DMSO and in water in the presence of tetrabutylammonium bromide (TBAB) as a phase transfer catalyst. Negligible background reactions (i.e., negative control experiment in the absence of keratin protein) were observed in these solvent systems. Aromatic aldehydes bearing electron-donating groups and aliphatic aldehydes showed poor or no conversion, respectively. In general, the reactions in water/TBAB
In this manuscript we report a critical evaluation of the ability of natural DNA to mediate the nitroaldol (Henry) reaction at physiological temperature in purewater. Under these conditions, no background reaction took place (i.e., control experiment without DNA). Both heteroaromatic aldehydes (e.g., 2-pyridinecarboxaldehyde) and aromatic aldehydes bearing strong or moderate electron-withdrawing groups
在这份手稿中,我们报告了对天然 DNA 在生理温度下在纯水中介导硝基醛醇 (Henry) 反应能力的批判性评估。在这些条件下,没有发生背景反应(即没有 DNA 的对照实验)。杂芳香醛(例如,2-吡啶甲醛)和带有强或中度吸电子基团的芳香醛都与硝基甲烷发生了令人满意的反应,符合一级动力学,并在 24 小时内以良好的收率提供了相应的 β-硝基醇。相反,具有给电子基团的脂肪醛和芳香醛要么不反应,要么转化率低。而且,我们发现,当许多不含金属的有机缓冲剂用作反应介质而不添加外部催化剂时,它们可以有效地促进亨利反应。这是一个重要的观察结果,因为传统上低估了化学过程中有机缓冲剂的影响。
Per-6-amino-β-cyclodextrin as a Reusable Promoter and Chiral Host for Enantioselective Henry Reaction
A highly efficient enantioselective Henry reaction has been carried out using per-6-ABCD as a supramolecular chiral host and promoter to give the corresponding adduct with high yield (up to 99%) and enantiomeric excess (up to 99%). Per-6-ABCD also promotes the diastereoselective Henry reaction in a syn-selective manner to give the adduct up to 99% yield with 99:1 syn/anti selectivity. The enantiomeric excess of the syn-adduct is 99%. The catalyst is recovered and reused without loss in its activity.
Diastereoselective Nitroaldol Reaction Catalyzed by Binuclear Copper(II) Complexes in Aqueous Medium
作者:Rajendran Arunachalam、Chirayil S. Aswathi、Anjan Das、Rukhsana I. Kureshy、Palani S. Subramanian
DOI:10.1002/cplu.201402200
日期:2015.1
moiety and an oxygen‐rich oxalate dihydrizide/malonic dihydrizide spacer moiety, as well as their binuclear metal complexes [Cu212] and [Cu222], which adopt a 1:1 metal/ligand ratio, were synthesized and characterized. Both complexes were screened for their catalytic activity in the nitroaldolreaction, in which [Cu212] worked efficiently as catalyst for both substituted benzaldehyde and pyridinecarboxaldehyde