Asymmetric Synthesis of Quaternary α-Amino Acids and Their Phosphonate Analogues

Asymmetric synthesis of alpha-amino acids and their phosphonate analogues has received considerable attention due to their diverse biological activities. Quaternary alpha-amino acids and their phosphonate analogues are often more resistant to chemical and enzymatic degradation and therefore have been targets of various synthetic endeavors. This Focus Review provides a summary of recent approaches to catalytic asymmetric synthesis of quaternary alpha-amino acids and alpha-aminophosphonates.