Transition-Metal-Free Synthesis of N-Heterocyclic Compounds via Multi-Component Reactions

Multicomponent reactions (MCRs) have emerged as powerful tools in synthetic chemistry for the efficient synthesis of diverse molecular scaffolds, particularly nitrogen-containing heterocycles. Despite their numerous advantages, the use of transition metal catalysts or additives in MCRs can present limitations due to cost, toxicity, and environmental concerns. In recent years, there has been a growing interest in transition metal-free MCRs for the synthesis of N-heterocyclic compounds. This review provides a comprehensive and concise overview of the recent advancements in transition metal-free MCRs for the synthesis of valuable N-heterocycles over the past five years. The review is systematically organized, categorizing the discussed MCRs based on the size of the heterocyclic ring and the number of nitrogen atoms. Only MCRs that result in the formation of heterocyclic rings containing at least one nitrogen atom are included, while the derivatization of N-heterocycles using transition metal-free MCRs falls outside the scope of this review. By highlighting the recent developments in this field, this review aims to showcase the potential and significance of transition metal-free MCRs as sustainable and efficient strategies for accessing N-heterocyclic compounds. The elimination of transition metals not only simplifies the reaction conditions but also contributes to greener and more environmentally friendly synthetic approaches. This review serves as a valuable resource for researchers interested in the design and application of transition metal-free MCRs in the synthesis of nitrogen-containing heterocycles.

Automated summary

Multicomponent reactions (MCRs) are powerful tools in synthetic chemistry for efficiently synthesizing diverse molecular scaffolds, particularly nitrogen-containing heterocycles. However, the use of transition metal catalysts or additives in MCRs can have limitations due to cost, toxicity, and environmental concerns. This review focuses on recent advancements in transition metal-free MCRs for synthesizing valuable N-heterocyclic compounds and highlights their potential as sustainable and efficient strategies for accessing nitrogen-containing heterocycles.