Carbon-carbon cross coupling reactions assisted by Schiff base complexes of Palladium, cobalt and copper: A brief overview

Abstract

Carbon-carbon cross coupling reactions are extremely important organic transformations, but these are quite difficult to achieve without catalyst. Various types of catalysts have been designed to carry out these reactions. Initially phosphine-based ligands were involved but these are toxic and sensitive in nature. So, researchers have reverted to Schiff base (SB) ligands which were easy to synthesize, stable in nature and utilized in formation of variety of transition metal complexes. Schiff base ligands are generally synthesized from condensation reaction between an amino group and carbonyl compounds and their transition metal complexes are widely utilized in different CC cross coupling reactions. Palladium complexes are now well-known catalysts in carbon-carbon cross coupling reactions including Suzuki-Miyaura and Sonogashira cross coupling reactions. But researchers are also interested in other transition metal complexes. Hence this review is focused on the synthesis of Schiff base ligands, their complexation especially with Pd, Co and Cu and their application in CC cross coupling reactions.