Feist-Benary synthesis

The Feist-Benary synthesis is an organic reaction between α-halogen ketones and β-dicarbonyl compounds to substituted furan compounds. [cite journal
author = Franz Feist
title = Studien in der Furan- und Pyrrol-Gruppe
pages = 1537–1544
doi = 10.1002/cber.19020350263
journal = Chemische Berichte
year = 1902
volume = 35] [cite journal
author = Erich Benary
title = Synthese von Pyridin-Derivaten aus Dichlor-äther und β-Amino-crotonsäureester
pages = 489–493)
doi = 10.1002/cber.19110440175
journal = Chemische Berichte
year = 1911
volume = 44] This condensation reaction is catalyzed by amines such as ammonia and pyridine. The first step in the ring synthesis is related to the Knoevenagel condensation. In the second step the enolate displaces an alkyl halogen in a nucleophilic aliphatic substitution.

A recent modification is the enantioselective interrupted Feist-Benary reaction [cite journal
author = Calter, M. A.; Phillips, R. M.; Flaschenriem, C.
title = Catalytic, Asymmetric, "Interrupted" Feist-Bénary Reactions
journal = Journal of the American Chemical Society
year = 2005
volume = 127
issue = 42
pages = 14566–14567
doi = 10.1021/ja055752d] with a chiral auxiliary based on the cinchona alkaloid quinine based in the presence of proton sponge to the hydroxydihydrofuran. This type of alkaloids is also used in asymmetric synthesis in the AD-mix. The alkaloid is protonated throughout the reaction and transfers its chirality by interaction of the acidic ammonium hydrogen with the dicarbonyl group of ethyl bromopyruvate in a 5-membered transition state.

External links

* [http://www.wesleyan.edu/chem/faculty/calter/ Calter group]

References