其在不对称合成中的应用。     

Dy(OTf)3 Catalyzed Reaction of Indole with Aldehydes and Ketones in Ionic Liquids

The use of environmentally benign reaction media is very important in view of today' s environmentally con scious attitude. In connect with this, room temperature ionic liquids that are air and moisture stable have received a good deal of attention in recent years as novel solvent systems for organic synthesis. A number of reactions such as Friedel-Crafts reactions, Diels-Alder cycloadditions, hydrogenations, and Heck reactions have employed ionic liquids as solvents. Among them, the Friedel-Crafts reaction[1] is of great synthetic significance in view of laboratory synthesis and industrial production. Recent studies showed that Friedel-Crafts reaction of indole with carbonyl compounds proceeded readily in aqueous media. [2] However, the aqueous reactions suffer from some common problems,such as tedious work-up, reuse of catalyst and so on.     

1-dodecyloxy-4-perfluoroalkylbenzene as a novel efficient additive in aldol reactions and Friedel-Crafts alkylation in supercritical carbon dioxide

[reaction: see text] 1-Dodecyloxy-4-perfluoroalkylbenzenes accelerated organic reactions such as aldol-type reactions and Friedel-Crafts alkylation in supercritical carbon dioxide. The perfluoroalkylbenzene worked as a surfactant in the system, and formation of emulsions during the reactions was observed.     

Friedel-Crafts acylation with amides

Friedel-Crafts acylation has been known since the 1870s, and it is an important organic synthetic reaction leading to aromatic ketone products. Friedel-Crafts acylation is usually performed with carboxylic acid chlorides or anhydrides, while amides are generally not useful substrates in these reactions. Despite being the least reactive carboxylic acid derivative, we have found a series of amides capable of providing aromatic ketones in good yields (55-96%, 17 examples). We propose a mechanism involving diminished C-N resonance through superelectrophilic activation and subsequent cleavage to acyl cations.     

Microwave-assisted silica-supported aluminum chloride-catalyzed Friedel-Crafts alkylation

Microwave irradiation is a popular method in organic synthesis to achieve high yields in shorter reaction times. This decreases total ‘man-hours’ in a synthetic setting. Another technique used in organic chemistry to decrease manual manipulations, is solid support reagents. The benefits of this approach is that upon completion of a reaction, a simple filtration can be performed which expedites the work-up and also produces less organic waste. Friedel-Crafts alkylation has been explored using microwave chemistry as well as with solid-supported reagents. In comparison with traditional heating, as well as with AlCl₃, superior yields were observed with silica-gel bound aluminum chloride (Si-AlCl_x) when microwave irradiated for only 5 min.     

Application of physical organic methods to the investigation of organometallic reaction mechanisms

For the past 75 years, physical organic chemistry has been the foundation for the elucidation of mechanisms, and the understanding of structure/activity relationships, in organic chemistry. The rational design of experiments and the critical analysis of data have been the hallmarks of this field. In this Perspective, we revisit some of the studies carried out during the past 30 years in which our group has used the tools of physical organic chemistry to investigate the mechanisms of a variety of organometallic reactions. The Perspective covers a broad spectrum of metal-mediated reactions including organic reductions, alkene, carbon monoxide and nitric oxide migratory insertion reactions, C-H bond activation, and the reactions of metal-heteroatom bonds with organic molecules. These studies, along with similar ones carried out in other groups, have demonstrated that the principles and methods of physical organic chemistry have adapted well to the study of organometallic reaction mechanisms. The understanding obtained in this way has aided the development of useful metal-mediated reactions in a wide range of areas, especially in industrial catalysis and in applications to problems in organic synthesis.     

金属有机化学中的绿色化学反应进展

着重综述了金属有机化学领域中所涉及的与绿色化学概念有关的一些化学反应,如水相反应、超临界流体及离子液体中的反应、固态反应、原子经济性及过渡金属催化的有机反应。     

Synthetic methods and reactions

This review deals with the development of a series of reagents and reactions for organic synthesis using simple starting materials. A wide array of carbocationic and onium ion reagents, halogenating agents, Friedel-Crafts catalysts, metal-induced oxidationreductions and silicon reagents were utilized in basic (unit) reactions, which serve as building blocks for general synthetic transformations. Considered synthetic methods and reactions. Part 131. For part 130 see: M B Sassaman, K D Kotian, G K S Prakash and G A Olah. 1987J. Org. Chem. 52 4314.     

One-pot synthesis of 2-bromo-4,5-diazafluoren-9-one via a tandem oxidation-bromination-rearrangement of phenanthroline and its hammer-shaped donor-acceptor organic semiconductors

An unexpected one-pot tandem procedure of 2-bromo-4,5-diazafluoren-9-one starting from phenanthroline with a yield of up to 50% has been described. The conversion mechanism involves three consecutive oxidation, bromination, and rearrangement reactions. A series of its hammer-shaped donor-acceptor organic semiconductors with solvent-dependent fluorescence have also been constructed via Ullman and/or Friedel-Crafts reaction. Diazafluorenes (DAFs) and derivatives are regarded as promising building blocks or candidates for donor-acceptor organic semiconductors.