3-Aminocarboxylic acids (β-amino acids) are important products which are contained in naturally occurring peptides and are important chiral structural units for the synthesis of β-lactam antibiotics, and also for other pharmaceutically active substances, e.g. anti-platelet agents (see, for example, Zablocki et al., J Med. Chem. 36, 1811 (1993), Bovy et al., Bioorg. Med. Chem. 2, 881–895 (1994), Zablocki et al., J. Med. Chem.,38, 2378, U.S. Pat. No. 5,424,334 and U.S. Pat. No. 5,481,021), immunomodulating compounds (see, for example, Suda et al., J. Antibiotics 29, 100 (1976)), hypotensive agents (see, for example, Chaturvedi et al., J. Med. Chem. 13, 177 (1970), Lizuk et al., J. Chem. Soc. Chem. Commun. 1989, 1978, and Okino et al., Tetrahedron Lett. 34, 501 (1993)), or anticancer agents (see, for example, Denis et al., J. Org. Chem. 55, 1957 (1990)).
The object of the present invention is the provision of a process which makes possible the preparation of optically active 3-aminocarboxylic acid derivatives in a particularly advantageous manner, in particular in high optical purity and/or high yields.