Asymmetric and efficient synthesis of homophenylalanine derivatives via Friedel–Crafts reaction with trifluoromethanesulfonic acid

An efficient Friedel–Crafts reaction of TFA-Asp(Cl)-OMe and stoichiometric amounts of benzene was established by using neat trifluoromethanesulfonic acid (TfOH) as solvent and catalyst under a mild condition. This methodology has been applied to many aromatic compounds and enabled synthesis of several homophenylalanine derivatives.