Substituent effect investigation of 3-(2, 4-dichlorophenyl)-1-(4′-X-phenyl)-2-propen-1-one. Part 1. Correlation analysis of 13C NMR chemical shifts
作者:A. Perjéssy、H. K. Al-Amood、G. F. Fadhil、N. Prónayová
DOI:10.1002/poc.1718
日期:2011.2
significant correlation for CO and C‐6 13CNMR CS. MSP of σq and DSP of Taft and Reynolds models significantly correlated 13CNMR CS of Cβ. MSP of σq fails to correlate C‐1′ 13CNMR CS. Investigation of 13CNMR CS of non‐chlorinated chalcones series: 3‐phenyl‐1‐(4′‐X‐phenyl)‐2‐propen‐1‐one has revealed similar trends of substituent effects as in the chlorinated chalcones series for C‐1′, CO, Cα, and
合成了一系列取代的氯代查耳酮,即3-(2,4-二氯苯基)-1-(4'-X-苯基)-2-丙-1-酮,X为H,NH 2,OMe, Me,F,Cl,CO 2 Et,CN和NO 2。13 C NMR化学位移(CS)的双取代基参数(DSP)模型表明,π极化概念可用于解释CO的反向场效应,CO,C-2和C-的增强的取代基场效应5,C-6处取代基场效应的灵敏度降低。亚苄基环上的氯原子偶极方向会根据其与探针位点上的取代偶极偶合的方式来增强或降低取代基效果。的相关13C-2,C-5和C-6的σ和σ的C NMR CS表明,亚苄基环中的氯原子会耗尽电荷。Hammett的MSP和Taft 13 C NMR CS模型的DSP都在C-2,C-5和C-6处给出相似的取代基效应趋势。但是,前者未能对CO和C-6 13 C NMR CS给出显着的相关性。的MSP σ q和和塔夫脱的DSP雷诺数模型显著相关13的C C NMR
Uncatalyzed conjugate addition of organozinc halides to enones in DME: a combined experimental/computational study on the role of the solvent and the reaction mechanism
calculations, prompted by the experimental aggregation study, revealed an unexpected reactionmechanism, where the coordinating capabilities of DME stabilize a transition state involving two organozinc moieties, lowering the activation energy of the reaction with respect to that seen for THF, enough to explain the fast and quantitative reactions observed experimentally and the different behaviors of
A simple organocatalytic Michael-aldol-dehydration domino approach to chiral 3,5-diaryl-cyclohexenones from acetone and α,β-unsaturated ketones was developed for the first time using a simple chiral primary amine as a catalyst. Moderate to good yields (up to 85%) and excellent enantioselectivities (88–98% ee) were obtained.
Design and synthesis of novel natural clinoptilolite-MnFe2O4 nanocomposites and their catalytic application in the facile and efficient synthesis of chalcone derivatives through Claisen-Schmidt reaction
the aldol-type Claisen–Schmidt reaction for the synthesis of chalcones. A strong catalytic synergy was observed between nano-MnFe2O4 particles and natural clinoptilolite in the structure of these nanocomposites. The products with a broad range of substituents on the reactants were efficiently obtained under room-temperature conditions within relatively short reaction times with good to excellent yields
通过使用各种量的锰铁氧体(MnFe 2 O 4)纳米粒子修饰天然斜发沸石的表面,制备了一系列三种新型纳米复合材料。通过XRD,FT-IR,EDX,VSM和TEM分析,可以充分表征这些锰铁氧体改性的纳米复合材料(MFO-NC)。在斜发沸石(MFO–NC-3)中含有40 wt%锰铁氧体的这些新型纳米复合材料之一在醛醇型Claisen–Schmidt反应中显示了强大的催化行为,可合成查耳酮。在纳米MnFe 2 O 4之间观察到强烈的催化协同作用这些纳米复合材料的结构中存在颗粒和天然斜发沸石。在一种制备的MFO-NC纳米复合材料的存在下,在室温条件下,在较短的反应时间内即可有效地获得在反应物上具有广泛取代基的产物,并具有良好或优异的收率。这种纳米复合材料在查耳酮的合成中也显示出很强的稳定性和可重复使用性。
Catalyst-free chemoselective conjugate addition and reduction of α,β-unsaturated carbonyl compounds <i>via</i> a controllable boration/protodeboronation cascade pathway
作者:Xi Huang、Junjie Hu、Mengying Wu、Jiayi Wang、Yanqing Peng、Gonghua Song
DOI:10.1039/c7gc02863f
日期:——
addition and 1,4-reduction of α,β-unsaturatedcarbonylcompounds. Without any metal-catalyst or base, a series of β-boration products of α,β-unsaturatedcarbonylcompounds was easily obtained in moderate to excellent yields in a mixed solvent of ethanol and water. The presence of a catalytic amount of Cs2CO3 can effectively induce further protodeboronation reaction towards 1,4-reduction products at
已开发出一种新颖,有效的无过渡金属且可控制的硼酸化/原硼酸脱硼策略,用于化学选择性结合物的添加和α,β-不饱和羰基化合物的1,4-还原。在没有任何金属催化剂或碱的情况下,在乙醇和水的混合溶剂中,很容易以中等至极好的收率获得一系列α,β-不饱和羰基化合物的β-硼酸酯产物。催化量的Cs 2 CO 3的存在可以在较高的反应温度下有效地引发进一步的原硼酸脱硼反应,生成1,4-还原产物。因此,通过稍微改变反应条件,可控制地获得α,β-不饱和羰基化合物的硼酸化或还原产物。机理研究表明Cs 2CO 3在激活原去硼化步骤中起关键作用。这种无过渡金属催化剂且产物可控的方法为高化学选择性制备α,β-不饱和羰基化合物的β-硼酸酯产物和1,4-还原产物提供了有用且环保的工具。