纳米铝粉促进羰基化合物水相烯丙基化反应

氮气保护条件下,纳米铝在0.1 N NH₄Cl溶液中,能有效地促进羰基化合物与烯丙基溴进行Barbier-Grignard型烯丙基化反应,得到相应高烯丙醇。芳香族醛或酮的烯丙基化产率较高,而脂肪族羰基化合物反应产率低,反应产率受羰基空间位阻影响大,在同样条件下,邻羟基羰基化合物烯丙基化产物主要是赤式-邻二醇。     

FeCl3作用下的碘代醚化反应: 一种合成碘代环烯醚的方便方法

对FeCl₃作用下各种炔醇与碘的反应进行了详细研究, 结果表明在FeCl₃和碘的作用下, 炔醇发生分子内碘代环化反应生成碘代环烯醚, 产率为63%～90%. 在相同的反应条件下, 炔丙醇类则生成邻二碘化物, 产率为15%～88%. 该反应具有操作简单、底物适应广、反应快(3 h)和碘用量(0.5 equiv.)少等特点, 是制备碘代环烯醚和2,3-二碘代烯醇的好方法.     

二氧化碳促进的醛和酮等羰基化合物烯丙基化反应研究

加入二氧化碳可以促进羰基化合物的烯丙基化反应. 实验结果表明: 在1.0 MPa的二氧化碳和2 equiv.的锡存在下, 以THF/H₂O为反应介质, 芳香醛化合物与烯丙基溴可以顺利地发生烯丙基化反应得到较高的产率, 而芳香酮化合物和脂肪醛等与烯丙基溴反应只得到较低的产率.     

离子液体介质中FeCl3•6H2O催化下芳香醛与5,5-二甲基-1,3-环己二酮的缩合反应

考察了在离子液体1-正丁基-3-甲基咪唑四氟硼酸盐([bmim][BF₄])介质中, 芳香醛与5,5-二甲基-1,3-环己二酮的缩合反应. 实验结果表明, 在催化量的FeCl₃•6H₂O存在下, 该反应可高产率地生成氧杂蒽二酮类化合物3; 而在TMSCl/FeCl₃•6H₂O复合催化体系的催化下, 则得到氧杂蒽二酮类化合物的开环衍生物4, 反应具有非常好的选择性. 该论文提供的方法操作简单、产率高、选择性好而且对环境友好. 在反应结束后, 所用催化剂及离子液体都很容易回收, 并能有效重复使用.     

氯化镁催化醛、酮及亚胺的化学选择性还原

发展了一种操作简便、廉价实用的镁催化体系,用于醛、酮及α,β-不饱和醛/酮的选择性还原,制备了一系列醇类化合物.以温和的HBpin为还原剂,在没有酸或碱作为水解试剂的前提下,高选择性地还原羰基,体系中没有检测到硼酸酯副产物.对碘、溴、氯、氟、硝基、三氟甲基、氨甲基、炔基和酰胺等官能团具有良好的兼容性,在温和的条件下, MgCl2/HBpin催化体系不仅对羰基具有较高的催化活性,对亚胺类底物具有高效的催化效果.     

光动力化合物5-氨基乙酰丙酸的简便全合成

从γ-丁内酯出发, 首先发生醇解、氧化反应, 继而采用无溶剂法与硝基甲烷在KF/Al₂O₃催化下发生Henry反应, 再经湿Al₂O₃负载的CrO₃氧化得到5-硝基-4-羰基戊酸乙酯, 最后在Pd/C催化下还原得到5-氨基乙酰丙酸. 各步所合成化合物的结构经¹H NMR, IR, MS分析确证.     

FeCl3催化羰基化合物与芳烃的还原Friedel-Crafts烷基化反应

在二甲基氯硅烷作用下, FeCl3能催化羰基化合物(醛、酮)与芳烃及噻酚的还原Friedel-Crafts烷基化反应, 在温和的条件下一步实现羰基化合物的还原和C—C键的构造.     

FeCl3催化羰基化合物与芳烃的还原Friedel-′Crafts烷基化反应

在二甲基氯硅烷作用下,FeCl3能催化羰基化合物（醛、酮）与芳烃及噻酚的还原Friedel—Crafts烷基化反应,在温和的条件下一步实现羰基化合物的还原和C—C键的构造．     

无机锌盐催化脂肪醛的Biginelli反应

以无水乙醇为溶剂, 在回流温度下, 考察了四种无机锌盐[Zn(NO₃)₂, ZnSO₄, ZnCl₂及Zn(OAc)₂]催化脂肪醛的Biginelli反应的催化能力, 所用原料为7种脂肪醛、1,3-二羰基化合物和脲. 实验结果表明硝酸锌的催化效果强于其它三种无机锌盐, 产率最高可以达到94%. FTIR和¹H NMR分析结果证实了所合成的目标产物. 该反应操作简单、催化剂廉价易得.     

CuI催化的酰胺和溴苯的偶联反应研究

本文报道了一种新的催化体系 (CuI / 氨基酸 / K₃PO₄) 催化胺和芳香溴代化合物之间的交叉偶联反应，对于不同的底物都以较好的产率得到了产物。该反应操作简单，适用性广，并且试剂价格便宜。     

Biomimetic oxidation of alcohols by coenzyme PQQ-trimethyl ester

Oxidation of alcohols to corresponding carbonyl compounds by coenzyme PQQ-trimethyl ester was performed in the presence of aluminum t-butoxide or aluminum chloride under anaerobic conditions. Reduced PQQTME (PQQTMEH₂) was obtained by acidification of an aluminum complex of reduced PQQTME which was isolated in the reaction.     

Radical promoted cyclizations of aromatic carbonyl compounds to benzopyrans using titanocene(III) chloride

Aromatic carbonyl compounds undergo smooth intramolecular radical cyclization with alkenes or alkynes using titanocene(III) chloride to furnish the corresponding benzopyrans. The radical initiator, Cp₂TiCl, was prepared in situ from commercially available titanocene dichloride (Cp₂TiCl₂) and zinc dust in THF under argon.     

An Efficient One-pot Synthesis of β-Amino/β-Acetamido Carbonyl Compounds via ZrCl4-catalyzed Mannich-type Reaction

Zirconium(IV) chloride catalyzed efficient one-pot synthesis of β-amino/β-acetamido carbonyl compounds at room temperature is described. In the presence of ZrCl4, the three-component Mannich-type reaction via a variety of in situ generated aldimines, with various ketones, aromatic aldehydes and aromatic amines in ethanol, led to the formation of β-amino carbonyl compounds and the four-component Mannich-type reaction of aromatic aldehydes with various ketones, acetonitrile and acetyl chloride resulted in the corresponding β-acetamido carbonyl compounds in high to excellent yields. This methodology has also been applied towards the synthesis of dimeric β-amino/β-acetamido carbonyl compounds.     

Silica Chloride/Wet SiO2 as a Novel Heterogeneous System for Deprotection of Oximes,Hydrazones, and Semicarbazones

Abstract

Oximes, hydrazones, and semicarbazones can be converted to their corresponding carbonyl compounds in good to high yields by a combination of silica chloride and wet SiO₂.     

Facile Synthesis of Bis(indolyl)methanes Using LaCl3 · 7H2O as a Mild and Efficient Catalyst in Molten Salt Media

Efficient electrophilic substitution reaction of indole with various carbonyl compounds were carried out using a catalytic amount of LaCl₃ · 7H₂O in molten tetraethylammonium chloride as an ionic liquid to afford the corresponding bis(indolyl)methanes in excellent yields.     

NEW APPLICATIONS OF SOLID SILICA CHLORIDE (─SiO2Cl): EFFICIENT OXIDATION OF CYCLIC THIOACETALS,TMS, TBDMS,AND THP ETHERS TO THEIR CARBONYL COMPOUNDS BY SOLID SILICA CHLORIDE/KMnO4 SYSTEM

Solid silica chloride/KMnO₄ system oxidizes effectively aromatic and aliphatic cyclic thioacetals (1,3-dithiolanes, 1,3-dithianes) and silyl and pyranyl ethers into their corresponding carbonyl compounds in dry CH₃CN at room temperature in high yields. Over-oxidation of aldehydes to carboxylic acids has not been observed by this system. In the absence of silica chloride, KMnO₄ in dry CH³CN is an ineffective reagent for these oxidations.     

Tantalum(V) Chloride–Silica Gel: An Efficient Catalyst for Conversion of Carbonyl Compounds to 1,3‐Oxathiolanes

A variety of carbonyl compounds can be easily converted to the corresponding 1,3‐oxathiolanes in the presence of a catalytic amount of tantalum(V) chloride [TaCl₅] on silica gel in dichloromethane. Mild reaction conditions, efficiency, high yields, operational simplicity, and only 2.5 mol% of TaCl₅ catalyst are some of the major advantages of the procedure.     

Chemistry of iron carbonyl anions: Selective reduction of nitroarenes and α, β-unsaturated carbonyl compounds,and reductive dehalogenation of organic halides by (C2H5)4N+ HFe3(CO)11−

The tetraethylammonium undecacarbonylhydridotriferrate [(C₂H₅)₄N⁺ HFe₃(CO)₁₁^?] (I): which can be easily prepared in a two-step sequence from iron pentacarbonyl, triethylamine and tetraethylammonium chloride, selectively reduces nitroarenes to amines and α, β-unsaturated carbonyl compounds to the corresponding saturated compounds both in good yield. I reacts with some organic halides to give dehalogenated products.     

Catalytic conjugate addition of heterocyclic compounds to α,β-unsaturated carbonyl compounds by hafnium salts and scandium salts

The hafnium chloride (HfCl₄) and scandium chloride (ScCl₃) catalyzed conjugate additions of heterocyclic compounds, such as indoles, pyrrole, pyrazole, and imidazole, have been demonstrated. Hafnium chloride effectively catalyzed the conjugate addition of indoles to α,β-unsaturated carbonyl compounds, and the addition product was obtained in high yield. The reaction of pyrrole was also catalyzed by HfCl₄ or ScCl₃, and produced 2,6-dialkylated pyrroles up to 99% yields. Furthermore, the conjugate addition of the 1-position of the pyrazoles and imidazole occurred, and produced several substituted heterocyclic compounds in good yields.     

Indoles

It has been found that arylhydrazones of carbonyl compounds smoothly undergo rearrangement into the corresponding indoles under the action of strong alkylating agents such as benzyl chloride, allyl bromide, and dimethyl sulfate in boiling methanol. The use of arylhydrazines substituted at the α-nitrogen atom leads to the formation of N-subsituted indoles; However, where a hydrazine of the type of ArNHNH₂ is used, a mixture of the corresponding indole and of the indole substituted on the nitrogen atom by the radical of the alkylating compound is formed.