Michael addition of chiral Fischer aminocarbene complexes to nitroolefins:Study on the effect of the Michael acceptor structure on diastereoselectivity

Citation
E. Licandro et al., Michael addition of chiral Fischer aminocarbene complexes to nitroolefins:Study on the effect of the Michael acceptor structure on diastereoselectivity, ORGANOMETAL, 20(3), 2001, pp. 485-496
Citations number
29
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
ORGANOMETALLICS
ISSN journal
0276-7333 → ACNP
Volume
20
Issue
3
Year of publication
2001
Pages
485 - 496
Database
ISI
SICI code
0276-7333(20010205)20:3<485:MAOCFA>2.0.ZU;2-W
Abstract
The anions of the pentacarbonyl(chromium) trans-2,6-dimethylmorpholinyl(met hyl)carbene and pentacarbonyl(chromium) trans-3,5-dimethylpiperidinyl(methy l)carbene complexes added to E- and Z-nitrostyrenes through a diastereosele ctive Michael-type reaction to give precursors of beta -aryl-gamma -butyric acid derivatives. The diastereoselectivity observed with the former carben e was dependent on the nature of the substituent present in the 4-position of nitrostyrenes and was higher when it was an electron-withdrawing group. The presence of 12-crown-4 ether in the reaction medium increased both reac tion times and diastereoselectivity. Theoretical calculations were performe d to rationalize the stereochemical outcomes of the reactions and to suppor t the proposed transition state models.