Recyclable and Stable <i>α</i>-Methylproline-Derived Chiral Ligands for the Chemical Dynamic Kinetic Resolution of free <i>C,N</i>-Unprotected <i>α</i>-Amino Acids

Abstract

A novel special designed, stable, and recyclable chiral ligand bearing a quaternary carbon was developed for chemical dynamic kinetic resolution (DKR) of free C,N-unprotected racemic α-amino acids via Schiff base intermediates. This method furnishes high yields with excellent enantioselectivity, has a broad substrate scope, and uses operationally simple and convenient conditions. The present chemical DKR is a practical and useful method for the preparation of enantiopure α-amino acids.

Keywords

• quaternary carbon
• dynamic kinetic resolution
• unprotected <i>α</i>-amino acids
• Schiff base intermediates
• ligands