An environmentally friendly protocol for the synthesis of C3‐selenylated 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones was developed via the electrochemical oxidation, iodide‐catalyzed selenation of 4H‐pyrido[1,2‐a]pyrimidin‐4‐ones with diaryl (alkyl) diselenides under oxidant‐ and external electrolyte‐free conditions. Only by using 10 mol % of KI as catalyst and electrolyte, the selenation can proceed efficiently, and give corresponding products in good to excellent yields, avoiding the use of excess oxidant or iodinated reagents.

Owing to their special biological activities, organic selenium heterocyclic compounds have widely applications in organic chemistry and drug synthesis. A series of methods for the synthesis of organoselenide heterocyclic compounds have been reported, however, shortcomings still exist. In this paper, an effective method for the synthesis of 3-aryl(alkyl)selenylcoumarin derivatives via the ICl-catalyzed selenation of coumarins with diaryl(alkyl)diselenide at room temperature is reported. In addition, this method is also suitable for the construction of Csp2-Se bonds of other heterocyclic compounds. Compared to previous methods, this method has the advantages of mild conditions and wide functional groups tolerance, providing a general pathway to organoselenide heterocyclic compounds. Keywords Iodine cation-catalyzed selenation; Construction of Csp2-Se; Heterocyclic compounds; Diaryl(alkyl)diselenides 香豆素衍生物具有良好的生物活性, 成为抗肿瘤药 物研发的研究热点 [1][2][3][4] . 与其他抗肿瘤活性药物相比, 香 豆素衍生物具有药理运用广泛、分子量小、合成简便和 毒性弱等特点 [5][6][7] . 在农业生产方面, 香豆素衍生物可以 作为杀虫剂和植物保护素 [8][9][10] . 此外, 香豆素衍生物作 为荧光探针, 可以应用于水体中污染物分析 [11][12][13] . 同时, 香豆素类化合物还可以应用于制作荧光增白剂、荧光指 示剂以及荧光染料 [14][15][16] . 由于香豆素衍生物在很多领域 具有重要的应用, 众多关于香豆素及其衍生物合成的方 法被相继报道 [17][18][19][20] .有机硒化合物因其良好的生物学活性, 在医药和有 机合成中具有广泛的应用, 特别是在抗癌、 心血管保护、 抗病毒、免疫调节及神经保护等方面均具有重要应 用 [21][22][23][24] . 硒原子可以作为电子供体或氢键受体, 以修饰 酶活性位点的化学特征, 因此硒化的杂环化合物具有独 特的生物学活性与化学性质 [25] . 目前, 关于香豆素衍生 物 C sp 2-Se 键构建方法主要有以下几种: 卤代烃脱卤芳 硒化反应是构建 C-Se 键的重要方法, 但该方法至少需 要等物质的量的卤素作为预卤化试剂, 不符合原子经济 性要求 [26] . 杂环化合物 C-H 交叉脱氢氧化偶联(CDC) 反应在一定程度上解决了预官能团化问题, 且具有很好 的原子经济性. 最近, 曲阜师范大学魏伟课题组报道了 (NH 4 ) 2 S 2 O 8 存在下, 可见光诱导 4-苯胺香豆素和二芳基 二硒化物 C-H 交叉脱氢氧化偶联反应制备有机硒香豆