有机硒催化的氧化脱氧在温和的条件下提供了酮和醛。反应使用过氧化氢和空气作为清洁氧化剂,并导致了无废料和无金属的脱保护方案,用于羰基保护策略以及绿色合成的酮和醛。通过控制实验以及硒77核磁共振(77 Se NMR)测试,已经研究了这种有趣的有机硒催化反应的机理。这种新颖的反应大大扩展了有机硒催化的应用范围。
基于小分子的亲电子化合物,例如1-氯-2-,4-二硝基苯(CDNB)和1-氯-4-硝基苯(CNB)被用作半胱氨酸和硒代半胱氨酸蛋白的抑制剂。CDNB已被广泛用于确定谷胱甘肽S的活性转移酶并耗尽哺乳动物细胞中的谷胱甘肽(GSH)。而且,已证明CDNB不可逆地抑制硫氧还蛋白还原酶(TrxR),这是一种催化硫氧还蛋白(Trx)还原的硒酶。哺乳动物TrxR具有C端活性位点基序Gly-Cys-Sec-Gly,半胱氨酸和硒代半胱氨酸残基都可能是亲电子试剂的靶标。在本文中,我们报告了一系列半胱氨酸和硒代半胱氨酸衍生物的稳定性,这些衍生物可被视为硒代酶-抑制剂复合物的模型。我们证明这些衍生物与H 2 O 2反应生成相应的亚硒酸盐,将其自发消除以生成脱氢丙氨酸。相反,半胱氨酸衍生物对这种消除反应是稳定的。我们还首次证明了从硒代半胱氨酸衍生物中消除的芳基硒物种通过在GSH存在下催化H 2 O 2的还原而表现出
Thermal reaction of alkylarylselenoxides in the presence of water or methanol in the supercage of zeolite NaY gave beta-hydroxy- or beta-methoxyalkyl aryl selenides, respectively, and NaY played a novel role to stabilize reactive ArSeOH and to separate an anion of -OH from a carbonium ion which was simultaneously present with the -OH in a supercage.
The polyhedral nature of selenium-catalysed reactions: Se(<scp>iv</scp>) species instead of Se(<scp>vi</scp>) species make the difference in the on water selenium-mediated oxidation of arylamines
Selenium-catalysed oxidations are highly sought after in organic synthesis and biology. Herein, we report our studies on the on water selenium mediated oxidation of anilines. In the presence of diphenyldiselenide or benzeneseleninic acid, anilines react with hydrogen peroxide, providing direct and selective access to nitroarenes. On the other hand, the use of selenium dioxide or sodium selenite leads
硒催化氧化在有机合成和生物学中备受追捧。在此,我们报告了我们对水硒介导的苯胺氧化的研究。在二苯基二硒化物或苯硒酸存在下,苯胺与过氧化氢反应,直接和选择性地获得硝基芳烃。另一方面,使用二氧化硒或亚硒酸钠会产生氧化偶氮芳烃。仔细的机理分析和77 Se NMR 研究表明,只有 Se( IV ) 物质,如苯过氧硒酸,是参与在水中运行并导致硝基芳烃的催化循环的活性氧化剂。虽然最近在有机溶剂中发生的其他硒催化氧化反应已被证明是通过 Se( VI) 关键中间体,苯胺在水中氧化成硝基芳烃没有。这些发现揭示了有机硒催化转化的多方面性质,并开辟了利用硒基催化的新方向。
Hydrolytic selenoxide elimination reaction for the preparation of 2-chloro-1-olefins
作者:Lars Engman
DOI:10.1016/s0040-4039(00)95954-9
日期:——
from terminal olefins by a sequence involving Markownikoff-addition of PhSeCl, chlorination of the resulting β-chloroalkyl phenyl selenides with SO2Cl2 and, after recrystallization, hydrolysis/selenoxideelimination in a two-phase system.
Chemoselective α,β‐Dehydrogenation of Saturated Amides
作者:Christopher J. Teskey、Pauline Adler、Carlos R. Gonçalves、Nuno Maulide
DOI:10.1002/anie.201808794
日期:2019.1.8
We report a method for the selective α,β‐dehydrogenation of amides in the presence of other carbonyl moieties under mild conditions. Our strategy relies on electrophilic activation coupled to in situ selective selenium‐mediated dehydrogenation. The α,β‐unsaturated products were obtained in moderate to excellent yields, and their synthetic versatility was demonstrated by a range of transformations.
我们报告了一种在温和条件下在其他羰基存在下选择性 α,β-脱氢酰胺的方法。我们的策略依赖于亲电激活与原位选择性硒介导的脱氢作用相结合。α,β-不饱和产物以中等至优异的收率获得,并且它们的合成多功能性通过一系列转化得到证明。机理实验表明亲电子 Se IV物质的形成。
Rapid and Ecofriendly Esterification of Alcohols with 2-Acylpyridazinones
Atom-economical esterification is of great importance in green chemistry. In this work, we demonstrated the catalyst and additive free esterification of alcohols by their reaction with 2-acyl-4,5-dichloropyridazin-3(2H)-ones without solvent at $100^\circ}C$. Aliphatic and aromatic alcohols were converted into the corresponding esters in good to excellent yields. It is noteworthy that the reaction is solvent-free, atom-economic, easy-workup, and rapid and that the process is inexpensive.