Carbazole and Triarylpyrrole Synthesis from Anilines and Cyclohexanones or Acetophenones under Transition-Metal-Free Condition

Abstract

An efficient strategy for carbazoles and 1,2,4-triarylpyrroles synthesis from anilines and cyclohexanones or acetophenones under transition-metal-free conditions is developed. A variety of disubstituted 9-arylcarbazoles were synthesized in moderate to good yields promoted by KI/I using anilines as the nitrogen and aryl source. Meanwhile, a variety of 1,2,4-triarylpyrroles were also selectively synthesized from anilines and acetophenones in the presence of KI alone.

Progress in Selective Construction of Functional Aromatics with Cyclohexanone

“…反应以环己酮作为芳基源, 碘化钾和单质碘为添加剂, 对甲苯磺酸提供酸性环境, 氧气氛围下, 甲苯作溶剂, 160 ℃下反应(Scheme 21). 随后不久, 邓国军课题组 [53] 吲哚杂环芳烃是苯与吡咯并联的化合物, 又称苯并 吡咯, 具有弱碱性, 其同系物和衍生物广泛存在于自然 界天然花油中 [54][55][56] . 吲哚杂环的构建方法多种多样, 其 中通过环己酮缩合、脱氢芳构化来实现吲哚杂环的构建 是最常用的方法之一.…”

A Critical Review on Advances in the Multicomponent Synthesis of Pyrroles

“…In this context, Wu et al, recently proposed a one-pot synthesis of functionalized pyrrole derivatives, 2,6-disubstituted 9-arylcarbazoles 160 and 1,2,4-triaryl-substituted pyrroles 162 (Scheme 33). 107 The repor ted experimental procedure, utilized commercially available low-cost reactant, anilines 155 and cyclohexanones 159 in metal-free conditions leading to the formation of 2,6-disubstituted 9-arylcarbazoles 160 in high yields. For the synthesis of 1,2,4-triaryl-substituted pyrroles 162, acetophenones 161 were used in place of cyclohexanones 159.…”

Metal-Free Synthesis and Photophysical Properties of 1,2,4-Triarylpyrroles

“…In 2012, the direct synthesis of 1,3,4-triarylpyrroles with various substituted groups by ZnCl 2 -catalyzed cyclization of α-amino carbonyl compounds and aldehydes was reported . Recently, our group developed highly efficient methods for pyrrole formation through a three-component assembly of cyclohexanones, anilines, and ( E )-(2-nitrovinyl)­benzenes and annulations of anilines and acetophenones . In 1953, Grob and co-workers described pyrrole synthesis through a formal cycloaddition of nitro-olefins to enamine intermediates abtained in situ from 1,3-diketones .…”