硫含氧酸盐引发的氟烷基化内酯化反应

内酯官能团广泛存在于天然产物和生理活性化合物中,而含氟基团或氟原子的引入会对有机分子的理化性质、生理活性等产生显著的影响[1],所以含氟内酯化合物的合成一直是许多科学家感兴趣的课题.我们建立了一个通过连二亚硫酸钠引发含氟碘代烷与烯酸合成含氟内酯的新方法[2].本工作继续对其它硫含氧酸盐引发的氟烷基化内酯化反应进行深入研究.     

Goniothalamin内酯含氟修饰物合成研究进展

Goniothalamin是由番荔枝科(annonaceae)家族中分离出的抗肿瘤活性天然产物分子,具有苯乙烯基及α,β-不饱和-δ-内酯两个关键片段。药物化学家近年来利用氟原子或者含氟基团对这两个关键药效基团进行了系统的结构修饰,试图利用氟独特的物理化学性质调控药效基团电子属性以获取具有更佳生理活性的化合物。本文主要从含氟基团引入的位点设计以及合成方法角度,总结了goniothalamin内酯含氟修饰物合成与生理活性研究进展,并进行了发展前景展望。     

α,α-二氟-γ-丁内酯化合物的合成研究

内酯化合物是天然存在的一类具有生物活性的化合物.而含氟基团或氟原子的引入对有机分子的理化性质、生理活性等会产生显著的影响[1],所以含氟内酯化合物的合成一直是许多科学家感兴趣的课题.我们曾利用多氟烷基碘代烷与4-戊烯酸反应得到了含氟内酯化合物[2].由于二氟甲基的取代效应与醚链相似[3],因此研究α,α-二氟-y-丁内酯的合成具有其特殊的重要意义.     

含氟苯甲酰基硫脲的合成及生物活性研究

以含氟苯甲酸为原料, 经酰氯化、酰化得到含氟苯甲酰基异硫氰酸酯, 再与取代2-氨基嘧啶或2-氨基吡啶进行加成反应, 合成了12种未见文献报道的含氟苯甲酰基硫脲化合物, 探讨了影响加成反应的主要因素, 产物结构经1H NMR, IR, GC-MS和元素分析确证. 初步生物活性测试结果表明: 当浓度为1 mg/L时, 部分目标化合物具有较好的植物生长调节活性, 讨论了间氟苯甲酰基硫脲类化合物的生物活性与其分子结构之间的相关性.     

光促进的山道年重排反应在复杂萜类天然产物全合成中的应用

萜类化合物在自然界中广泛存在,其中倍半萜内酯广泛存在于各种药用植物中,是许多传统中草药的主要活性成分,然而这类化合物的化学全合成却极具挑战性.山道年是一种廉价的可再生资源,且光促进的山道年重排反应是一种构建愈创木内酯骨架的高效方法,在萜类天然产物合成中得到广泛应用.就光促进的山道年重排在复杂萜类天然产物的合成工作进行简单的概述,主要包括倍半萜内酯及其寡聚物全合成以及个别二萜天然产物的骨架合成研究.     

含氟卟啉的研究进展

综述了近几年国内外含氟卟啉的合成及其研究进展. 含氟卟啉合成方法分为直接氟化法和间接氟化法. 直接法主要采用无机氟化试剂直接对卟啉环进行氟化; 间接法主要采用含氟砌块法引入氟基团. 由于合成卟啉环比较复杂, 目前氟化学家主要采用间接氟化法合成含氟卟啉化合物.     

含氟苯甲酰基硫脲的合成及生物活性研究

以含氟苯甲酸为原料,经酰氯化、酰化得到含氟苯甲酰基异硫氰酸酯,再与取代2-氨基嘧啶进行加成反应,合成了3种含氟苯甲酰基硫脲化合物,优化了反应条件。产物的结构经IR、GC-MS和1H-NMR确证。初步生物活性测试结果表明:当质量浓度为100mg/L时,部分目标产物具有较好的植物生长调节活性。     

含氟β-氨基酸及其衍生物的合成进展

含氟β-氨基酸及其衍生物具有特殊的生理活性, 其合成方法的研究近年来受到广泛关注. 以直接氟化法和间接氟化法分类, 概述了含氟β-氨基酸及其衍生物的合成方法及最新研究进展, 对一些已知化合物的生理活性及药用价值作了初步归纳.     

离子液体中钯催化烯烃串联碳酯化构建官能团化的β和γ-内酯

正β-和γ-内酯作为关键母核结构单元广泛存在于具有生理活性的天然产物以及药物分子中.另外,作为有机合成中重要的合成子,β-和γ-内酯的结构单元也被广泛应用于合成结构复杂的多官能团以及稠环化合物.然而,已报道的合成方法中,在某种程度上存在着诸如反应条件苛刻、使用有毒溶剂或催化剂以及底物官能团兼容性窄等缺点,极大地限制了其广泛应用.因此,随着绿色化学与环境友好化学的发展,探寻简洁、高效以及绿色的构建β和γ内酯骨     

自由基介导含氟杂环化合物的构建研究

含氟杂环化合物由于其优异的物理化学性质,在有机化学、药物化学、材料科学等诸多领域扮演着重要的角色.但自然界中,天然含氟杂环化合物屈指可数,开发高效的含氟杂环化合物的合成方法显得尤为重要.随着过渡金属催化、光催化以及电催化自由基反应的迅速发展,自由基化学在合成领域取得了突破性进展,激发了有机化学家利用自由基化学构建含氟杂环的兴趣.主要以不饱和烃的单氟烷基化、二氟烷基化、三氟甲基化、三氟烷氧/硫/硒基化、全氟烷基化以及杂环的直接C—H氟烷基化进行分类,从过渡金属催化、光催化以及电催化等几个方面,对自由基介导的含氟侧链杂环化合物的构建进行讨论.     

Stereodivergent and Protecting‐Group‐Free Synthesis of the Helicascolide Family: A Rhodium‐Catalyzed Atom‐Economical Lactonization Strategy

Natural products of polyketide origin, in particular small‐sized lactones often possess a very broad range of impressive biological activities. An efficient way to demonstrate the concise access to six‐membered lactones was emphasized as part of a stereodivergent and protecting‐group‐free synthesis of all three representatives of the helicascolide family. This strategy features an atom‐economical and highly diastereoselective rhodium‐catalyzed “head‐to‐tail” lactonization by an intramolecular addition of ω‐allenyl‐substituted carboxylic acids to terminal allenes, including the selective construction of a new stereocenter in the newly formed core structures. The excellent selectivities with which the helicascolide precursors were obtained are remarkable, thus resulting in an expeditious and highly efficient natural product synthesis.     

Synthesis of β‐Methoxyacrylate Natural Products Based on Box‐PdII‐Catalyzed Intermolecular Methoxycarbonylation of Alkynoles

Bis(oxazoline)‐palladium(II) catalyzed carbonylation of homopropargyl alcohols afforded acyclic methoxyacrylate 2 and 6‐membered lactone 3a , 3b , 3d , 3e , 3f , 3g , 3h , 3i , 3j , 3k in good combined yield. In the case of propargyl alcohols, 5‐membered lactones 3p , 3q , 16 were obtained in moderate yields. The one‐pot synthesis of kawa lactones 3a , 3r , 3s and formal synthesis of dihydroxycystothiazole A and dihydroxycystothiazole C are presented. To elucidate the stereochemistry of (+)‐annularin G and (?)‐annularin H, the first asymmetric syntheses of these natural products were achieved.     

A Morita-Baylis-Hillman adduct allows the diastereoselective synthesis of styryl lactones

We disclosed herein a diastereoselective approach for the total syntheses of (±)-Leiocarpin A and (±)-Goniodiol. These biologically active styryl lactones were obtained from a common intermediate, prepared in five steps and 40% overall yield, using a simple synthetic sequence starting from a Morita-Baylis-Hillman adduct. The total syntheses of these styryl lactones were accomplished in nine steps. This is the first report on the total synthesis of this class of natural products starting from Morita-Baylis-Hillman adduct.     

α,β-不饱和内酯的光化学反应研究进展

α,β-不饱和内酯的光化学反应可广泛应用于核苷、稠环生物碱、萜类、甾类等多种光学活性物质与天然产物的合成中.根据不同的反应类型,综述了2(5H)-呋喃酮等α,β-不饱和内酯的光化学1,4-加成反应、1,4-加成-并环反应、[2+2]环加成反应和复杂环加成反应的新进展.     

Studies toward the total synthesis of sorangiolides and their analogues. A convergent stereoselective synthesis of the macrocyclic lactone precursors

Stereoselective synthesis of the fully protected 18-membered macrocyclic lactones as the immediate precursors of the natural products, sorangiolides A and B, is described. The key steps used in the synthesis include the sp3-hybridized carbon-carbon Fu cross coupling, the stereoselective Evans' aldol reaction with 1,5-anti induction, the 1,3-diastereoselective syn reduction of a beta-hydroxyketone intermediate, and Mukaiyama macrolactonization reactions.     

Regioselective route for arylnaphthalene lactones: convenient synthesis of taiwanin C,justicidin E,and daurinol

Arylnaphthalene lactones are natural products which can be isolated from a wide range of plants and have the significant biological activities including cytotoxicity, antimicrobial, diuretic, and ion channel blocking. The drawback of the previous intramolecular Diels–Alder reaction of 3-arylprop-2-ynyl 3-arylpropiolates was to generate two regioisomers of arylnaphthalene lactone without selectivity. Herein, we report a convenient and regioselective synthesis method in which the intramolecular Diels–Alder reaction of an arylalkene–arylalkyne and subsequent DDQ oxidation was used for Type I and Type II arylnaphthalene lactones, respectively. We demonstrated the synthesis of three lignans, taiwanin C (Type I), justicidin E (Type II), and daurinol (Type I and anti-cancer activity).     

Total Synthesis of Resorcylic Acid Lactone (−)-Neocosmosin A Using Palladium-Catalyzed α-Arylation of Enones as the Key Step

The total synthesis of the 14-membered resorcylic acid lactone neocosmosin A is described. The key step in the synthesis is the palladium-catalyzed α-arylation of TES-enol ethers of enones. The employment of the α-arylation approach to this class of resorcylic acid lactones is a new approach, which has the scope of being generalized into a unified approach for the synthesis of this class of natural products.     

Enantiospecific synthesis of (+)-N(a)-methylpericyclivine and (-)-N(a)-methylakuammidine as well as the ring-A oxygenated natural products, (+)-10-methoxy N(a)-methylpericyclivine and 10-hydroxy N(a)-methylpericyclivine

[reaction: see text] The first enantiospecific, regiospecific total synthesis of the enantiomers of N(a)-methylpericyclivine and N(a)-methylakuammidine as well as the ring-A oxygenated natural products (+)-10-methoxy N(a)-methylpericyclivine and 10-hydroxy N(a)-methylpericyclivine was achieved. The lactones (see 19, 22, and 25) are key to the formation of the beta-axial methyl ester moiety.     

Silver-catalyzed one-pot synthesis of arylnaphthalene lactones

Arylnaphthalene lignan lactones are valuable natural products with promising anticancer and antiviral properties. In an effort to simplify their synthesis, we investigated a one-pot multicomponent coupling reaction between phenylacetylene, carbon dioxide, and 3-bromo-1-phenyl-1-propyne. After the corresponding 1,6-diyne was generated in situ, cyclization afforded the desired product. The level of regioselectivity was enhanced through the tuning of electronic properties. The use of cinnamyl bromide which led to the formation of a 1,6-enyne intermediate was also studied.     

Inverse-Electron-Demand Diels–Alder Reactions of 2-Pyrones: Bridged Lactones and Beyond

Inverse-electron-demand Diels–Alder (IEDDA) reactions of electron-poor 2-pyrones as electrophilic dienes have been extensively studied in the past fifty years. These reactions provide an efficient access to bridged bicyclic lactones and their derivatives, such as densely functionalized 1,3-cyclohexadienes after CO₂ extrusion and polysubstituted aromatic compounds through elimination. This reaction has been used for the synthesis of many biologically active natural products and drug candidates. In this review, the developments of these IEDDA reactions including non-catalytic, Lewis acid-catalyzed and organocatalytic IEDDA reactions, and their applications in total synthesis are discussed in detail.