Department of Chemistry , Indian Institute of Technology Kharagpur , Kharagpur 721302 , West Bengal , India.
Org Lett. 2018 Nov 2;20(21):6920-6924. doi: 10.1021/acs.orglett.8b03063. Epub 2018 Oct 25.
A one-pot, protecting-group-free benzannulation of 2-alkenylindoles with readily available 1,3-dicarbonyls is demonstrated to construct structurally diverse carbazoles. The use of a cheap Brønsted acid catalyst and air as the sole oxidant exemplifies the economic viability of this protocol. The execution of four different reactions successively to generate the medicinally important indolocarbazole core is also achieved. This one-pot protecting-group-free method paved the way for the total synthesis of three medicinally important alkaloids, namely staurosporinone, arcyriaflavin A, and 7-hydroxy-K252c.
本文展示了一种简便的一锅法，通过 2-烯基吲哚与易得的 1,3-二羰基化合物的保护基自由苯并环化反应，构建了结构多样的咔唑类化合物。该反应使用廉价的布朗斯特酸催化剂，以空气作为唯一氧化剂，体现了该方法的经济可行性。此外，还成功地连续进行了四个不同的反应，生成了具有重要药用价值的吲哚咔唑核心。这种一锅法、无需保护基的方法为三种具有重要药用价值的生物碱（即：staurosporinone、arcyriaflavin A 和 7-羟基-K252c）的全合成铺平了道路。
