Cyclopeptoids as Phase‐Transfer Catalysts for the Enantioselective Synthesis of α‐Amino Acids

The first application of cyclopeptoids in asymmetric phase-transfer catalysis was examined. A small library of nine alternating N-substituted-glycine and proline hexacyclopeptoids was tested in the enantioselective alkylation of N-(diphenylmethylene)glycine tert-butyl ester. The presence of an N-arylmethyl side chain in the catalyst was found to be crucial for the synthesis of α-amino acids with up to 73 % ee.