Multicomponent Reactions Involving Carbon Dioxide (CO₂) and Isocyanides

The employment of the copious and renewable carbon dioxide (CO₂) as a C1 synthon in multicomponent reactions represents a revolutionary strategy for promoting sustainable synthesis and the valorization of carbon resources. This review comprehensively scrutinizes recent advancements in CO₂-involved multicomponent reactions with isocyanides, primarily focusing on two innovative methodologies: first, the strategic in situ generation of reactive carbonate intermediates from CO₂ in Ugi and Passerini reactions, which facilitates the efficient assembly of nitrogen-containing fine chemicals. Second, the transition-metal-catalyzed direct incorporation of CO₂ into isocyanides, enabling subsequent cyclization with o-haloanilines, alkynes, and other components to obtain privileged heterocyclic structures-such as quinazolinediones and phthalimides-and functional polymeric materials. These developments not only lay the fundamental mechanistic groundwork for CO₂ participation in amphiphilic reaction systems but also highlight its significant potential for the design of novel pharmacologically active agents and advanced functional materials.