LASOL-CCQFA, Universidade Federal de Pelotas-UFPel, P.O. Box 354, Pelotas 96010-900, RS, Brazil.
Molecules. 2021 Apr 19;26(8):2378. doi: 10.3390/molecules26082378.
We describe herein an alternative transition-metal-free procedure to access 3,4-bis(butylselanyl)selenophenes and the so far unprecedented 3-(butylselanyl)-4-alkoxyselenophenes. The protocol involves the 5--dig electrophilic cyclization of 1,3-diynes promoted by electrophilic organoselenium species, generated in situ through the oxidative cleavage of the Se-Se bond of dibutyl diselenide using Oxone as a green oxidant. The selective formation of the title products was achieved by controlling the solvent identity and the amount of dibutyl diselenide. By using 4.0 equiv of dibutyl diselenide and acetonitrile as solvent at 80 °C, four examples of 3,4-bis(butylselanyl)selenophenes were obtained in moderate to good yields (40-78%). When 3.0 equiv of dibutyl diselenide were used, in the presence of aliphatic alcohols as solvent/nucleophiles under reflux, 10 3-(butylselanyl)-4-alkoxyselenophenes were selectively obtained in low to good yields (15-80%).
我们在此描述了一种替代的过渡金属免费程序，用于访问 3,4-双（丁基硒基）硒吩和迄今为止前所未有的 3-（丁基硒基）-4-烷氧基硒吩。该方案涉及通过电活性有机硒物种促进 1,3-二炔的 5--dig 亲电环化，该电活性有机硒物种通过使用 Oxone 作为绿色氧化剂氧化二丁基二硒醚的 Se-Se 键原位生成。通过控制溶剂的性质和二丁基二硒醚的用量，可以实现标题产物的选择性形成。在 80°C 下使用 4.0 当量的二丁基二硒醚和乙腈作为溶剂时，以中等至良好的收率（40-78%）获得了四个 3,4-双（丁基硒基）硒吩的实例。当使用 3.0 当量的二丁基二硒醚时，在回流条件下，脂肪醇作为溶剂/亲核试剂存在下，以低至良好的收率（15-80%）选择性地获得 10 个 3-（丁基硒基）-4-烷氧基硒吩。
