Department of Chemistry, Indian Institute of Science Education and Research, Bhopal, MP 462 023, India.
J Org Chem. 2013 Feb 15;78(4):1434-43. doi: 10.1021/jo302480j. Epub 2013 Jan 31.
A transition-metal-free synthetic method has been developed for the synthesis of unsymmetrical diaryl chalcogenides (S, Se, and Te) from diaryl dichalcogenides and arenes under oxidative conditions by using potassium persulfate at room temperature. Variously substituted arenes such as anisole, thioanisole, diphenyl ether, phenol, naphthol, di- and trimethoxy benzenes, xylene, mesitylene, N,N-dimethylaniline, bromine-substituted arenes, naphthalene, and diaryl dichalcogenides underwent carbon-chalcogen bond-forming reaction to give unsymmetrical diaryl chalcogenides in trifluoroacetic acid. To understand the mechanistic part of the reaction, a detailed in situ characterization of the intermediates has been carried out by (77)Se NMR spectroscopy by using diphenyl diselenide as the substrate. (77)Se NMR study suggests that electrophilic species ArE(+) is generated by the reaction of diaryl dichalcogenide with persulfate in trifluoroacetic acid. The electrophilic attack of arylchalcogenium ion on the arene may be responsible for the formation of the aryl-chalcogen bond.
已开发出一种无过渡金属的合成方法，可在室温下使用过硫酸钾将二芳基二硫醚和芳烃氧化为不对称二芳基硫族化合物（S、Se 和 Te）。各种取代的芳烃，如苯甲醚、硫代苯甲醚、二苯醚、苯酚、萘酚、二和三甲氧基苯、二甲苯、均三甲苯、N,N-二甲基苯胺、溴代芳烃、萘和二芳基二硫醚，发生碳-硫族键形成反应，在三氟乙酸中生成不对称二芳基硫族化合物。为了理解反应的机理部分，通过使用二苯二硒醚作为底物的（77）Se NMR 光谱对中间体进行了详细的原位表征。（77）Se NMR 研究表明，在三氟乙酸中，二芳基二硫醚与过硫酸盐反应生成亲电物种 ArE(+)。芳基硒翁离子对芳烃的亲电攻击可能负责芳基-硫键的形成。
