3-甲基-5-苯砜基-3E-戊烯-1-醇的立体专一性合成

3-甲基-5-苯砜基-3E-戊烯-1-醇(1)是合成某些萜类化合物的重要中间体.它具有反式烯丙基苯砜基双键.Julia等曾报道用含砜基的环丙基醇的开环重排反应来实现这类化合物的立体选择性合成,但其开环前体不易得到.本文以4-羟基-2-丁酮(2)为起始原料,经4步反应立体专一性地合成了标题化合物1.合成路线短、操作简便、易于大量制备.合成路线用方程式表示如下:     

从中国南海软珊瑚中分离的环氧西松烯天然产物的结构更正

(- ) - 7,8- Epoxycembrene- C[( - ) - 7,8- ECC,1 ]是 Bowden等 [1] 于 1 980年首次从澳大利亚软珊瑚Sarcophyton crassocaule中分离得到的新的环氧西松烯 .其化学结构经光谱数据证实为 ( 1 E,3E,1 1 E) -1 -异丙基 - 4,8,1 2 -三甲基 - 7,8-环氧 - 1 ,3,1 1 -十四碳环三烯 ,但 C- 7,C- 8位环氧的立体化学未被确定 . Shin等 [2 ] 也从未鉴定属名的加勒比海域的软珊瑚 Eunicea sp.中分离得到过该天然产物 . 1 997年 ,饶志刚等 [3] 报道了从中国南海肉芝软珊瑚 ( Sarcophyton molle)中分离得到一环氧西松烯天然产物 ,确定其结构为天然…     

Studies on Macrocyclic Diterpenoids (Ⅵ)——A Novel Synthetic Route to (±)-Cembrene-A

The total synthesis of(土)-cembrene-A, a termite pheromone, was achieved from geranylacetone and geraniol as starting materials. The key steps were the phase transfer catalyzed coupling reaction of sulphone (6) with chloride (9) and the intramolecular macrocyclization of dicarbonyl precursor (12) induced by low valent titanium. The synthetic route was short with anoverall yield of 17%.     

利用BESⅢ的双层TOF寻找D0-D0混合的研究

在ψ(3770)处, D⁰→K^－π⁺是研究D⁰-D⁰混合的非常理想的衰变道. 实验上, 良好K/π识别技术将对寻找D⁰-D⁰混合过程起着决定性的作用. 在BESⅢ实验的物理预研究中, 发现利用飞行时间的信息, 能够精确测定末态中含有多条带电径迹事例的起始时间, 从而可以改善飞行时间计数器的时间分辨率. 进一步的研究表明, 应用该方法后, BESⅢ双层TOF的时间分辨率从～78ps降到～64ps. 按照20fb^－1的ψ(3770)数据量进行估算, 在95%置信度下, D⁰-D⁰混合率的上限值可以提高7%左右.     

Time calibration for the end cap TOF system of BESⅢ

The time calibration for end cap TOF system of BESⅢ is studied in this paper. It has achieved about 110 ps time resolution for muons in dimu events. The pulse height correction using electronic scan curve and the predicted time calculated using Kalman filter method are introduced. This paper also describes the study of using electrons and muons as calibration samples.     

The First Synthesis of Ethyl 3,7,11,15-Tetramethyl-14-oxo-15-tert-butyldimethylsiloxy-2E,6E,10E-hexadecatrienoate——The Key Precursor of 2-Hydroxynephthenol

以香叶基丙酮为起始原料，经五步反应以３２％的总收率首次合成了３，７，１１，１５－四甲基－１４－氧代－１５－叔丁基二甲基硅氧基－２Ｅ，６Ｅ，１０Ｅ－十六碳三烯酸乙酯。它是２－Ｈｙｄｒｏｘｙｎｅｐｈｔｈｅｎｏｌ全合成中的酮酯关环前体。     

分子内相互作用的认知: 二茂铁共轭联多吡啶配体及其配合物的结构及性质

报道了６－二茂铁基－２，２－联吡啶（ｆｃｂｐｙ）配体和４－二茂铁基－２，２，６，２″－联三吡啶（ｆｃｔｐｙ））的Ｍｎ（Ｉ）配合物１（［Ｍｎ（ＩＩ）（ｆｃｔｐｙ）２］（ＣｌＯ４）２·２Ｈ２Ｏ）的晶体结构．电化学研究结果显示：联多吡啶取代基的吸电子诱导效应使二茂铁部分的氧化电位发生了明显的正移．而配体ｆｃｔｐｙ与其配合物１的结构比较表明：Ｍｎ（Ｉ）离子的引入对配体部分的键长却没有明显影响     

The effect of electron initial longitudinal velocity on non-sequential double ionization process in elliptically polarized laser field

The effect of initial longitudinal velocity of the tunnelled electron on the non-sequential double ionization (NSDI) process in elliptically polarized laser field is studied by a semiclassical model. We find that the non-zero initial longitudinal velocity has a suppressing effect on single-return collision (SRC) events in double ionization process, more specifically, it results in an obvious reduction in the center part of the correlation momentum distributions in the direction of the major polarization axis (z axis) and makes the distribution of single-return collision in the minor polarization axis (x axis) become narrow.