AP 甲硅烷基膦酸酯和森田-的Baylis-希尔曼乙酸盐(MBHAs)之间C键形成反应探索作为向医药相关β-carboxyphosphinic结构基序的通用的替代方案。使用31记录的不同取代的MBHA转化为次膦酸9或14的转化率P NMR光谱显示酯和腈衍生物之间的反应性差异出乎意料。这些动力学曲线和DFT计算支持了一种机械方案,其中可以从过渡态的“迟缓”解释观察到的差异。此外,我们提供的实验证据表明,由于最初的P-Michael加成而形成的烯醇不形成。基于拟议的机械情景结合DFT计算,对E / Z的解释提出了酯和腈之间的立体选择性差异。提出了由这种转变产生的合成机会,该机会涉及几种合成的反复变化的膦基结构单元的制备,而这些结构单元通过经典的P-Michael合成路线的访问并不简单。
Probing the Mechanism of Allylic Substitution of Morita–Baylis–Hillman Acetates (MBHAs) by using the Silyl Phosphonite Paradigm: Scope and Applications of a Versatile Transformation
作者:Maria Kalyva、Alexandros L. Zografos、Era Kapourani、Evaggelos Giambazolias、Laurent Devel、Athanasios Papakyriakou、Vincent Dive、Yannis G. Lazarou、Dimitris Georgiadis
DOI:10.1002/chem.201405626
日期:2015.2.16
using 31P NMR spectroscopy revealedunexpected reactivity differences between ester and nitrile derivatives. These kinetic profiles and DFT calculations support a mechanistic scenario in which observed differences can be explained from the “lateness” of transition states. In addition, we provide experimental evidence suggesting that enolates due to initial P‐Michaeladdition are not formed. Based on
AP 甲硅烷基膦酸酯和森田-的Baylis-希尔曼乙酸盐(MBHAs)之间C键形成反应探索作为向医药相关β-carboxyphosphinic结构基序的通用的替代方案。使用31记录的不同取代的MBHA转化为次膦酸9或14的转化率P NMR光谱显示酯和腈衍生物之间的反应性差异出乎意料。这些动力学曲线和DFT计算支持了一种机械方案,其中可以从过渡态的“迟缓”解释观察到的差异。此外,我们提供的实验证据表明,由于最初的P-Michael加成而形成的烯醇不形成。基于拟议的机械情景结合DFT计算,对E / Z的解释提出了酯和腈之间的立体选择性差异。提出了由这种转变产生的合成机会,该机会涉及几种合成的反复变化的膦基结构单元的制备,而这些结构单元通过经典的P-Michael合成路线的访问并不简单。
Enzymatic process for preparing optically active 3-substituted
申请人:Fujisawa Pharmaceutical Co., Ltd.
公开号:US05241064A1
公开(公告)日:1993-08-31
Preparation of optically active 3-substituted azetidinones of the formula (I) ##STR1## in which R.sup.1 is a hydroxy-protective group wherein an allylic alcohol of the formula (II) ##STR2## is acylated, then subjected to asymmetric enzymatic hydrolysis yielding the R-allylic alcohol. The hydroxyl group is protected and then stereoselectively reacted with an amine which is subsequently cyclized to yield the desired 3-substituted azetidinone. Two new species of microorganisms have been isolated, Pimelobacter sp. No. 1254 and Bacillus megaterium No. 1253 which exhibit stereoselective esterase activity.
Esters α-méthyléniques par substitution d'éthers et d'acétates dérivés de l'α-(hydroxyméthyl)acrylate d'éthyle
作者:Hassen Amri、Monique Rambaud、Jean Villiéras
DOI:10.1016/0022-328x(90)87047-h
日期:1990.2
α-(Methylene)alkanoic esters are prepared in high yields by substitution of α-(acetoxymethyl)acrylates using Grignard reagents in the presence of a catalytic amount of copper(I) salt. This reaction can be applied to lithium enolates of esters and ketones and to give functional α-(methylene) alkanoic esters, products of great interest for the synthesis of active biological compounds (sarkomycin, α-(methylene)
Synthesis of methacrylic-type peroxidic compounds and study of their homolytic induced decomposition in solution
作者:Daniel Colombani
DOI:10.1016/s0040-4020(96)01180-5
日期:1997.2
unsaturated peroxidic compounds have been prepared, characterized and inductively decomposed in various solvents to afford the corresponding oxiranes. The reaction proceeded by a radical chain mechanism and was initiated either by thermolysis of added t-butyl peracetate at 110°C or AIBN at 80°C, or by autoxidation of BEt3 at 20°C. The studied peroxyderivatives were designed to generate oxyl radicals reacting
Divergent Amine-Catalyzed [4 + 2] Annulation of Morita–Baylis–Hillman Allylic Acetates with Electron-Deficient Alkenes
作者:Silong Xu、Rongshun Chen、Zifeng Qin、Guiping Wu、Zhengjie He
DOI:10.1021/ol2032569
日期:2012.2.17
+ 2] annulation of Morita–Baylis–Hillman allylic acetates 2 with electron-deficientalkenes or diazenes has been developed for efficient syntheses of highly functionalized cyclohexenes, tetrahydropyridazines, and important spirocycles. This reaction unveils a new reactivity pattern of the intensely studied allyliccompounds 2 acting as a C4 synthon in Lewis base catalyzed annulationreactions and also