Ionic liquids (ILs) are of sustained interest in synthetic organic chemistry
due to their unique properties. The unique properties involve high thermal stability and
ionic conductivity, and tunable solvation properties due to tunable cationic and anionic
counterparts. There are a variety of cross-coupling reactions present in organic
chemistry, which facilitate new carbon-carbon and carbon-heteroatom bond formation.
Ionic liquids play various crucial roles in cross-coupling reactions. First, ILs are a
greener alternative to flammable and hazardous volatile organic solvents (VOCs).
Second, ILs are used as co-solvent in cross-coupling reactions to enhance the solubility
of organometallic reagents. Third, ILs are used as the precursors of N-heterocyclic
carbene (NHC) ligands that find their excellent utility in homogenous catalysis. The
NHCs are an excellent alternative to air-sensitive tertiary phosphine ligands and serve
as ligands for several palladium-catalyzed cross-coupling reactions. Apart from this,
ILs are exploited as additives to stabilize palladium nanoparticles (Pd-NPs) in many
cross-coupling reactions. This chapter outlines recent progress in key metal-catalyzed
cross-coupling reactions, employing ionic liquids in diverse capacities.
Keywords: Cross-coupling reactions, Green solvents, Ionic liquids, Metalcatalyzed reactions, Synthetic organic chemistry.
