Recent Progress in the Synthesis of Indolizine Derivatives

Abstract: Indolizines are N-bridgehead bicyclic heterocyclic compounds with a π-excessive pyrrole and a π-deficient pyridine. These heterocycles widely appear both in nature and in synthetic sources. This subclass of heterocycles possesses a diverse range of bioactivities, such as antimicrobial, anti-inflammatory, anticancer, antiviral, and enzyme inhibitory activities, and several synthetic compounds with an indolizine skeleton have been used as drugs for the treatment of various diseases. In addition, many indolizine derivatives have been employed as important building blocks for the synthesis of many bioactive and heterocyclic compounds. Applications of indolizines in organic materials have also been well documented. Due to the importance of indolizine-based compounds, the development of efficient methods for the synthesis of indolizine derivatives has attracted the attention of chemists, and a number of studies on the synthesis of indolizines have been reported over the years. In this review article, we will give a comprehensive overview of the synthesis of indolizines dating back to 2014. More than 145 studies on the synthesis of indolizine derivatives have been collected and summarized. References have been retrieved from various resources such as Google Scholar, SciFinder, and PubMed. The work might be useful for chemists who work in the synthesis of heterocycles and in medicinal chemistry.