叔醇的动力学拆分研究进展

手性叔醇结构广泛存在于生物活性物质、天然产物和药物分子中,实现其高效不对称催化合成具有重要意义.消旋醇的动力学拆分是一种合成高光学纯度手性醇的重要方法,然而由于叔醇α-碳上带三个不同的非氢取代基团,手性识别难度较大,因而发展高效且具有广泛底物适用性的叔醇动力学拆分方法具有较大的挑战.尽管如此,近年来非酶催化的叔醇的动力学拆分领域取得了快速的发展,一些新颖的不对称催化反应、催化体系被成功应用于叔醇的动力学拆分反应中.对叔醇动力学拆分反应进行了系统总结,分类介绍了这些反应的底物适用性、特点、机理以及局限等,并对该领域的未来发展进行展望.     

从叔醇制备叔硫醇

实验室中合成叔硫醇缺少简便方法。用叔醇和氢溴酸与硫脲直接反应是目前采用的方法。Lee和Akerstrom曾用此法合成了叔硫醇,但碳原子数没超过七个。Sprague及Kresze分别用干燥氯化氢及盐酸代替氢溴酸也合成了叔硫醇,但产率不高。本文提出了用叔醇、硫酸与硫脲反应来制备叔硫醇的方法,并合成了六个叔硫醇。     

铜/钯共催化的烯烃不对称硼碳化反应

正手性有机硼化合物是重要的构建碳-碳键和碳-杂键的合成子,被广泛应用于天然产物、生物活性小分子及功能材料的合成中.通过烯烃不对称硼碳化反应来构建手性有机硼化合物是一种简洁高效的方法,目前相关报道非常少.中国科学院成都生物研究所廖建课题组利用铜/钯双金属共催化(串联)策略,首次实现了联硼酸频哪醇酯和烯丙基叔     

水相催化3,5-二烷基-4-硝基异噁唑与三氟甲基酮的亲核加成反应（英文）

研究了水相三乙胺催化3,5-二烷基-4-硝基异噁唑与三氟甲基酮的亲核加成反应,以66%~99%的产率合成了一系列三氟甲基叔醇衍生物.通过脱水或氧化反应可有效的将目标产物转化为烯烃或羧酸类化合物.     

4－叔丁基－β－氯－α－甲基肉桂醛的合成

从苯和叔了醇出发，经过３步反应合成得标题化合物，总收率在６８％以上。     

一个新颖南极微生物酯酶EST112-2的功能鉴定和在手性叔醇(S)-芳樟醇制备中的应用（英文）

手性叔醇是合成药物和一些香料产品的非常重要中间体.芳樟醇是叔醇的一种,不同构型的芳樟醇具有不同的香气.因此如何研发合适的制备方法以获得高光学纯度的芳樟醇等叔醇是急需解决的技术问题.生物酶催化合成符合绿色化学的理念,但是由于叔醇化学结构中的空间位阻影响,使用生物酶催化的拆分反应制备高光学纯度的叔醇比较困难.对来自南极微生物的一个新的酯酶EST112-2进行了功能鉴定,并将其作为合成手性芳樟醇的生物催化剂.EST112-2可以通过不对称水解乙酸芳樟酯获得(S)-芳樟醇.对反应的p H、温度、共溶剂、底物浓度、催化剂用量以及反应时间等参数进行优化,EST112-2制备的(S)-芳樟醇的光学纯度大于66%,得率超过72%.EST112-2制备的(S)-芳樟醇的光学纯度要远远高于以往报道.     

苹果蠹蛾性信息素的合成研究进展

综述了用Wittig反应构建烯烃、炔化物还原、烯烃硼氢化、山梨酸衍生物格氏偶联、油脂的氧化-还原等方法,合成苹果蠹蛾性信息素(8E,10E-十二碳二烯-l-醇)的研究进展。并介绍了其部分类似物的合成方法。参考文献21篇。     

叔膦促进下两种亲电试剂之间的环化反应研究进展

发展环状化合物的高效合成方法对药物分子、天然产物及其他功能有机分子的合成具有重要意义.近年来,叔膦促进下两种亲电试剂之间的环化反应,由于具有原料简单易得、反应条件温和、且无需金属参与等优点,同时为多种碳环及杂环化合物的合成提供了高效的新途径,因而受到了合成化学家的广泛关注.这类反应通常经过叔膦对亲电试剂进行亲核加成,产生两性离子活性中间体这一关键步骤来完成.根据两性离子的不同来源,综述了叔膦促进下缺电子联烯、Morita-Baylis-Hillman烯丙基化合物、缺电子烯烃与其他亲电试剂之间的环化反应.     

催化,C_1化学与低碳醇的制取

一、引言以现代催化理论为基础研究合成气化学与甲醇化学,在两次世界性能源危机急迫感的推动下,有了飞速的发展。以一氧化碳加氢合成油品、低碳烯烃及低碳醇,以甲醇为基础原料合成油品、低碳烯烃及同系醇,成为引人关注的课题。这些反应能否带来工业化的前景,在原料     

α-烯烃不对称羰基化反应研究最新进展

自1938年Roelent引发现首例烯烃羰基化反应以来,以一氧化碳为原料,经催化合成含氧有机化合物的羰基化过程,已经成为化工生产和科学研究中广泛采用的非常简便的合成方法．除烯烃外,炔烃、醇、卤代烃、醚等均能作为羰化反应的底物,生成的醛、酯、羧酸、酰胺等产物可以为医药、     

A Facile Conversion of Tertiary Alcohols to Olefins

An efficient method for the dehydration of tertiary alcohols to obtain olefins in high yield, employing methanesulfonyl chloride-triethylamine and catalytic amount of 4-dimethylaminopyridine in dichloromethane, is described.     

三级醇的脱水及C-乙酰化反应

冰乙酸—乙酸酐—高氯酸体系通常用作醇的快速乙酰化,也曾用于醇的脱水反应,但我们发现三级醇类化合物在上述体系中可以形成双键的乙酰化产物,收率颇高,因此,我们做了一些探索。     

Dehydration of alcohols catalyzed by copper(II) sulfate adsorbed on silica gel

Copper(II) sulfate adsorbed on silica gel efficiently dehydrated secondary and tertiary alcohols under mild conditions to give olefins. The rate of dehydration of tertiary alcohols is much faster than that of secondary alcohols.     

Regioselective dehydration of axial and equatorial tertiary alcohols with α-methyl group in the cyclohexane ring by Swern’s reagent

Swern’s reagent (a complex of oxalyl chloride with DMSO) was shown to dehydrate tertiary alcohols containing an α-methyl group in the cyclohexane ring. Dehydration of equatorial alcohols affords mixtures of isomeric compounds where isomers with an exocyclic double bond dominate, whereas isomers with an endocyclic double bond prevail in the products of dehydration of axial tertiary alcohols. Thus, Swern’s reagent can serve as a chemical test to determine the configuration of tertiary alcohols containing an α-methyl group in cyclohexane ring. The composition of the products of dehydration of these alcohols with Swern’s reagent is similar to that obtained by their dehydration with POCl₃ in pyridine. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 800–803, April, 1997.     

Synthesis of Benzyl Alkyl Ethers by Intermolecular Dehydration of Benzyl Alcohol with Aliphatic Alcohols under the Effect of Copper Containing Catalysts

Synthesis of benzyl alkyl ethers was performed in high yields by intermolecular dehydration of benzyl and primary, secondary, tertiary alcohols under the effect of copper containing catalysts. The formation of benzyl alkyl ethers occurs with participation of benzyl cation.     

Synthesis of 3‐Butadienyl‐1‐tosylpyrroles

A pathway for the formation of 3‐butadienyl‐1‐tosylpyrroles from 3‐acyl derivatives via secondary and tertiary 3‐hydroxyalkyl‐1‐tosylpyrroles has been developed. The dehydration of the alcohols intermediates is the crucial step: conditions for high chemo‐ and diastereocontrol are described.     

A facile method for the rapid and selective deprotection of methoxymethyl (MOM) ethers

We describe a rapid and efficient method for selective deprotection of methoxymethyl (MOM) ethers using ZnBr₂ and n-PrSH, which completely removed MOM from diverse MOM ethers of primary, secondary, and tertiary alcohols or phenol derivatives. The deprotection takes less than ten minutes with both high yield and selectivity in the presence of other protecting groups. In addition, the rapid deprotection of MOM ethers of tertiary hydroxyls in high yield with no epimerization allows MOM to be a suitable protecting group for tertiary alcohols.     

Magnesium Bromide Catalysed Acylation of Alcohols

Magnesium bromide is an efficient catalyst for the acetylation and benzoylation of a variety of primary and secondary alcohols with the respective acid anhydrides at ambient temperature. Acetylation of tertiary alcohols requires subambient temperature to suppress competing dehydration. Coordinating solvents retard the acylation process.     

Iodine induced transformations of alcohols under solvent-free conditions

Iodine has been shown to be an efficient catalyst for transformations of alcohols under solvent-free conditions. In the presence of 5% of iodine, tertiary alcohols underwent dehydration forming the corresponding alkenes, while in the case of 2-phenylpropane-2-ol cyclodimerisation to 1,1,3-trimethyl-3-phenylindane took place. Secondary and primary benzyl alcohols under the same conditions gave the corresponding ethers.     

Amberlyst®-15: a reusable heterogeneous catalyst for the dehydration of tertiary alcohols

Tertiary alcohols react under mild conditions in the presence of Amberlyst^®-15 (dry) (solid-supported sulfonic acid) to give predominantly the most stable alkene in very good yield. The dehydration of tertiary alcohol functionality occurs without observation of rearrangement and polymerization products, and with outstanding substrate tolerance, which include the NHCBz, NHBoc, OSEM, OTBDMS, OBOM and ethylene ketal functional groups. Amberlyst^®-15 (dry) can be easily recovered from the reaction medium and reused for five cycles, maintaining the catalytic efficiency. In addition, the dehydration can occur under continuous operation.