Transition metal-guanidine complexes as catalysts in organic reactions. Recent developments

Abstract

Guanidines have received great attention due to their application as superbasic proton sponges and organocatalysts, as well as excellent N-donor ligands able to coordinate with different metals. The introduction of different substituents can modulate the basicity/nucleophilicity of the guanidines, their coordination ability, and thus, the electronic and steric properties of their metal complexes, regulating their catalytic activity. This review presents recent developments on guanidine-based ligand families [monoguanidine, bis(guanidine) and hybrid guanidine ligands], highlighting their potential in transition metalcatalyzed reactions.