Phase-Transfer-Catalyzed Asymmetric SNAr Reaction of α-Amino Acid Derivatives with Arene Chromium Complexes

Although phase-transfer-catalyzed asymmetric SNAr reactions provide unique contribution to the catalytic asymmetric alpha-arylations of carbonyl compounds to produce biologically active alpha-aryl carbonyl compounds, the electrophiles were limited to arenes bearing strong electron-with-drawing groups, such as a nitro group. To overcome this limitation, we examined the asymmetric SNAr reactions of alpha-amino acid derivatives with arene chromium complexes derived from fluoroarenes, including those containing electron-donating substituents. The arylation was efficiently promoted by binaphthyl-modified chiral phase-transfer catalysts to give the corresponding alpha, alpha-disubstituted alpha-amino acids containing various aromatic substituents with high enantioselectivities.