A Concise beta-Lactam Route to Short Peptide Segments Containing beta,beta-Disubstituted beta-Amino Acids.
An efficient epimerization-free route toward beta,beta-disubstituted beta-amino acid-containing peptides is described. The methodology involves the use of 4,4-disubstituted-N-Boc beta-lactams as acylating agents, which upon coupling with amino acid esters, promoted by potassium cyanide, give rise to dipeptides with no appreciable racemization. By this procedure short peptide segments containing a four-, five-, or six-membered ring at the beta-position of the beta-amino acid residue have been prepared. The method has also proven to be valuable for the preparation of tripeptides. In addition the sterically hindered amino terminus of the beta-amino acid can undergo peptide couplings under standard conditions.
Palomo
Claudio
C
Departamento de Química Orgánica, Facultad de Química, Universidad del País Vasco, Apdo 1072, 20080 San Sebastián, Spain.
Oiarbide
Mikel
M
Bindi
Simona
S