Regioselective Hydrogenation of Polycyclic Aromatic Hydrocarbons and Olefins Catalyzed by Magnesium‐Activated Chromium Complexes

Abstract Replacing precious metals with the first‐row transition metals having abundant earth reserves in organic synthesis is in line with the sustainable development of chemistry. In this study, the regioselective hydrogenation of polycyclic aromatic hydrocarbons (PAHs) and olefins had been simply realized with a low‐valent Cr‐catalyst from CrCl 2 and diketimine, which was in situ reduced by magnesium. Results showed that unilateral cyclic hydrogenation of many PAHs could be achieved with this catalyst under mild conditions, which was a convenient and efficient method for the synthesis of partially saturated polycyclic aromatic hydrocarbons.