A new route to fullerene substituted phenylalanine derivatives

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, H(2)NC(6)H(4)CH(2)CH(COR(1))(NHCOR(2))(where R(1) = OMe, R(2) = Me; R(1) = OH, R(2) = Me, O(t)Bu). Conversion of the imine to the corresponding amine is achieved by di-acid catalyzed hydroboration. Reaction of the N-Ac amino ester with BBr(3) led to the formation of the parent amino acid, while the Boc-protected derivative readily undergoes coupling with NH(2)-Gly-OEt. The reduction of the imine is not accompanied by hydroboration of the fullerene cage.