Phebaclavin C的全合成研究

天然存在的香豆素类化合物具有良好的生理活性和光学活性[1].PhebaclavinA～H是2002年Muyard等从分布于澳大利亚东南部和新西兰北部的植物Phebalium clavatum中分离出来的八个3位具有异戊烯基结构的天然产物[2],其合成尚未见文献报道.我们小组在对香豆素合成研究的基础上,以2,4-二羟基苯甲醛为原料,高温关环、末端双键氧化成醛等为关键步骤,高产率、高立体选择性地合成了Phebaclavin C(1),从而探索出一条简便、实用的合成该类化合物的通用方法.1的谱图数据与文献报道一致,其它化合物的合成正在进行之中.     

Brefeldin A全合成研究新进展

Brefeldin A(布雷菲德菌素甲)是一种天然抗生素, 最早发现于1958年, 许多种微生物中都能产生该化合物. 由于其有趣的结构和显著的抗真菌、抗病毒、抗肿瘤等生物活性, 该化合物很早就引起合成化学家们的注意. 到目前为止, 文献中有报道的全合成和表观合成已有30多种. 对近十年来的全合成及部分表观合成进行了综述, 对各路线的主要优缺点也进行了简要的分析. 一些类似物的合成也一并予以简介.     

Studies Towards the Total Synthesis of Methyl Isosartortuoate： The Synthesis of a Cyclic Precusor of the Diene Unit

The preparation of the key intermediate 4 of the methyl isosartortuoate is described. The macrocyclization was completed through an intramolecular [ 2,3]-Wittig ring contraction. The four necessary stereogenic carbons were established by Sharpless asymmetric AE and AD reaction.     

Facile Synthesis of Ophipogonin C＇ and its Three Analogues

Three natural diosgenyl glycosides： Ophipogonin C （A）, Polyphillin C （B）, diosgenyl α-L-rhamnopyranosyl-（1→4）-β-D-glucopyranoside （DRG） （C） and one of their analogue diosgenyl α-L-rhamnopyranosyl-（1→6）-β-D-glucopyranoside （D） were first systemic synthesized in a facile way in high yields.     

Lycogarubin C和Lycogalic Acid A的全合成

Lycogarubin C和Lycogalic acid A是用于研究DNA拓扑异构酶I(Topo I)抑制剂的重要海洋天然产物.我们以叔丁基二甲硅基(TBS)保护的3-丁炔-1醇为起始原料,以二甲基1,2,4,5-四嗪-3,6-二羧酸酯与炔的杂/逆Diels-Alder反应为关键反应,经1,2-二嗪还原,Swern氧化,Fischer吲哚合成等八步反应实现了Lycogarubin C的全合成,再将Lycogarubin C以氢氧化钾处理得到Lycogalic acid A.     

氮杂Wittig反应的最近进展

综述了最近几年氮杂Wittig反应的研究进展,包括分子间氮杂Wittig反应、分子内氮杂wittig反应及串联的氮杂Wittig反应。讨论了氮杂Wittig反应在一些含氮杂环、稠杂环及天然产物合成中的应用。     

具有氟烷基边链和手性中心液晶化合物的合成及液晶性研究

本文设计合成了十个含氟烷基边链和手性中心的液晶化合物，并通过DSC和偏光显微镜对它们的液晶性进行了研究。其中二环系液晶化合物不显示液晶相或仅显示单边近晶A相。三环系液晶化合物中较长的氟烷基边链有利于近晶相的形成，且当液晶核另一端的烷氧基链的长度适中时，在氟烷基边链和液晶核之间具有手性中心的液晶分子显示了手性近晶C相和其它液晶相。     

Studies on the Synthesis of Penazetidine A, an Alkaloid Inhibitor of Protein Kinase C

A convergent asymmetric synthesis of (2S, 3R, 4S, 12′R)-3-hydroxy-2-hydroxymethyl-4-(12′-methyloctadecyl)-N-（p-tolylsulfonyl)-azetidine, a key precursor of penazetidine A, has been achieved by starting from divinylcarbinol.     

Synthesis of a New Cerebroside Isolated from Typhonium giganteum Engl

The stereoselecfive synthesis of typhoniside, a new cerebroside isolated from Typhonium giganteum Engl. was accomplished.Cerebrosides are a kind of glycolipids highly enriched on the surface of myelin-producing cells and are composed by C18-4,8-sphingadienine, a-hydroxy acid and a saccharide head. It was the first time that cerebrosides were isolated from this traditional Chinese medicine (TCM) by us. In this paper, C18-4,8-sphingadienine was synthesized from D-xylose via a SN2 type reaction, α-Hydroxy acid was prepared from (R)-4-hydroxyte-trahydrofuran-2-one, which in turn could be obtained from Lascorbic acid.     

仙茅素A的全合成

首次报道了仙茅素A[2,5-双(3,4-二羟基苯基)呋喃-3-甲醛]的全合成。以3,4-二甲氧基苯乙酮为起始原料,经Paal-Knorr反应,选择性溴代及还原等反应合成了仙茅素A,其结构经1H NMR,13C NMR和ESI-MS表征。     

First Total Synthesis of Bauerine C

The first total synthesis of Bauerine C, a unique indoloquinazoline alkoloid, has been achieved from readily available 2,3‐dichloroaniline. The key step is the Japp–Klingmann condensation between 2,3‐dichloroaniline and ethyl‐2‐acetyl‐5‐phthalimido pentanoate to get 3‐[(2,3‐dichlorophenyl)‐hydrozono]‐pipiridin‐2‐one, which cyclizes to 7,8‐dichloro‐2,3,4,9‐tetrahydro‐β‐carbolin‐1‐one, which can be methylated by dimethyl sulphate to give 7,8‐dichloro‐9‐methyl 2,3,4,9‐tetrahydro‐β‐carbolin‐1‐one. This N‐methyl derivative is then subjected to dehydrogenation with 2,3‐dichloro‐5,6‐dicayano‐1,4‐benzoquinone (DDQ) to give the target compound Bauerine C.     

Phebalosin的全合成

以间苯二酚和D,L-苹果酸为原料,经Pechmann反应、Reimer-Tiemann反应、Darzens缩合反应及Wittig反应合成了Phebalosin,总收率1.3%,其结构经~1H NMR和~(13)C NMR表征.     

Toward the Total Synthesis of Scleritodermin A: Preparation of the C(1)-N(15) Fragment

The synthesis of the C₁-N₁₅ fragment of the marine natural product Scleritodermin A has been accomplished through a short and stereocontrolled sequence. Highlights of this route include the synthesis of the novel ACT fragment and the formation of the α-keto amide linkage by the use of a highly activated α,β-ketonitrile.     

New Concise and Efficient Synthesis of Rubrolides C and E via Intramolecular Wittig Reaction

A short total synthesis of rubrolides C and E has been achieved in four steps, using readily available 4‐methoxyacetophenone, 2‐bromoacetic acid, and the appropriate aromatic aldehyde, in 46 and 45% yield, respectively. Key reactions involved are α‐tosyloxylation of the aryl methyl ketone, intramolecular Wittig reaction, Knoevenagel condensation, and demethylation.     

First Total Synthesis of Hyacinthacine A6 from the Protected Derivative of Polyhydroxylated Pyrrolidine

（1S、2R、3R、5R、7aR）-1,2-Dihydroxy-3-hydroxy methyl-5-methylpyrrolizidine（hyacinthacine A6, I） was synthesized by Wittig＇s methodology via the reaction of aldehyde 6, prepared from the partially protected derivative of polyhydroxylated pyrrolidine, with appropriated ylides, followed by cyclization through the intemal reductive amination process of the resulting a,B-unsaturated ketone 7, and total deprotection.     

Intramolecular Wittig Reaction: A New Synthesis of (S)‐Pyrrolam A

A straightforward synthesis of (S)‐pyrrolam A is described. The synthesis involves in situ generation of the phosphorane 3 , followed by an intramolecular Wittig reaction to furnish (S)‐pyrrolam A.