Derivatives of α,β-methanovaline, α,β-methanophenylalanine and β-methyl-αβmethanoalanine have been prepared by regioselective side-chain functionalization of suitably protected amino acid derivatives, followed by cyclization with either sodium hydride or 1,8-diazabicyclo[5.4.O]undec-7-ene. The approach used in this work illustrates a method for the synthesis of cyclopropyl amino acid derivatives which is complementary to existing procedures.