Chapter 6 - Green Catalytic Synthesis of Heterocyclic Structures Using Carbon Dioxide and Related Motifs

Abstract

This chapter will focus on green and/or sustainable synthetic routes toward biologically relevant heterocyclic structures that incorporate carbon dioxide. This carbon source may be regarded as a renewable feedstock having a number of interesting features including cheapness, availability, and low toxicity. Current challenges for its conversion have driven contemporary chemists to design new and improved catalytic strategies that can address the need for cleaner production of a range of base chemicals using renewable sources. As such, consideration of the reaction between small heterocyclic structures such as aziridines and epoxides with carbon dioxide under appropriate reaction conditions may result in organic products with increased added value. These resultant oxazolidinones, 1,3-dioxolan-2-ones and related motifs, have found widespread application in industrial settings and have sparked the interest of many academic research groups. This chapter will first define the application areas of these organic synthons and will discuss the most important scaffolds reported to date. After this brief introduction, the focus will shift toward the various synthetic routes to these molecular building blocks, but principally address those that have an appealing sustainability fingerprint. Although the main focus will be on CO2-related processes, in some cases, a comparison is used to underline the importance of this carbon feedstock in relation to the depleting fossil-fuel-based raw materials. Also a section is presented that focuses on the different structures that are of potential interest for pharmaceutical development. Finally an outlook is provided describing the foreseen impact of the presented organic scaffolds, identifying the main current achievements and which challenges the chemical community is still facing to further increase the efficient use of carbon dioxide (and alike) as a key reagent in chemical processing.