Transition metal catalyzed Glaser and Glaser-Hay coupling reactions: Scope, classical/green methodologies and synthetic applications

Glaser coupling is one of the most important modern organic tool for the formation of carbon-carbon triple bond and has also been extensively used for the synthesis of polymers, macrocycles and oligomers (known for their electrochemical, optical and electronic properties). Although this reaction is generally catalyzed by copper complexes yet recent advances including new ligands, additives and silver/cobalt/palladium catalysts make this coupling reaction more effective. This review highlights the role of various catalytic systems used in Glaser- and Glaser-Hay coupling reactions for the production of a variety of C-C triple bonds with wide structural features.