The synthesis of 3 -aryl-N-n-propyl-piperidines is described in six steps starting from a-sulfonyl acetamide via the formal [3+3] cycloaddition reaction of the latter into glutarimide. The pathway involves an efficient cycloaddition and regioselective reduction, and yields useful building blocks for heterocyclic chemistry. (C) 2002 Elsevier Science Ltd. All rights reserved.
Highly Regioselective Friedel–Crafts Reactions of Electron-Rich Aromatic Compounds with Pyruvate Catalyzed by Lewis Acid-Base: Efficient Synthesis of Pesticide Cycloprothrin
An efficient synthesis of aromatic lactate esters is reported via highly regioselective Friedel–Crafts reactions of electron-richaromaticcompounds with pyruvate ester promoted by TiCl4 in the presence of basic Al2O3. The utility of the reaction is shown by the efficient synthesis of the pesticide cycloprothrin in high yield.
芳族乳酸酯的有效的合成报道通过用丙酮酸酯通过的TiCl促进富电子的芳族化合物的高度选择性Friedel-Crafts反应4在基本Al的存在2 Ó 3。该反应的实用性以高产率高效合成了农药环丙菊酯显示出来。
Conformational Analysis of MαNP Esters, Powerful Chiral Resolution and1H NMR Anisotropy Tools – Aromatic Geometry and Solvent Effects on Δδ Values
group, the ester carbonyl oxygen, and the methoxy oxygen supports a triangular intramolecular force to stabilize the syn-syn conformation; ii) triangular hydrogen bonding among a hydrogen atom of protic solvents, the ester carbonyl oxygen, and the methoxy oxygen also supports the syn-syn conformation. This hydrogen bonding, as the solvation effect implies, suggests that a similar hydrogen bonding between
A process for preparing a 1,2-ethanediol derivative in a high yield by reducing an α-hydroxy carboxylic acid ester derivative in a protic solvent or a hydrous aprotic polar solvent in the presence of a sodium boron hydride compound. A process for preparing a 1,2-ethanediol derivative in a high yield by esterifying an α-hydroxy carboxylic acid derivative to synthesize an α-hydroxy carboxylic acid ester derivative, and reducing this ester derivative in a protic solvent or a hydrous aprotic polar solvent in the presence of a sodium borohydride compound in the same reaction vessel.
Al-Catalyzed Enantioselective Alkylation of α-Ketoesters by Dialkylzinc Reagents. Enhancement of Enantioselectivity and Reactivity by an Achiral Lewis Base Additive
作者:Laura C. Wieland、Hongbo Deng、Marc L. Snapper、Amir H. Hoveyda
DOI:10.1021/ja053259w
日期:2005.11.1
An Al-catalyzed enantioselective method for additions of Me2Zn and Et2Zn to alpha-ketoesters bearing aromatic, alkenyl, and alkyl substituents is disclosed. Transformations are promoted in the presence of a readily available amino acid-based ligand and afford the desired products in excellent yields and in up to 95% ee. Investigations described illustrate that the presence of a Lewis basic additive can lead to significant enhancements in efficiency and enantioselectivity. A mechanistic model that provides a rationale for such effects is provided.
Electrocatalytic carboxylation of aromatic ketones with carbon dioxide in ionic liquid 1-butyl-3-methylimidazoliumtetrafluoborate to α-hydroxy-carboxylic acid methyl ester
作者:Qiuju Feng、Kelong Huang、Suqin Liu、Jingang Yu、Fangfei Liu
DOI:10.1016/j.electacta.2011.03.061
日期:2011.5
A new electrochemical procedure for the electrocatalytic carboxylation of aromatic ketones with carbon dioxide in ionic liquid, 1-butyl-3-methylimidazolium tetrafluoborate(BMIMBF4), to alpha-hydroxycarboxylic acid methyl ester was investigated for the first time. The electrochemical behavior of acetophenone in BMIMBF4 was studied by cyclic voltammetry with a reduction peak at -1.9V (vs. Ag). The electrolyses experiments were carried out in an undivided cell under mild conditions without any toxic solvents, catalysts and supporting electrolytes, followed by addition of an alkylating agent, affording the alpha-hydroxycarboxylic acid methyl ester in a moderate yield (62%). The results showed that the yields were strongly affected by various factors: temperature, current density, charge passed, electrode material and substrate concentration. Moreover, the ionic liquid was successfully recycled for this reaction. (C) 2011 Elsevier Ltd. All rights reserved.