Dynamic kinetic resolution (DKR) was demonstrated in the carbodiimide-mediated couplings of N-benzoyl-DLamino acids with L-amino acid esters: the yields of the D-L-peptides significantly exceeded 50% in some cases. NBenzoyl- DL-t-leucine afforded the D-L-peptide almost exclusively (up to 96% yield) in the reaction with methyl Lprolinate, which is the most efficient DKR obtained in the field of amino acids and derivatives.
Keywords: Dynamic kinetic resolution (DKR), carbodiimide-mediated couplings, N-benzoyl-DL-amino acids, 5(4H)-oxazolones