Enantioselective organocatalytic addition of oxazolones to 1,1-bis(phenylsulfonyl)ethylene: a convenient asymmetric synthesis of quaternary alpha-amino acids.
Chemistry
; 16(18): 5354-61, 2010 May 10.
Article
em En
| MEDLINE
| ID: mdl-20209524
ABSTRACT
A new, easy, and highly enantioselective method for the synthesis of quaternary alpha-alkyl-alpha-amino acids based on organocatalysis is reported. The addition of oxazolones to 1,1-bis(phenylsulfonyl)ethylene is efficiently catalyzed by simple chiral bases or thioureas. The reaction affords alpha,alpha-disubstituted alpha-amino acid derivatives with complete C4 regioselectivity and with excellent yields and enantioselectivities. This methodology is complementary to previously reported enantioselective approaches to quaternary alpha-amino acids and allows the synthesis of alpha-phenyl-alpha-alkyl-alpha-amino acids and alpha-tert-butyl-alpha-alkyl-alpha-amino acids. It has distinct advantages in terms of operational simplicity, enviromentally friendly conditions, and suitability for large-scale reactions.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Solventes
/
Compostos de Sulfidrila
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Oxazolona
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Etilenos
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Aminoácidos
Idioma:
En
Ano de publicação:
2010
Tipo de documento:
Article