Kinetic Resolution of Planar-Chiral (η~6-Arene)Chromium Complexes by Molybdenum-Catalyzed Asymmetric Ring-Closing Metathesis

摘要

Planar-chiral (η~+-arene)chromium complexes are useful chiral scaffolds in asymmetric synthesis, and have found widespread application as chiral ligands for asymmetric catalysis, or as chiral building blocks for natural product syntheses. Typical methods for the preparation of enantiomerically enriched planar-chiral (arene)chromium species are based either on the optical resolution of racemates or on stereoselective transformations, which include diastereoselective complex-ation, diastereo- or enantioselective ortho-lithiation by utilizing a chiral directing group or a chiral base, and diastereo- or enantioselective nucleophilic addition/hydride abstraction.