Enantioselective intramolecular michael addition of nitronates onto conjugated esters: access to cyclic gamma-amino acids with up to three stereocenters.
J Am Chem Soc
; 131(44): 16016-7, 2009 Nov 11.
Article
en En
| MEDLINE
| ID: mdl-19827809
ABSTRACT
A highly stereoselective synthesis of conformationally constrained cyclic gamma-amino acids has been devised. The key step involves an intramolecular cyclization of a nitronate onto a conjugated ester, promoted by a bifunctional thiourea catalyst. This methodology has been successfully applied to generate a variety of gamma-amino acids, including some containing three contiguous stereocenters, with very high diastereoselectivity and excellent enantioselectivity. It is postulated that an interaction that is key to the success of the process is the simultaneous coordination of the thiourea functionality to both the conjugated ester and the nitronate. Finally, the synthetic utility of these compounds is demonstrated in the synthesis of two dipeptides derived from the C- and N-termini.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Aminoácidos Cíclicos
/
Óxidos de Nitrógeno
Idioma:
En
Revista:
J Am Chem Soc
Año:
2009
Tipo del documento:
Article
País de afiliación:
Reino Unido