Synthesis of 3- and 4-substituted cyclic α-amino acids structurally related to ACPD

Abstract

The preparation of 3-substituted cyclopentanones 12-16, 4-substituted cyclohexanones 23–28 and cycloheptanones 38–41 is described. Substituents in the cycloalkanones are carboxylate, phosphonate or tetrazole groups, separated from the ring by a 0, 1, 2, or 3 carbon atoms chain. These cycloalkanones have been transformed into α-amino acids 9–11 by hydrolysis of the corresponding hydantoin derivatives 21, 37 and 62, obtained under Bucherer-Bergs reaction conditions.