A practical asymmetric synthesis of α-methyl α-amino acids using a chiral Cu–salen complex as a phase transfer catalyst

The asymmetric C-alkylation of N-benzylidene alanine methyl ester has been achieved using a copper(II) (salen) complex as an asymmetric phase transfer catalyst and provides a practical synthesis of α-methyl α-amino acids with up to 86% enantiomeric excess.