Laser-flash photolysis of naphthyl diselenides; reactivities of naphthylseleno radicals
摘要:
Transient absorption spectra of 1-naphthylseleno (1-NaphSe(.)), and 2-naphthylseleno (2-NaphSe(.)) radicals, which are generated by laser-flash photolysis of the corresponding diselenides, were observed. The reactions of 1-NaphSe(.), and 2-NaphSe(.) with 2-methyl-1,3-butadiene and alpha-methylstyrene were investigated by following the decay rates of these seleno radicals. By both steady-state and laser-flash photolysis, it is proved that these seleno radicals add to alkenes in a reversible manner. The reaction rate constants for such reversible addition reactions were determined by conducting the reaction in the presence of O(2), which traps selectively the carbon-centered radicals formed by the addition reaction of the seleno radicals to the alkenes. The reactivity of 2-NaphSe(.) is higher than that of 1-NaphSe(.), both of which are less reactive than PhSe .. These reactivities were interpreted with the properties of SOMO calculated by MO method. (C) 1998 John Wiley & Sons, Inc.
Nucleophilic cleavage of lactones and esters with zinc selenolates prepared from diselenides in the presence of Zn/AlCl3
作者:Mohammad Nazari、Barahman Movassagh
DOI:10.1016/j.tetlet.2008.11.036
日期:2009.1
The utility of zinc selenolates for effecting nucleophilic cleavage of simple lactones and esters has been investigated. When zinc selenolate generated via Zn/AlCl3-promoted cleavage of diselenides was reacted with simple lactones and esters, efficient nucleophilic alkyl–oxygenbondcleavage proceeded generating the corresponding carboxylic acids in moderate to excellent yields.
Atom-economical selenation of electron-rich arenes and phosphonates with molecular oxygen at room temperature
作者:Samir Kumar Bhunia、Pritha Das、Ranjan Jana
DOI:10.1039/c8ob02792g
日期:——
An environmentally benign selenation of electron-rich arenes and phosphonates is developed adopting a novel recycle–reuse–reduce strategy for selenol by oxygen.
一种采用新颖的循环-重复利用-减少策略,通过氧气对富电子芳烃和膦酸酯进行环保的硒化反应被开发出来。
Regioselective, Solvent- and Metal-Free Chalcogenation of Imidazo[1,2-<i>a</i>
]pyridines by Employing I<sub>2</sub>
/DMSO as the Catalytic Oxidation System
作者:Jamal Rafique、Sumbal Saba、Alisson R. Rosário、Antonio L. Braga
DOI:10.1002/chem.201600800
日期:2016.8.8
molecular‐iodine‐catalyzed chalcogenations (S and Se) of imidazo[1,2‐a]pyridines were achieved by using diorganoyl dichalcogenides undersolvent‐freeconditions. This approach afforded the desired products that had been chalcogenated regioselectively at the C3 position in up to 96 % yield by using DMSO as an oxidant, in the absence of a metal catalyst, and under an inert atmosphere. This mild, green approach allowed
通过在无溶剂条件下使用二有机基二卤化氢实现咪唑并[1,2- a ]吡啶的高效分子碘催化硫属元素化(S和Se)。通过使用DMSO作为氧化剂,在没有金属催化剂的情况下,并且在惰性气氛下,该方法提供了所需的产物,该产物已经在C3位置进行了区域硫磺化,产率高达96%。这种温和的绿色方法可以制备具有结构多样性的不同类型的硫族化咪唑并[1,2- a ]吡啶。此外,当前协议还扩展到其他N杂环核。
Visible-light-induced metal and reagent-free oxidative coupling of <i>sp</i><sup>2</sup> C–H bonds with organo-dichalcogenides: synthesis of 3-organochalcogenyl indoles
作者:Vandana Rathore、Sangit Kumar
DOI:10.1039/c9gc00007k
日期:——
and halo either on indoles or aryl dichalcogenides showed amenability to the developed reaction. Furthermore, thiocyanation of the sp2 C–H bonds of indoles has been accomplished by this visible light induced method. A mechanistic understanding by UV-visible, EPR spectroscopy, and cyclic voltammetry suggests that light induces electron transferfrom the electron rich arene to oxygen providing an arene
Direct, Metal-free C(sp<sup>2</sup>
)−H Chalcogenation of Indoles and Imidazopyridines with Dichalcogenides Catalysed by KIO<sub>3</sub>
作者:Jamal Rafique、Sumbal Saba、Marcelo S. Franco、Luana Bettanin、Alex R. Schneider、Lais T. Silva、Antonio L. Braga
DOI:10.1002/chem.201705404
日期:2018.3.15
synthesis of 3‐Se/S‐indoles and imidazo[1,2‐a]pyridines through direct C(sp2)−H bond chalcogenation of heteroarenes with half molar equivalents of different dichalcogenides, using KIO3 as a non‐toxic, easy‐to‐handle catalyst and a stoichiometric amount of glycerol. The reaction features are high yields, based on atom economy, easy performance on gram‐scale, metal‐ and solvent‐free conditions as well as applicability
本文中,我们报告了一种更环保的协议,该方法通过杂芳烃的直接C(sp 2)-H键硫代半数当量的不同二硫代半乳糖苷合成3-Se / S-吲哚和咪唑并[1,2- a ]吡啶KIO 3是一种无毒,易于操作的催化剂和化学计量的甘油。该反应的特征是基于原子经济性的高收率,在克级,无金属和无溶剂条件下易于操作以及适用于不同类型的N-杂芳烃。