A new route to fullerene substituted phenylalanine derivatives

Abstract

A series of fullerene substituted phenylalanine derivatives have been prepared by the condensation of 1,2-(4′-oxocyclohexano)fullerene with ester or Boc protected (4-amino)phenylalanine, H₂NC₆H₄CH₂CH(COR₁)(NHCOR₂) (where R₁ = OMe, R₂ = Me; R₁ = OH, R₂ = Me, O^tBu). Conversion of the imine to the corresponding amine is achieved by di-acid catalyzed hydroboration. Reaction of the N-Ac amino ester with BBr₃ led to the formation of the parent amino acid, while the Boc-protected derivative readily undergoes coupling with NH₂–Gly–OEt. The reduction of the imine is not accompanied by hydroboration of the fullerene cage.