Copper-Catalyzed One-Pot Cross-Dehydrogenative Thienannulation: Chemoselective Access to Naphtho[2,1-<i>b</i>]thiophene-4,5-diones and Subsequent Transformation to Benzo[<i>a</i>]thieno[3,2-<i>c</i>]phenazines
A facile, cost-effective, and highly efficient copper-catalyzed, TEMPO-mediated straightforward synthesis of 2,3-disubstituted naphtho[2,1-b]thiophene-4,5-diones has been achieved via cross-dehydrogenative thienannulation. The reaction proceeded via in situ generated naphthalene-1,2-diones by dearomatization of β-naphthols, followed by oxidative heteroannulation with α-enolic dithioesters chemoselectively
通过交叉脱氢噻吩鎓制得了一种简便,经济高效且高效的铜催化,TEMPO介导的2,3-二取代萘并[ 2,1- b ]噻吩-4,5-二酮直接合成方法。反应通过原位生成的萘-1,2-二酮进行,方法是将β-萘酚脱芳香化,然后在敞口烧瓶中用α-烯醇二硫代酯进行化学选择性氧化杂化。此外,萘并[2,1 - b ]噻吩-4,5-二酮与邻苯二胺一起进行1-脯氨酸催化的交叉脱水偶联,从而使五环苯并[ a ]噻吩并[3,2- c在无溶剂条件下,[[]]吩嗪具有良好的收率。控制实验很好地支持了该级联反应序列的机械原理。