Transforming natural amino acids into α-alkyl-substituted amino acids with the help of the HOF·CH₃CN complex

(Chemical Equation Presented) α-Alkyl amino acids can be efficiently prepared in high yields from the respective amino acids themselves. The key step is the oxidation of the amine function to create the corresponding α-nitro acid in a fast and very high yield reaction followed by phase-transfer alkylation and finally reduction to the desired α-alkyl amino acid. Several such acids containing aromatic rings or additional carboxylic groups and acids with steric hindrance at the α-position are suitable substrates. Several alkyl halides were examined as alkylating agents.