一个8-O-4'新木脂素化合物的对映选择性合成

报道了一条立体选择性合成赤式8-O-4'新木脂素的新路线. 以Sharpless双羟化反应构筑2个手性中心, 经过几步转化, 得到关键中间体6, 通过Mitsunobu反应进行偶联, 可以得到单一赤式的8-O-4'新木脂素化合物. 通过此路线, 立体选择性地合成了一个天然8-O-4'新木脂素的赤式异构体.     

倍半木脂素threo-(±)-3,4-二香草基四氢呋喃阿魏酸酯的全合成

报道了一条合成天然产物3,4-二香草基四氢呋喃阿魏酸酯的方法.以香草醛为原料,经过两步Stobbe反应构建木脂素骨架,然后再加氢、LiAlH4还原,产物经柱层析分离后得到两个异构体meso-和threo-(±)-开环落叶松脂素;它们分别与TsCl作用,发生分子内反应得到关键的四氢呋喃木脂素中间体meso-和threo-(±)-shonanin;最后,分别与MOM保护的阿魏酸缩合得到倍半木脂素threo-(±)-3,4-二香草基四氢呋喃阿魏酸酯和衍生物erythro-(±)-3,4-二香草基四氢呋喃阿魏酸酯.合成采用汇聚法,经13步,以约8%～9%的总产率得到了目标产物.     

一个8-O-4′新木脂素化合物的对映选择性合成

报道了一条立体选择性合成赤式8-O-4′新木脂索的新路线，以Sharpless双羟化反应构筑2个手性中心，经过几步转化，得到关键中间体6，通过Mitsunobu反应进行偶联，可以得到单一赤式的8-O-4′新木脂索化合物．通过此路线，立体选择性地合成了一个天然8-O-4′新木脂素的赤式异构体。     

Threo-(±)-开环异落叶松脂醇二阿魏酸酯的全合成

报道了双木脂素threo-(±)-开环异落叶松脂醇二阿魏酸酯的全合成.以香草醛为原料,经过两步Sto-bbe反应构建木脂素骨架,然后再用LiAlH4还原、加氢后,产物经柱层析分离,得到2个异构体meso-和threo-(±)-开环落叶松脂素;根据其NMR,IR和HRMS等谱图确认发现,极性较小的产物threo-(±)-开环落叶松脂素为合成的关键中间体.threo-(±)-开环落叶松脂素与甲氧甲基(MOM)保护的阿魏酸缩合得到目标产物threo-(±)-开环异落叶松脂醇二阿魏酸酯.合成采用汇聚法,经11步,以约8%的总产率得到了目标产物.该合成方法具有原料价廉易得及操作简便的优点,并具有一定的实用价值.     

丁烷型木脂素及衍生物的合成和生物活性

报道了一条合成丁烷木脂素的新路线. 以芳香醛为起始原料, Stobbe缩合和烷基化反应为关键步骤, 构建了木脂素骨架, 再经拆分及还原, 可得到相应的苏式和赤式异构体. 经官能团转化得到5个丁烷木脂素和8个丁醚木脂素, 其中3个天然产物为首次合成. 对合成产物进行抗HIV病毒和和抗疱疹病毒活性研究, 部分化合物显示出较高的抗病毒活性, 而且骨架构型对活性影响较大.     

Threo-(±)-开环异落叶松脂醇二阿魏酸酯的全合成

报道了双木脂素threo-(±)-开环异落叶松脂醇二阿魏酸酯的全合成. 以香草醛为原料, 经过两步Stobbe反应构建木脂素骨架, 然后再用LiAlH₄还原、加氢后, 产物经柱层析分离, 得到2个异构体meso-和threo-(±)-开环落叶松脂素; 根据其NMR, IR和HRMS等谱图确认发现, 极性较小的产物threo-(±)-开环落叶松脂素为合成的关键中间体. threo-(±)-开环落叶松脂素与甲氧甲基(MOM)保护的阿魏酸缩合得到目标产物threo-(±)-开环异落叶松脂醇二阿魏酸酯. 合成采用汇聚法, 经11步, 以约8%的总产率得到了目标产物. 该合成方法具有原料价廉易得及操作简便的优点, 并具有一定的实用价值.     

(2R，3R)-和(2S，3S)-2-(4-羟基-3-甲氧基)-3-羟甲基-1，4-苯并二氧六环-6-醛的对映选择性合成

1,4-苯并二氧六环木脂素类天然产物多数具有增加胆碱乙酰化酶和抗肝毒等活性 ,其活性主要源于 1 ,4-苯并二氧六环官能团 [1] . 1 ,4-苯并二氧六环木脂素的消旋全合成已有报道 [2 ] ,但其不对称合成还是空白[3] .我们发展了一条对映选择性合成 1 ,4-苯并二氧六环木脂素的简捷有效的路线 .基于前面的工作 [4 ] ,我们发现 1 ,4-苯并二氧六环醛类衍生物是合成此类天然产物的关键中间体 ,选择 2 - (4-羟基- 3-甲氧基 ) - 3-羟甲基 - 1 ,4-苯并二氧六环 - 6-醛 (1 )作为目标分子 ,其合成路线如下 :Reagents and conditions:( ) Me OH,H2 SO4,9…     

新型含1,2,3-三氮唑的染料木素糖缀合物的合成

以染料木素为起始原料,经两步反应制得中间体7-O-炔丙基染料木素(3);以CuI为催化剂,3与叠氮乙酰基糖经Click反应合成了7-O-［1-(2,3,4,6-四-O-乙酰基-β-D-糖苷)1H-1,2,3-三氮唑-4-甲基］-染料木素(5a~5c); 5a~5c经去乙酰基制得三种含1,2,3-三氮唑的氮苷染料木素糖缀合物(6a~6c)。3, 5和6均为新化合物,其结构经¹H NMR, ¹³C NMR和HR-MS表征。     

异维A酸新木脂素酯的合成与表征

以香草醛(或对羟基苯甲醛)和丙二酸为原料,经Knoevenagel反应、酯化、氧化银为氧化剂的自由基仿生氧化偶联反应合成了新木脂素3a,3b。3a,3b分别与异维A酸酯化,合成了两种新型的异维A酸新木脂素酯4a和4b。用1H NMR,IR和MS对它们的结构进行了表征。研究了异维A酸酯的反应机理。     

(±)-Sinaiticin的首次全合成

首次完成了黄酮木脂素 (± ) -Sinaiticin的全合成 ,通过 9步反应 ,总产率为 1 3.4% ,cis-6发生差向异构化转化为 trans-7,氧化偶联为关键步骤 .     

(R)-2-{[4-(3-甲氧基丙氧基)-3-甲基吡啶-2-基]甲基亚硫酰基}- 1H-苯并咪唑的合成

以2,3-二甲基吡啶为起始原料, 经过11步反应, 不对称合成了质子泵抑制剂的关键中间体: (R)-2-{[4-(3-甲氧基丙氧基)-3-甲基吡啶-2-基]甲基亚硫酰基}-1H-苯并咪唑. 研究了用手性高效液相色谱拆分对映体、测定产品光学纯度的方法, 结果表明目标产品的ee值达到99%. 通过IR, UV, MS以及1H NMR分析对重要中间体和目标产品进行了结构鉴定.     

硼氢化钠还原法合成1-(2,4-二氯苯基)-2-氯-乙醇

研究了硼氢化钠还原2,2',4'-三氯苯乙酮制备1-(2,4-二氯苯基)-2-氯-乙醇的两种方法. 考察了温度对反应的影响, 对目标产物和副产物的生成机理进行了探讨. 加入氯化钙、氯化镧等金属氯化物能有效促进反应的专一性, 并对其作用机理进行了探讨. 在非质子溶剂如THF中有阳离子树脂的存在下, 还原反应平稳, 具有高产率和高选择性. 对目标产物进行了结构表征.     

4-(3,4-二氯苯基)-1-萘满酮的合成

以1-萘酚和邻二氯苯为原料,无水三氯化铝为催化剂,经一步Friedel- Crafts反应合成了抗抑郁药盐酸舍曲林的重要中间体4-(3,4-二氯苯基)-1-萘满酮,通过探讨其反应机理优化了合成条件,并采用高效液相色谱,红外光谱,核磁共振和元素分析等手段确认了产物结构。经改进后的合成产率达72.8%。     

Total synthesis of (-)-8-O-methyltetrangomycin (MM 47755)

A stereoselective total synthesis of the natural antibiotic (-)-8-O-methyltetrangomycin 1 is reported. The essential steps for this convergent synthesis are the transformation of a geraniol epoxide into a chiral octadiyne derivative, which was converted into a triyne. The cobalt-mediated [2+2+2] cycloaddition of the triyne led to a benz[a]anthracene system, which was oxidized with Ag(Py)(2)MnO(4) to a benz[a]anthraquinone. Deprotection with aqueous HF in acetonitrile and photooxidation afforded the desired product (-)-1. [reaction: see text]     

Total synthesis of the marine alkaloid (-)-lepadin B

An enantioselective total synthesis of (-)-lepadin B has been developed starting from (2S,4S)-2,4-O-benzylidene-2, 4-dihydroxybutanal. The key steps in the synthesis include the use of an aqueous intramolecular acylnitroso Diels-Alder reaction to afford the trans-1,2-oxazinolactam and Suzuki cross-coupling reaction to elaborate the (E,E)-octadienyl unit.     

Stereoselective synthesis of (-)-4-epiaxinyssamine

The synthetic studies towards axinyssamine, a cytotoxic and coral-lethal compound isolated from the Caribbean sponge Axinyssa ambrosia were performed. The Ritter reaction on the key intermediate with chloroacetonitrile, resulted in the introduction of the amino group at C-4 generating the configuration of this stereocentre opposite to that of the natural product. As a result, the first total synthesis of the unnatural (-)-4-epiaxinyssamine was achieved.     

A second generation formal synthesis of (-)-cephalotaxine

A second generation formal synthesis of the alkaloid (-)-cephalotaxine has been achieved using an alkylidene carbene 1,5-CH insertion reaction to establish a key quaternary stereocenter. The carbene precursor was readily derived from L-proline, and the 1,5-CH insertion reaction was performed under Ohira's conditions using lithiotrimethylsilyldiazomethane (LTDM), which gave the desired spirocyclic product in 74% yield. The hydroxymethyl group was then oxidized and then decarbonylated (93%), and this material was easily transformed into the desired Friedel-Crafts cyclization precursor. Exposure of this material to SnCl4 then gave the desired pentacyclic product, which was identical to that previously prepared by Mori and thus represents a formal total synthesis of (-)-cephalotaxine.     

A straightforward synthesis of (-)-phaseolinic acid

A concise approach to (-)-phaseolinic acid starting from commercially available (S)-oct-1-yn-3-ol is disclosed. The key steps are a ring-closing metathesis reaction to prepare a C(2)-symmetrical allylic diol and its desymmetrization to a gamma-butyrolactone by using an Ireland-Claisen rearrangement. The 2S,3S,4S configuration of the levogyre natural product has been confirmed.     

Total synthesis of (-)-xyloketal A

[reaction: see text] The first total synthesis of the C(3)-symmetric and biologically active natural product, (-)-xyloketal A, has been accomplished in one step from phloroglucinol (1,3,5-trihydroxybenzene) and (4R)-3-hydroxymethyl-2,4-dimethyl-4,5-dihydrofuran. This remarkably direct process involved an exceedingly facile and diastereoselective boron trifluoride diethyl etherate-promoted triple electrophilic aromatic substitution reaction that was coupled to three bicyclic acetal formation reactions.     

Synthesis of [ethylene-1-(eta(5)-4,5,6,7-tetrahydro-1-indenyl)-2- (eta(5)-4',5',6',7'-tetrahydro-2'-indenyl)]titanium dichloride, the elusive isomer of the Brintzinger-type ansa-titanocenes

We present a short synthesis of 1-(2-indenyl)-2-(3-indenyl)ethane (5) and a method for its conversion to the ansa-metallocene [ethylene(eta5-inden-1-yl)(eta5-inden-2-yl)]titanium dichloride (13). The synthetic strategy applied to prepare bisindene 5 relies on the efficient alkylation of 2-(phenylsulfonyl)indane followed by HMPA-assisted E1cB-elimination of phenylsulfinate. This tandem sequence circumvents the predisposition of indene to undergo C(1)-alkylation and enables access to C(2)-substituted indenes. The key step in the synthesis of the title ansa-titanocene (4) features a previously unreported equilibration step to generate the bis(indenide anion) of 5. Complexation with TiCl4.(THF)2 followed by hydrogenation of the product metallocene furnishes ansa-titanocene 4.