Synthesis of Supramolecular Iridium Catalysts and Their Use in Enantioselective Visible-Light-Induced Reactions

Iridium complexes were prepared which are covalently linked via a bipyridine ligand to a chiral octahydro-1H-4,7-methanoisoindol-1-one skeleton. The skeleton allows for two-point hydrogen bonding to prochiral lactams, which can be processed in iridium-catalyzed photochemical reactions. Attempts to use the iridium complexes in reactions, which typically involve photoinduced electron transfer, failed to provide the desired enantioselectivity. If employed as triplet sensitizers the complexes showed an improved performance and moderate enantioselectivities (up to 29% ee) were achieved in a photochemical epoxide rearrangement.