Hydrogenation of Quinones to Hydroquinones under Atmospheric Pressure Catalyzed by a Metal–Ligand Bifunctional Iridium Catalyst

A general method for the hydrogenation of quinones to hydroquinones under atmospheric pressure has been developed. In the presence of [Cp*Ir(2,2′-bpyO)(H2O)] (0.5–1 mol %), a range of products were obtained in high yields. Furthemore, the expansion of this catalytic system to the hydrogenation of 1,4-benzoquinone diimines was also presented. Functional groups in the bpy ligand were found to be crucial for the catalytic activity of iridium complexes.