Auwers synthesis
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Template:Reactionbox The Auwers synthesis is a series of organic reactions forming a flavonol from a coumarone. This reaction was first reported by Karl von Auwers in 1908.[1][2][3][4][5]
The first step in this procedure is an acid catalyzed aldol condensation between benzaldehyde and a 3-cyclooxapentanone to an o-hydroxychalcone. Bromination of the alkene group gives a dibromo-adduct which rearranges to the flavonol by reaction with potassium hydroxide.
Mechanism
A possible mechanism for the rearrangement step is shown below:
See also
References
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- ↑ K. Auwers, K. Müller, "Umwandlung von Benzal-cumaranonen in Flavonole", Ber. Dtsch. Chem. Ges., 41, 4233–4241 (1908) (Script error: No such module "doi".).
- ↑ K. v. Auwers, P. Pohl, "Über die Umwandlung von Benzalcumaranonen in Flavonole", Liebigs Ann. Chem., 405, 243–294 (1914) (Script error: No such module "doi".).
- ↑ K. v. Auwers, P. Pohl, "Eine Synthese des Fisetins", Ber. Dtsch. Chem. Ges., 48, 85–90 (1915) (Script error: No such module "doi".).
- ↑ K. v. Auwers, "Zur Bildung von Flavonolen aus Benzal-cumaranonen", Ber. Dtsch. Chem. Ges., 49, 809–819 (1916) (Script error: No such module "doi".).
- ↑ K. v. Auwers, E. Auffenberg, "Über Cumaranone und Hydrindone", Ber. Dtsch. Chem. Ges., 52, 92-113 (1919) (Script error: No such module "doi".).