Reaction 2: Synthesis of the Five-Membered Cyclic Carbonates from Epoxides and CO2

Recently, CO2 xation has received much attention because CO2 is the most inexpensive and renewable carbon resource from the viewpoint of green chemistry.1 The development of a truly environmentally friendly process utilizing CO2, which is the largest single source of greenhouse gas and can be also regarded as a typical renewable natural resource, has drawn current interest in organic synthetic chemistry from the viewpoint of environmental protection and resource utilization. Chemical xation of CO2 onto industrial useful materials is one of the most promising methods because there are many possibilities for CO2 to be used as a safe and cheap C1 building block in organic synthesis.2 Organic cyclic carbonates such as ethylene carbonate and propylene carbonate are widely used for various purposes, for instance, electrolytic elements of lithium secondary batteries, polar aprotic solvents, monomers for synthesizing polycarbonates, and chemical ingredients for preparing medicines or agricultural chemicals.3