2012 Volume 60 Pages 24-31
In this review, haptotropic isomerizations and arene ligand exchange reactions of the tircarbonyl chromium complexes have been reported. Haptotropic metal migration reactions are well known phenomena for theπ-arene chromium complexes possessing the fused arene rings. Proper adjustment of the template allows for a photo induced reverse migration of the metal moiety, which can be utilized for the switchable organometallic device. Not only for the naphthalene chromium complex but also tri, tetra and pentacyclic fused system can be utilized for the reactions. Arene exchange reaction in arene chromium complex is also well known reaction. Basically, arene exchange reactions require high temperature (140-180 °C) in the presence of a large excess of the incoming arene. However, a couple of efforts to accelerate the ligand exchange have been developed. Basic concept for the acceleration is the design of a ligand to promote the formation of η4-intermediate which is one of late determined steps in this reaction. In recent years, chromium tricarbonyl group migration reaction can be utilized as a mobile chiral auxiliary for the stereoselective migration reactions.
