Dynamic Kinetic Asymmetric Amination of Alcohols: From A Mixture of Four Isomers to Diastereo- and Enantiopure α-Branched Amines
摘要:
The first dynamic kinetic asymmetric amination of alcohols via borrowing hydrogen methodology is presented. Under the cooperative catalysis by an iridium complex and a chiral phosphoric acid, a-branched alcohols that exist as a mixture of four isomers undergo racemization by two orthogonal mechanisms and are converted to diastereo- and enantiopure amines bearing adjacent stereocenters. The preparation of diastereo- and enantiopure 1,2-amino alcohols is also realized using this catalytic system.
Ex‐changing places: A highlyenantioselectivedesymmetrization of 1,2‐diols has been developed in which the catalyst utilizes reversible covalent bonding to the substrate to achieve both high selectivity and rate acceleration (see scheme, PMP=pentalmethylpiperidine, TBS=tert‐butyldimethylsilyl). Induced intramolecularity is responsible for the enhanced rate, thus allowing the reaction to be performed at