Enantioselective syntheses of homophenylalanine derivatives via nitrone 1,3-dipolar cycloaddition reactions with styrenes

A new two-step route to derivatives of homophenylalanine is presented. Cycloaddition of a cyclic nitrone glycine template with various styrene derivatives affords good yields of 5-substituted cycloadducts. One-step hydrogenolysis (three bonds) then affords the optically pure α-amino acids related to homophenylalanine.