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.