Acyloin condensation
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Acyloin condensation is a reductive coupling of two carboxylic esters using impure metallic sodium to yield an α-hydroxyketone, also known as an acyloin.[1][2][3]
Acyloin condensation | |
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Reaction type | Coupling reaction |
Identifiers | |
Organic Chemistry Portal | acyloin-condensation |
RSC ontology ID | RXNO:0000085 |
The reaction is most successful when R is aliphatic and saturated, and typically performed with a silyl chloride reactant to trap the product as a disilyl enediol ether.
The reaction is performed in aprotic solvents with a high boiling point, such as benzene and toluene, in an oxygen-free atmosphere (as even traces of oxygen interfere with the reaction path and reduce the yield). Protic solvents effect the Bouveault-Blanc ester reduction rather than condensation.
Independent of dilution, acyloin condensation of a diester favours intramolecular cyclisation (for all but the smallest rings) over intermolecular polymerisation. This effect is believed to originate in weak adsorption of the ester terminals at nearby sites on the sodium metal.