Palladium-Catalyzed α-Arylation of Azlactones to Form Quaternary Amino Acid Derivatives

The synthesis of α-aryl-α-alkyl amino acid derivatives from α-amino acids by the arylation of azlactone derivatives is reported. Arylation of
azlactones derived from alanine, valine, phenalanine, phenyl glycine, and leucine all provided good yields of the arylated product. Mechanistic
studies of this reaction revealed that a stable complex containing a ligand formed by reaction of dba with the azlactone accounts for a new
inhibiting effect of dba when reactions are initiated with Pd(dba)2.