Indium Mediated Conjugate Addition of Allyl Bromide to Nitroalkenes in DMF—H2O Media

Allylindium bromide prepared by metallic indium and allyl bromide was added to nitroalkenes to give conjugate addition compounds in moderate to good yields in an aqueous media.     

Enantioselective Organocatalyzed Michael Addition of Isobutyraldehyde to Maleimides in Aqueous Media

Thiourea was introduced into (R,R)-1,2-diphenylethylenediamine as an organocatalyst to promote the reaction between isobutyraldehydes and maleimides. Enantioselective Michael addition reaction was carried out as an eco-friendly method using water as the solvent. As a result of the reaction between isobutyraldehyde and maleimide, ≥97% yield and 99% enantioselectivity were obtained at a low catalyst loading of 0.01 mol%. The solvent effect can be explained by theoretical calculations that indicate the participation of a transition state, in which the CF₃ substituent of the catalyst is a hydrogen bond activated by the surrounding water molecules. This discovery enabled the use of low catalyst loading in the organic reactions of chiral substances for pharmaceutical applications. Furthermore, a solvent effect for Michael reaction of the organocatalysts was proposed, and the organic reaction mechanisms were determined through quantum calculations.     

A Simple One-pot Synthesis of 3,5-Dicyano-1,2-dihydropyrid-2-ones in Aqueous Media

A simple and clean synthesis of 3,5-dicyano-1,2-dihydropyrid-2-ones by a one-pot three-component reaction of malononitrile, aromatic aldehydes and 2-cyanoacetamide or 2-cyanothioacetamide has been achieved in an aqueous solution with potassium carbonate as a base under microwave irradiation without a phase transfer reagent. This protocol has the advantages of short reaction time （5-8 min） and convenient work-up.     

Reaction of 2-(2-Cyanoethyl)-1,1-dimethylhydrazine with Prop-2-ynyl Bromide, 1,3-Dibromopropyne,and Allyl Bromide

The reactions of 2-(2-cyanoethyl)-1,1-dimethylhydrazine with prop-2-ynyl bromide, 1,3-dibromopropyne, and allyl bromide involve alkylation by a tertiary nitrogen atom to form 2-(2-cyanoethyl)-1,1-dimethyl-1-(prop-2-ynyl)-, 1-(3-bromoprop-1-ynyl)-2-(2-cyanoethyl)-1,1-dimethyl-, and 1-allyl-2-(2-cyanoethyl)-1,1-dimethylhydrazinium bromides.     

Indium-Mediated Synthesis of Homoallyl Alcohols in the Aqueous Phase

The indium-mediated Barbier-type allylation reaction of aldehydes with allyl bromide, which gives corresponding homoallyl alcohols, was investigated. The reaction medium and the effects of substituents were discussed in detail. The results showed that various aldehydes, including aromatic, heterocyclic, and aliphatic aldehydes, with different substituents could all react well with excellent yields of 91–97% in aqueous tetrahydrofuran at room temperature within about 1 h.

Zinc-Promoted Barbier-Type Reaction of Propargyl Bromide with Aldehydes in Aqueous Media

In the prese of metallic zinc, propargyl bromide is found to react with aldehydes at room temperature in tetrahydrofurane-saturated aqueous ammonium chloride (5:2) to afford the corresponding homopropargylic alcohols in moderate to high yields together with small amounts of α-allenic alchohols.     

Henry Reaction in Aqueous Media：Chemoselective Addition of Aldehydes

The chemoselective addition of aldehydes in aquoues medium was obtained under mild condition using improved Henry reaction.     

含分子内氢键的苯硫酚在水相中的Michael加成反应

苯硫酚的巯基是一个较强的亲核基团,对α,β-不饱和双键的Michael加成反应已有报道．但是当巯基的邻位存在与其形成氢键的基团时,如果按文献条件进行反应,或者反应无法进行,或者要使用反应条件苛刻的丁基锂,或者使用吡啶等毒性较大的反应溶剂,而且产率较低．本文选择     

可聚合囊泡体系(烯丙基-二甲基-十二烷基溴化胺和十二烷基硫酸钠)在溶液中的盐效应

高稳定的囊泡广泛用于制作生物模型、药物输送以及合成纳米材料的模板。获得高稳定囊泡结构的重要方法之一是用聚合反应固定囊泡结构。作为可聚合囊泡制备的前期基础工作,研究了一种可聚合的囊泡体系：1-丙烯基－2,2,二甲基－十二烷基溴化胺（ADDB）和ADDB与十二烷基磺酸钠（SDS）的等摩尔比混合体系。该囊泡体系即使在高浓度盐水中也能够自发地形成均相的囊泡溶液。在聚合之前,采用动态激光光散射（DLS）、冷冻蚀刻透射电镜（FF-TEM）技术研究了可聚合囊泡的盐效应。DLS测试发现没有盐存在时,囊泡大小为83 nm,盐的浓度增加到250 mmol/L时,囊泡尺寸增大到250 nm。然而继续增大盐浓度到1000 mmol/L, 囊泡尺寸减小到180nm. FF-TEM结果发现盐浓度小于150 mM时, 单个囊泡为70 nm左右,然而明显存在囊泡的絮凝与融合;当盐浓度增加到400 mM时,单个囊泡尺寸减小到20 nm. 因此DLS 观测到囊泡尺寸增大的原因是由于囊泡的絮凝与融合;而尺寸减小的原因是由于在高盐浓度下,盐屏蔽了带电颗粒之间的静电相互作用,在熵增的驱使下,大囊泡变成小囊泡。     

Addition of Nitrile Oxides to Aryl Allyl Ethers

3,5-Disubstituted isoxazolines with an aryloxymethyl group in position 5 have been synthesized. The [2+3] cycloaddition reaction of benzonitrile oxide to a 5-chlorosalicylic acid derivative containing two allyl groups occurs to give a compound with an oxazolinylmethyl fragment both in the ester and the ether parts of the molecule. The addition of nitrile oxides to the aryl allyl ethers occurs regiospecifically to give the 5-substituted isomer.     

The Substituent Effects of tert-Butyl Radical Addition to 2-Substituted Allyl Chlorides

The relative rates for the addition reactions of tert-butyl radical to 2-substituted ally chlorides I have een determined. The correlation of log k/k₀, vs. σ_m gives a ρ mvalue of 3.59 with correlation coefficient of 0.930. When the substituent CH₂Cl is excluded, correlation coefficient raises to 0.990 and ρ value becomes 3.39. The large p value and the deviation of relative rate of substituent CH₂C1 are discussed.     

1,4-Asymmetric Induction in the Chromium(II)- and Indium-Mediated Coupling of Allyl Bromides to Aldehydes

A series of allyl bromides bearing an ethereal stereogenic substituent at C-2 were synthesized from methyl acrylate. These were coupled with a range of aldehydes under chromium(II) chloride-mediated conditions to afford syn-4-alkoxyalkan-1-ols in good yield and diastereoselectivity. The effect of altering the nature of the ethereal group and alkyl substituent upon the diastereoselectivity of the reaction was also investigated. The relative stereochemistry was proved by X-ray structure analysis. The work was extended to replace the chromium(II) chloride with indium metal, and this also afforded syn-4-alkoxyalkan-1-ols in good yield and diastereoselectivity.     

Novel Octapeptide as an Asymmetric Catalyst for Michael Reaction in Aqueous Media

In this work, three forms of a novel octapeptide have been evaluated as asymmetric catalysts for the Michael reaction. Low quantity catalyst loading, ecofriendly solvents, and reusability of organocatalyst successfully applied to attain excellent yields and moderate enantioselectivities in the Michael reaction.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resources: Full experimental and spectral details.]     

Regioselective Reactions of Pyridine-2-sulfenyl Bromide with Vinyl and Allyl Ethers

Russian Journal of General Chemistry - Annulation reactions of pyridine-2-sulfenyl bromide with vinyl and allyl ethers proceeded regioselectively, but with opposite regiochemistry. Reactions with...     

Novel Reductive Dimerization Cyclization of 1,1-Dicyanoalkenes Mediated by Zinc in Aqueous Media

Zinc-mediated reductive dimerization cyclization of 1,1-dicyanoalkenes 1 occurs to give functionalized cyclopentenes 2(cis) and 3(trans) in good yields under saturated aqueous NH₄Cl-THF solution at room temperature. 3 is major product.     

Oxidation of Palladium with Allyl Bromide and Iodine in Dimethylformamide

The kinetic features of palladium oxidation with allyl bromide and iodine in dimethylformamide were determined. The apparent equilibrium constants, enthalpies, and entropies of reactant adsorption on the palladium surface were calculated.     

水中2,4,6-三芳基-3-芳酰基-4-羟基环己基-1,1-二甲腈的洁净合成

研究了十六烷基三乙基溴化铵(HTEAB)催化、水介质中, 查尔酮和丙二腈加热回流合成系列2,4,6-三芳基-3-芳酰基-4-羟基环己基-1,1-二甲腈化合物. 产物经¹H NMR, IR和元素分析进行了结构表征. 此方法具有反应条件温和、操作简便、产率较高、环境友好的优点.     

Effect of Co-solvent on the Palladium Catalyzed Alkoxycarbonylation of Allyl Bromide in Supercritical CO_2

We have studied the palladium-catalyzed alkoxycarbonylation of allyl bromide in supercritical (sc) CO2 and found the reaction rate in sc CO2 was lower than those in some organic solvents1. The possible reason was the lower solubility of sc CO2 for the palladium catalyst. As an effective approach to improve the solubility of varieties of solutes, cosolvent such as ethanol has been widely used in the sc CO2 extraction2,3. Based on the above consideration, we chose several organic reagents…