Asymmetric Hydride Shift Reactions Catalyzed by Chiral Aluminium Complexes

Abstract An asymmetric intramolecular hydride shift reaction has been developed that is catalyzed by Al Lewis acids in conjunction with a chiral BINOL‐derived ligand. Racemic THP substrates are transformed into cyclohexene products via a prochiral intermediate ring opened enone; which then undergoes a key 1,5‐hydride shift reaction. This reaction is operationally simple, works well on a gram scale, and the desired products are formed with very high enantioselectivity (up to >98:2 e.r.). Importantly, the cyclohexene products contain functionality that can be easily derivatized and this is exemplified in the paper. Finally, a model is presented for the enantioselective hydride shift that is based on previous DFT studies.