Conjugate addition reactions of N-carbamoyl-4-pyridones and 2,3-dihydropyridones with Grignard reagents in the absence of Cu(I) salts.
J Org Chem
; 78(17): 8451-64, 2013 Sep 06.
Article
em En
| MEDLINE
| ID: mdl-23937057
ABSTRACT
N-Boc- and N-ethoxycarbonyl-4-pyridones and the resulting 2,3-dihydropyridones undergo 1,4-addition reactions with Grignard reagents in the presence of chlorotrimethylsilane (TMSCl) or BF3·Et2O in excellent yields. Copper catalysis is not required, and mechanistic considerations suggest that the reaction is proceeding by a conjugate addition pathway rather than by a pathway involving 1,2-addition to an intermediate pyridinium ion. TMSCl-mediated conjugate addition of Grignard reagents to 2-substituted-2,3-dihydropyridones gives the trans-2,6-disubstitued piperidinones stereoselectively, while cuprate reagents give either the trans or cis diastereomers or mixtures.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Compostos Organometálicos
/
Piperidinas
/
Piridonas
Idioma:
En
Revista:
J Org Chem
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Estados Unidos