Carbon Dioxide in Heterocyclic Synthesis

As an abundant, nontoxic, nonflammable, easily available, and renewable carbon resource, carbon dioxide is very attractive as an environmentally friendly feedstock for making commodity chemicals, fuels, and materials. Owing to its kinetic and thermodynamic stability, significant efforts have been directed towards constructing C-C, C-O and C-N bond on the basis of CO2 activation through molecular catalysis. Development of catalytic methodologies for chemical transformation of CO2 into useful compounds is of paramount importance from a standpoint of C1 chemistry and green chemistry. The aim of this review is to demonstrate the versatile use of CO2 in heterocyclic synthesis, with the main focus on utilization of CO2 as a building block for synthesis of five- and six-membered heterocyclic compounds such as cyclic carbonates, oxazolidinones, imidazolidinones, lactones, quinazolines, etc. The potential use of dense CO2 as an alternative solvent and otherwise specific roles in the heterocyclic synthesis are also evaluated. We hope this presentation will stimulate further interest in research that may pave the way for selective synthesis of heterocycles employing CO2 as a synthon.