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]
The acyloin condensation
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.
^Bouveault, L.; Locquin, R. (1905). "Action du sodium sur les éthers des acides monobasiques à fonction simple de la série grasse" [Effect of sodium on the ethers of single-function monobasic acids of the fatty series]. Compt. Rend. (in French). 140: 1593–1595.
^Finley, K. T. (1964). "The Acyloin Condensation as a Cyclization Method". Chem. Rev.64 (5): 573–589. doi:10.1021/cr60231a004.
^Bloomfield, J. J.; Owsley, D. C.; Nelke, J. M. Org. React.1976, 23.
and 23 Related for: Acyloin condensation information
Acyloincondensation is a reductive coupling of two carboxylic esters using impure metallic sodium to yield an α-hydroxyketone, also known as an acyloin...
results in formation of an acyloin. In the classic example, benzaldehyde is converted to benzoin. The benzoin condensation was first reported in 1832...
for the synthesis of acyloins. The acyloincondensation is a reductive coupling of esters The benzoin condensation is condensation reaction between aldehydes...
nitriles. Pairs of esters are coupled to give α-hydroxyketones in the acyloincondensation As a class, esters serve as protecting groups for carboxylic acids...
versatile building block. It participates in acyloincondensation to give 2-hydroxycyclobutanone. Via condensation with oxalate esters, it serves as a precursor...
elevated temperatures, while another uses acyloincondensation of the ethyl ester of pimelic acid the acyloin again followed by oxidation by bromine. An...
stereochemistry). These general reactions include: Acyloincondensation; Anodic oxidations; and the Dieckmann condensation as applied to ring formation. In organic...
appearing in reactions such as the final reduction step of the acyloincondensation. Benzil semidione (Ph−C(−O−)=C(−O•)−Ph), synthesized by Auguste Laurent...
compounds with 8 to 12 members from dicarboxylic acid esters by acyloincondensation and explained their unusual chemical reactivity by a "nonclassical"...
double bonds to single bonds. For example, sebacoin, derived from the acyloincondensation of dimethyl sebacate, is hydrogenated to 1,2-cyclodecanediol by this...
this reaction step the alkene group is first oxidized to an intermediate acyloin by action of osmium(III) chloride, oxone (sacrificial catalyst) and sodium...
that are enabled or enhanced intramolecularly. For example, the acyloincondensation of diesters almost uniquely produces 10-membered carbocycles, which...
R−C(=O)−CH2−C(OH)−R' (beta). Alpha-hydroxy ketones are also called acyloins. They are commonly formed by condensation or reductive coupling of two carbonyl (C=O) compounds...
of the reaction has been known to occur in many substrates bearing the acyloin functional group. The picture below shows the ring expansion of a cyclopentane...
compounds with various aromas. As such it finds some use as a flavoring. Acyloin, the simplest secondary α-hydroxy ketone. Nodzu, Ryuzaburo (1935). "On...
oxidation using m-chloroperbezoic acid to give the trimethylsilyl protected acyloin 30. At this stage the final missing carbon atom in the Taxol ring framework...
imidazol-2-ones involves condensation of ureas and acyloins. Some are of interest in the pharmaceuticals. 4-Imidazolones arise from the condensation of amidines with...
the hydrogenation of acyloins and the pinacol coupling reaction. 1,3-Diols are often prepared industrially by aldol condensation of ketones with formaldehyde...
cheaper oxidant. Alternatively, vicinal diols or their oxidized sequelae (acyloins or α-hydroxy acids) can be oxidized with cleavage to two aldehydes or an...
this starting material by enzymatic resolution of one of the precursors. Acyloin 2 was formed by Rubottom oxidation and hydrolysis. Oxidative cleavage by...
with formula C10H8O4. It can be produced from furfural by a benzoin condensation reaction catalyzed by cyanide ions. Furoin synthesis from furfural is...
organic reaction. Rather, it is intended to cover the basic reactions. In condensation reactions a small molecule, usually water, is split off when two reactants...
Global Information