Asymmetric Direct Amide Synthesis by Kinetic Amine Resolution: A Chiral Bifunctional Aminoboronic Add Catalyzed Reaction between a Racemic Amine and an Achiral Carboxylic Acid

摘要

The formation of amide bonds by direct reaction of amines with carboxylic acids by thermal or catalytic methods is generally a high temperature process. There have been no reports to date of any reactions that involve asymmetric induction during direct amide formation, with the exception of an enzyme-catalyzed process. Lower temperatures are often preferred for any reaction as it can reduce the amount of reagent, reactant, or thermal product degradation. A more important consideration is that asymmetric induction processes are usually more efficient at lower temperatures because small differences in energy between diasteroisomeric transition states are amplified; however, there are an increasing number of examDles where this is not the case and improved asymmetric induction can be obtained at higher temperatures.