Producción CyT

(+)- and (-)-2-Aminocyclobutane-1-carboxylic Acids and Their Incorporation into Highly Rigid beta-Peptides: Stereoselective Synthesis and a Structural Study

Artículo

Autoría:

Sandra Izquierdo ; RÚA, FEDERICO ; Teodor Parella ; Angel Alvarez-Larena ; Vicenç Branchadell ; Rosa María Ortuño

Fecha:

2005

Editorial y Lugar de Edición:

AMER CHEMICAL SOC

Revista:

JOURNAL OF ORGANIC CHEMISTRY, vol. 70 (pp. 7963-7971) AMER CHEMICAL SOC

Resumen *

Several derivatives of (+)- and (-)-2-aminocyclobutane-1-carboxylic acid, 1, have been prepared through enantiodivergent synthetic sequences. The stereoselective synthesis of free amino acid (+)-1 has been achieved, and this product has been fully characterized for the first time. Stereocontrolled alternative synthetic methodologies have been developed for the preparation of bis(cyclobutane) beta-dipeptides in high yields. Among them, enantio and diastereomers have been synthesized. Beta,beta- and beta,delta-Dimers resulting from the coupling of a cyclobutane residue and a linear amino acid have also been prepared. The ability of the cyclobutane ring as a structure-promoting unit both in the monomers and in the dimers has been manifested. The NMR structural study and DFT theoretical calculations evidence the formation of strong intramolecular hydrogen bonds giving rise to cis-fused [4.2.0]octane structural units that confer high rigidity on these molecules both in solution and in the gas phase. The contribution of a cis-trans conformational equilibrium derived from the rotation around the carbamate N-C(O) bond has also been observed, the trans form being the major conformer. In the solid state, this equilibrium does not exist, and moreover, intermolecular hydrogen bonds are present. Información suministrada por el agente en SIGEVA

Palabras Clave

BETA-PEPTIDEAMINOCYCLOBUTANESYNTHESISSTEREOSELECTIVE