Unlocking the Potential of Deep Eutectic Solvents for C–H Activation and Cross-Coupling Reactions: A Review

Abstract

Green chemistry principles have underpinned the development of deep eutectic solvents (DESs). In this brief overview, we discuss the potential of DESs as a greener alternative to volatile organic solvents for cross-coupling and C–H activation reactions in organic chemistry. DESs offer numerous benefits, such as easy preparation, low toxicity, high biodegradability, and the potential to replace volatile organic compounds. The ability of DESs to recover the catalyst-solvent system enhances their sustainability. This review highlights recent advances and challenges in utilizing DESs as a reaction media, as well as the impact of physicochemical properties on the reaction process. Several types of reactions are studied to highlight their effectiveness at promoting C–C bond formation. Aside from demonstrating the success of DESs in this context, this review also discusses the limitations and future prospects of DESs in organic chemistry.

Diastereoselective multicomponent synthesis of dihydroisoindolo[2,1-a]quinolin-11-ones mediated by eutectic solvents

“… 5,6 A DES can be defined as a mixture, formed by two or more compounds, with the lowest melting temperature compared to its individual components. To date, these solvents have been classified considering their components: DES type I are formed from metal chlorides (MCl x ) and quaternary ammonium salts; type II are based on metal chloride hydrates and quaternary ammonium salts; hydrogen bond donors (HBD) and quaternary ammonium salts form the type III; HBD and metal chloride hydrates are the type IV and finally, mixtures of non-ionic compounds such as terpenes or terpenoids constitute the type V. 7 Notable applications of DES for the synthesis of heterocyclic compounds, 8 C–H activation, and cross-coupling reactions 9 have been recently reported in literature, and although several groups have made important contributions in these fields, the scope and limitations of these new and promising reaction media are still under study.…”