联炔环化反应研究进展

联炔是一种具有较高反应活性的有机合成中间体,与单炔相比联炔具有共轭结构和更多的反应活性位点,既能够作为四合成子构建单环化合物,也能够发生串联环化反应形成多环化合物,因此成为有机化学家的研究热点。本文综述了近年来联炔环化反应的研究进展,并对该领域未来的发展方向进行了展望。     

钯催化的乙炔烷氧化物的环化和交叉偶合反应

钯催化的乙炔醇化物的环化已表明是合成各种杂环的有效方法,但钯催化的从炔醇立体选择性合成呋喃叉或吡喃叉化合物还未见开发,本文报道了钯催化的用各种有机卤化物使炔醇的环化和交叉偶合反应的新策略.     

新型丁二炔-二酰胺大环化合物的合成及与TTF和DNP在溶液中的络合行为

由三甘醇和四甘醇出发,经炔丙基烷基化、Mitsunobu反应和Eglinton偶联反应3步合成了2个含均苯四甲酸二酰亚胺结构单元以及丁二炔结构单元的大环化合物,关环产率分别为81%和85%.大环化合物及中间体的化学结构经核磁共振氢谱、碳谱、低分辨质谱、高分辨质谱或元素分析等确认.通过氘代丙酮中1HNMR实验以及氯仿中紫外滴定实验研究了这类大环化合物与客体分子四硫富瓦烯(TTF)和1,5-二甲氧基萘(DNP)在溶液中的相互作用,结果发现,大环化合物的核磁化学位移及紫外光谱均发生变化.通过得到的主-客体间的络合常数可知,此类新型大环化合物与TTF和DNP之间有一定的络合作用.     

基于硅烷化启动的环化反应研究进展

有机硅化合物是许多材料的重要基元和有用的有机分子,是化学合成中用途广泛的合成中间体.因此,化学家们一直致力于开发构建含硅化学键的新方法,特别是C—Si键.自从Sakurai和Imai在1975年报道了第一个钯催化的硅环丁烷与炔的环加成反应以来,过渡金属催化硅基环化反应得到了迅速的发展.随着自由基反应的迅猛发展,研究者将其拓展到有机硅分子间环化反应,硅的环化反应迎来了新的发展.主要从过渡金属催化的硅环化反应、自由基引发的硅环化反应、C+离子引发的硅环化反应展开讨论,最后对当前的研究进展进行了总结.     

过渡金属催化的多炔基化合物高选择性亲电环异构化反应研究

对我们研究小组近几年来在过渡金属催化的复合炔基化合物的高选择性环异构化反应方面取得的成果进行了小结.通过底物与亲电试剂的分子间串联亲电环化反应,有效地构建了官能团化的苯并[a]芴醇和密集三取代的卤代炔基萘酮环结构单元衍生物.基于此研究基础,又发展了一类过渡金属催化的1,6-二炔醇酯或1,5-二炔类化合物的分子内环异构化反应,构建了官能团化的亚甲基茚结构单元以及含三氟甲硫基结构的茚衍生物.此外对影响反应的可能因素也做了讨论,提出了可能的反应机理.     

含四硫富瓦烯大环化合物的合成与研究进展

简要介绍了含有四硫富瓦烯(TTF)单元的大环化合物的分类, 概括了各类含四硫富瓦烯大环化合物的合成方法, 主要包括含有1,3-二硫杂环戊烯-2-硫酮单元的大环化合物在亚磷酸三烷基酯参与下的偶合反应, 以及带有氰乙基硫等取代基的预先合成的官能化TTF与二卤代低聚醚的反应. 综述了含四硫富瓦烯大环化合物的电化学性能及其在分子识别方面应用研究的最新进展, 提出了含四硫富瓦烯大环化合物的发展趋势.     

邻炔苯基膦酸单酯的环化偶联反应研究

许多异香豆素类的化合物都具有良好的生物活性,例如可以用作丝氨酸酶的不可逆抑制剂、抗菌剂.天然羧酸的膦酸类似物很可能具有与羧酸类似的生物活性.我们通过邻炔苯基膦酸单酯的环化反应合成了磷异香豆素类化合物,初步的活性测试显示此类化合物具有一定的生物活性.为了进一步了解分子内膦酸和炔的加成反应的应用价值和得到更多的磷异香豆素衍生物以研究其生物活性,我们对邻炔苯基膦酸单酯的环化偶联反应作了初步的探索,与溴丙烯的反应取得了比较满意的效果,和其他的亲电试剂的串连式环化偶联反应正在研究中.     

新型四炔模块苯炔前体高效构建咔唑类衍生物

采用卡迪奥-肖德凯维奇偶联反应合成了一系列的四炔类的化合物, 随后利用这些新型四炔模块苯炔前体高效地合成了一系列咔唑类衍生物. 此外, 银具有很好的催化活性, 当加入催化量的AgNO₃到反应体系中时, 通过一步反应能够获得同时含有咔唑环和吲哚环的多元杂环化合物. 更重要的是, 这些反应具有很高的产率. 此外, 这类反应的底物适用性是非常广的. 并且提出了涉及到AgNO₃催化的N-H插入反应的可能的机理.     

无过渡金属催化2-重氮-3,5-二氧代-6-炔酯/炔酮/炔酰胺的区域选择性逆转环化:重氮γ-吡喃酮和重氮3(2H)-呋喃酮衍生物的合成

在六氟锑酸/乙醇的体系中,80℃条件下,2-重氮-3,5-二氧代-6-炔酯/炔酮/炔酰胺环化生成重氮γ-吡喃酮衍生物;然而,在乙酸/三乙胺/1,2-二氯乙烷体系中,25℃条件下,其环化反应主要生成重氮3(2H)-呋喃酮.在Rh(II)催化下,这些重氮化合物与烯烃可以进行有效的分子间环丙烷化.     

炔烃分子内环化反应合成含氮杂环化合物研究进展

分子内氮原子参与的炔烃环化反应是构成含氮杂环化合物(例如吲哚类化合物等)的最重要途径之一. 从两个方面对分子内氮杂原子与炔的环化反应研究新进展进行了综述: 过渡金属催化分子内环化反应和分子内亲电环化反应. 此外, 对环化反应的机理也做了较详细的描述.     

An Efficient Synthetic Strategy for Construction of Functionalized Pentacyclic Skeleton of ecteinascidin-saframycin Alkaloids

Ecteinascidin 743 (Et 743, 1) is an extremely potent antitumor alkaloid isolated from the marine tunicate Ecteinascidia turbinate. It is currently undergoing phase Ⅱ/Ⅲ clinical trials1. In view of its novel structure, the lack of availability and unique mechanism of action, Et 743 has attracted extensive synthetic studies during the past decade, culminating in the first stereoselective total synthesis by E. J. Corey and co-workers in 1996 and another total synthesis by Fukuyama and co-work…     

Oxidative Coupling of 1,7,8-Unsubstituted BODIPYs: Synthesis and Electrochemical and Spectroscopic Properties

We report the synthesis of BODIPYs with unsubstituted 1,7,8-positions and their dimerization by oxidative coupling with phenyliodine(III)-bis(trifluoroacetate) (PIFA). This dimerization was achieved for BODIPYs substituted in the 3,5-positions with either methyl or thienyl groups. The position and the type of the linkage in the resulting dimers depended on the nature of the substituent. The 3,5-dimethyl-BODIPY dyes were linked either via direct 1,1'-pyrrole-pyrrole coupling or via a 1,3'-methylene bridge. The 3,5-dithienyl-BODIPY dyes provided, in excellent yields, unique compounds linked exclusively via the α-thienyl positions. All dyes were unreactive in the 8-position. Electrochemical and spectroscopic measurements on the monomers and dimers provided evidence of interactions between the two halves of the dimers. Thus, oxidation and reduction potentials were split by up to 210 mV, and modest excitonic coupling and an internal charge transfer were observed in some cases.     

三组分串联反应一锅合成多环稠合的1,5-苯并二氮杂䓬化合物

以取代的邻苯二胺、1,3-环戊二酮或1,3-环己二酮(5,5-二甲基-1,3-环己二酮)、2,3-二羰基化合物为原料,无水乙醇为溶剂,对甲苯磺酸为催化剂,经2~5 h串联反应一锅合成43种新颖的1,5-苯并二氮杂?化合物,产率最高可达95%.该反应序列首先通过两次的亲核加成-脱水反应过程,形成分子内亚胺和烯胺结构的活性中间体,然后再经分子内的碳碳偶联环合-质子转移等过程,生成多环稠合的1,5-苯并二氮杂?目标化合物,实现了在一个反应体系中形成一个二氮杂七元环和四个新化学键(两个C—N,一个C=C,一个C—C).该方法操作简单,反应便捷,对环境友好,产率高,为1,5-苯并二氮杂?化合物的合成提供绿色环保,高效简便的合成思路.     

Ferrocene-modified pyrimidine nucleosides: synthesis, structure and electrochemistry

This paper reports syntheses, crystal structures and electrochemical results for two ferrocene(Fc)-modified pyrimidine nucleosides that could potentially be used for investigating electron transfer in DNA. Fc was directly attached to the 5-position of deoxyuridine and deoxycytidine via the Stille coupling reaction. Fc-modified uridine was incorporated into DNA trinucleotides with standard solid-phase synthesis. The structures of corresponding detritylated compounds were determined by single-crystal X-ray analysis. Electrochemical investigations of all compounds by cyclic voltammetry revealed reversible redox processes.     

Electronic influences on 3J(C,H) coupling constants via -S-, -S(O)- and -SO2-: their determination, calculation and comparison of detection methods

3J(C,H) coupling constants via a sulfur atom in two series of compounds, both including a sulfide, a sulfoxide and a sulfone, were detected experimentally and calculated by quantum mechanical methods. In the first series (1-3) the coupling between a hydrogen, bonded to an sp3 carbon, and an sp2 carbon is treated; the second series (4-6) deals with the coupling between a hydrogen, bonded to an sp3 carbon, and an sp3 carbon. Different pulse sequences (broadband HMBC, SelJres, 1D HSQMBC, J-HMBC-2, selective J-resolved long-range experiment and IMPEACH-MBC) proved to be useful in determining the long-range 3J(C,H) coupling constants. However, the dynamic behaviour of two of the compounds (4 and 6) led to weighted averages of the two coupling constants expected (concerning equatorial and axial positions of the corresponding hydrogens). DFT calculations proved to be useful to calculate not only the 3J(C,H) coupling constants but also the different contributions of FC, PSO, DSO and SD terms; the calculation of the Fermi contact term (FC) was found to be sufficient for the correct estimation of 3J(C,H) coupling constants.     

A two step synthesis of 2-oxo-2-vinyl 1,3,2-dioxaphospholanes and -dioxaphosphorinanes

The title compounds are prepared via a two step procedure involving a transesterification between a diol and diethyl phosphite followed by a palladium-catalyzed coupling of the so-obtained cyclic phosphite with vinyl bromide. Theoretical DFT calculations have been performed on phosphonate and phosphite anions models in order to estimate stereoelectronic effects in five-membered and six-membered ring compounds.     

Solution- and solid-phase syntheses of substituted guanidinocarboxylic acids

A library of guanidine-based compounds was produced to mimic the lead compound 1, which is a substance known to have intensely sweet-taste characteristics. Libraries of guanidinocarboxylic acids were therefore prepared via two synthetic methods. The solid-phase method involving trapping of solution-phase carbodiimides by supported amines was used to produce N,N'-dialkyl derivatives (Scheme 1). The second solid-phase method, featuring supported carbodiimides and solution-phase amines (Scheme 2), was devised to prepare N,N'-disubstituted and N,N',N'-trisubstituted guanidinocarboxylic acids. A small collection of guanadinoacetic acid dimers and trimers was also prepared, but this time via a solution-phase coupling of carbodiimides to a polyamine linker.     

Oxidative coupling as a potential route to polymers of group IV acetylenes

Bis tert-butyl-, trimethylsilyl- and trimethylgermyl-diacetylenes were prepared from the corresponding ethynyl Group IV compounds via oxidative coupling. Bis(trimethylstannyl)diacetylene could not be prepared by oxidative coupling, but was prepared via another technique. Coupling of diethynyldimethylsilane did not lead to the expected polymer, as cleavage of the silicon–ethynyl bond occurred. However, coupling of 1,3-bis(dimethylethynyl)disiloxane did lead to polymer containing alternating diacetylene and disiloxane units.     

Synthesis of 6/7-Halotetralones

The title compounds were prepared from halobromobenzenes via a palladium catalysed coupling followed by cyclisation.     

消耗性镁阳极在有机电合成中的应用(I)——羰基化合物的还原偶联

羰基化合物的还原偶联是形成C-C键的重要方法.早在本世纪初,有人就研究了醛酮的电解还原偶联反应,但所用的电极为Hg、Pd、Pt、Cd等,且电解过程有诸多不便.八十年代中期出现了一种以消耗性金属Mg、Al、Zn为阳极,石墨等为阴极的有机电极合成方法[1].