Cu(II)‐Catalyzed [3+2]‐Annulation of 2‐Pyridinyl‐substituted p‐Quinone Methides with Enaminones: Access to Functionalized Indolizine Derivatives

Abstract

This article describes an effective and atom‐economical protocol to access a wide range of synthetically important functionalized indolizine derivatives. This transformation basically takes place through a Cu(II) catalyzed formal [3+2] annulation of 2‐pyridinyl substituted p‐quinone methides with enaminones. This method displayed an excellent functional group tolerance and, was found to be very efficient for most of the enaminones and p‐QMs, and the corresponding indolizines were obtained in moderate to excellent yields.

Efficient Solvent-Free Synthesis of Indolizines Using CuBr Catalyst from Pyridine, Acetophenone, and Electron-Deficient Alkenes

“…In medicinal chemistry, indolizine derivatives have been found to exhibit significant biological activities, including anti-inflammatory, antimicrobial, antiviral, and anticancer properties [6]. This has led to a surge in research interest in this compound, with scientists seeking to understand its mechanisms of action and to develop new, more effective indolizine-based drugs [7][8][9]. In the field of materials science, indolizine has been studied for its potential use in the development of organic semiconductors and photovoltaic materials [10][11][12].…”

A HMPA–H2O mediated oxygenative carbocyclization of 2-alkynylphenyl-substituted p-quinone methides to indenones

“…In recent years, the synthetic utilities of p -quinone methides ( p -QMs) have been widely explored. 10 Our group was also involved in the synthesis of various triarylmethanes, 11 carbocycles 12 and heterocycles 13 using p -QMs as synthons. Herein, we report a transition-metal and base-free HMPA-mediated oxygenative carbocyclization of 2-alkynylated p -QMs 14 to access substituted indenones ( d , Scheme 1).…”