An atom-economical and environmentally benign approach for the synthesis of 3-indolylquinones was achieved successfully via direct oxidative C–C coupling of quinones/hydroquinones with indoles using (NH4)2S2O8 in dichloroethane at 80 °C. The efficiency of this catalytic approach was established by a broad scope of substrates involving quinones and hydroquinones to give high yields (61–93%) of 3-indolylquinones
通过在 80°C 下在二氯乙烷中使用 (NH 4 ) 2 S 2 O 8将醌/氢醌与吲哚直接氧化 C-C 偶联,成功实现了一种原子经济且环境友好的合成 3-吲哚基醌的方法。这种催化方法的效率取决于包括醌和氢醌在内的广泛底物,以提供高产率 (61-93%) 的 3-吲哚基醌。本协议简单、实用,并显示出良好的官能团耐受性。此外,对所得3-吲哚基萘醌类化合物进行进一步转化,分别合成了2-氨基-3-吲哚基萘醌类化合物和多环N-杂环化合物。
One-pot synthesis of indole-fused nitrogen heterocycles <i>via</i> the direct C(sp<sup>2</sup>)–H functionalization of naphthoquinones; accessibility for deep red emitting materials
作者:Subramaniyan Prasanna Kumari、Savarimuthu Philip Anthony、Subramaniapillai Selva Ganesan
DOI:10.1039/d2nj02024f
日期:——
A convenient one-pot, two-step methodology was developed for the transformation of readily available planar naphthoquinone derivatives into structurally complex indole-fused nitrogen heterocycles under aerobic conditions.
The usefulness of 3-iodoindoles available for introduction of an indole unit is presented. The reaction of various halo-3-iodoindoles with 1,4-naphthoquinone gave the corresponding 2-(3-indolyl)-1-4,naphthoquinones in moderate yields. The 3-iodoindole was used for synthesis of a compound containing both naph-thazarin and indole skeletons.