Carbanion stabilization by distal silyloxy groups. Origin of the high diastereoselectivity in the formation of quaternary centers with aryllead(IV) triacetate reagents.
Org Lett
; 4(23): 4121-4, 2002 Nov 14.
Article
em En
| MEDLINE
| ID: mdl-12423101
ABSTRACT
Derivatives of methyl 5-hydroxy-2-oxo-1-cyclohexanecarboxylate react with aryllead(IV) reagents in high yield and with wide variation in diastereoselectivity. Ab initio calculations are consistent with a heretofore unrecognized attraction between the carbanionic center of the beta-ketoester intermediate and the distal OSiR(3) group. This attractive interaction stabilizes the silyl group in the axial conformation and leads to the excellent trans diastereoselection in the formation of quaternary centers. [reaction see text]
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article