ß-amino esters from the reductive ring opening of aziridine-2-carboxylates.
J Org Chem
; 79(21): 10068-80, 2014 Nov 07.
Article
em En
| MEDLINE
| ID: mdl-25329528
A general study is undertaken to examine the scope of the reductive ring opening of aziridine-2-carboxylates with samarium diiodide. The competition between C-C and C-N bond cleavage is examined as a function of the nature of the N-substituent of the aziridine, the nature of the substituent in the 3-position of the aziridine, and whether the substituent in the 3-position is in a cis or trans relationship with the carboxylate in the 2-position. The desired C-N bond cleavage leads to ß-amino esters that are the predominant products for most aziridines with an N-activating group. However, C-C cleavage products are observed with an aryl group in the 3-position; this can be particularly pronounced with cis-aziridines where a nearly equal mixture of the two is observed. Exclusive formation of the C-N cleavage product is observed for all aziridines with the strongly N-activating p-toluene sulfonate group. Similarly high selectivity is observed for the 2-trimethylsilylethyl sulfonate group (SES), which is easier to remove. The utility of these methods is illustrated in the synthesis of protected forms of (R)-ß(3)-DOPA and L-DOPA from the same aziridine, the former by SmI2-mediated reductive opening at C-2 and the latter by palladium-mediated reductive opening at C-3.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Aziridinas
Idioma:
En
Revista:
J Org Chem
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Estados Unidos