Kinetic Resolution of Racemic Carboxylic Acids by an l-Histidine-Derived Sulfonamide-Induced Enantio
June 29th, 2008 | by admin |Kinetic Resolution of Racemic Carboxylic Acids by an l-Histidine-Derived Sulfonamide-Induced Enantioselective Esterification Reaction.
The direct and catalytic kinetic resolution of racemic carboxylic acids bearing a Brønsted base such as O-protected alpha-hydroxy carboxylic acids and N-protected alpha-amino acids has been accomplished through an l-histidine-derived sulfonamide-induced enantioselective esterification reaction with tert-butyl alcohol for the first time. Highly asymmetric induction [ S( k fast/ k slow) = up to 56] has been achieved under the equilibrium between a chiral catalyst and two diastereomeric acylammonium salts through an intramolecular hydrogen-bonding interaction.
Ishihara K, Kosugi Y, Umemura S, Sakakura A.