transformation of alkynes by controlled manipulation of TsNBr2 mediated process. Alkynes could be readily converted to ketones and α-bromoketones via an oxybromination–debromination sequence. When alkynes are treated successively with TsNBr2, KI and Na2SO3 in a mixture of acetone and water at roomtemperature, corresponding ketones were obtained. On the other hand, treatment of alkynes with TsNBr2 and
通过控制TsNBr 2介导的过程,开发了炔烃的氧化转化的新方法。炔烃可以很容易地通过氧溴化-脱溴序列转化为酮和α-溴代酮。在室温下,在丙酮和水的混合物中依次用TsNBr 2,KI和Na 2 SO 3处理炔烃时,可获得相应的酮。另一方面,用TsNBr 2和Na 2 SO 3处理炔烃在室温下,在乙酸乙酯,丙酮和水的混合物中,可生成相应的α-溴代酮。还可以在室温下使用TsNBr 2在很短的时间内由相应的炔烃合成1-溴炔烃。在所有情况下,都可获得相应产品的优异收率。
Rapid access to unsymmetrical 1,3-diynes and 2,5-disubstituted thiophenes under ligand and Pd/Ni-free Cu-catalysis
作者:Maddali L. N. Rao、Sk Shamim Islam、Priyabrata Dasgupta
DOI:10.1039/c5ra15705f
日期:——
A Pd/Ni-free copper-catalysed tandem synthesis was realized for rapid access to unsymmetrical 1,3-diynes from 1,1-dibromoalkenes and terminal alkynes. This method was extended to the straightforward synthesis of unsymmetrical 2,5-disubstitutedthiophenes in a one-pot operation.
Highly efficient and recyclable catalyst for the direct chlorination, bromination and iodination of terminal alkynes
作者:Wei Shi、Zhipeng Guan、Peng Cai、Hao Chen
DOI:10.1016/j.jcat.2017.07.019
日期:2017.9
Direct halogenation, including chlorination, bromination and iodination of terminalalkynes, are of great importance in organic synthesis. Here an efficient and recyclable nano-Ag/g-C3N4 catalyst system was developed and proved to be remarkably active with 39 examples varied from chlorination, bromination to iodination, of which 14 runs have yielded more than 95% of the product. Recycling of the catalyst
直接卤化,包括末端炔烃的氯化,溴化和碘化,在有机合成中非常重要。在此,开发了一种有效且可循环利用的纳米Ag / gC 3 N 4催化剂体系,并证明其具有显着的活性,从氯化,溴化到碘化的39种实例中,有14种的收率超过了95%。在几次运行后,也实现了催化剂的再循环而没有明显的活性损失:即使在苯乙炔的溴化过程中进行了5次运行,也观察到99%的收率。该催化剂系统成本低廉且易于制备,使得该方法通用,方便且经济。
A convenient route to 1,3-diynes using ligand-free Cadiot-Chodkiewicz coupling reaction at room temperature under aerobic conditions
作者:Sujatha Asha、Sasidharan Anjana、Anns Maria Thomas、Minu Elizabeth Thomas、K. R. Rohit、K. Keerthi Krishnan、Sankuviruthiyil M Ujwaldev、Gopinathan Anilkumar
DOI:10.1080/00397911.2018.1554142
日期:2019.1.17
Abstract In this study, we report a copper-catalyzed ligand-free Cadiot-Chodkiewicz couplingreaction. No additives or ligands are required for this Cu-catalyzed C(sp)-C(sp) couplingreaction of terminal alkynes with alkynyl halides. The low cost of copper catalyst, excellent yield of the products, suppression of side-products and mild reaction conditions are the major advantages of this protocol.