Catalytic Reactions of Terminal Alkynes Using Rhodium(I) Complexes Bearing 8-Quinolinolate Ligands

8-Quinolinolate is a monoanionic, hard, strongly σ-donating ligand and can form strong chelates with various metals. However, studies of the catalytic activities of soft transition metal complexes such as >2nd row, low-valent, late-transition metals having 8-quinolinolate ligands had not been well explored until recently. In recent years, several researchers including our group have studied and developed various reactions of terminal alkynes using rhodium(I) catalysts containing an 8-quinolinolate ligand. In this Perspective, we surveyed the transformations of terminal alkynes using 8-quinolinolato rhodium(I) catalyst such as additions of alcohols, amines, and thiols, as well as polymerization, trimerization, dimerization, and alkyne/alkene [2+2] cycloaddition. Mechanistic studies based on theoretical calculations of hydroalkoxylation of alkynes and alkyne/alkene [2+2] cycloaddition reactions have also been described.