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An aldol condensation is a condensation reaction in organic chemistry in which two carbonyl moieties (of aldehydes or ketones) react to form a β-hydroxyaldehyde or β-hydroxyketone (an aldol reaction), and this is then followed by dehydration to give a conjugated enone. The overall reaction equation is as follows (where the Rs can be H)
(Benzylideneacetone)iron tricarbonyl is an organoiron compound with an η 2 ketone ligand. Some η 2-aldehyde complexes insert alkenes to give five-membered metallacycles. [5] η 1-Complexes of alpha-beta unsaturated carbonyls exhibit enhanced reactivity toward dienes. This interaction is the basis of Lewis-acid catalyzed Diels-Alder reactions.
In organic chemistry, aldol reactions are acid- or base-catalyzed reactions of aldehydes or ketones. Aldol addition or aldolization refers to the addition of an enolate or enolation as a nucleophile to a carbonyl moiety as an electrophile. This produces a β-hydroxyaldehyde or β-hydroxyketone.
formation of an enamine from a ketone; addition of the enamine to an alpha, beta-unsaturated aldehyde or ketone; hydrolysis of the enamine back to a ketone; The Stork enamine reaction. The reaction also applies to acyl halides as electrophiles, which results in the formation of 1,3-diketones (Stork acylation). [2]
The Buchner–Curtius–Schlotterbeck reaction is the reaction of aldehydes or ketones with aliphatic diazoalkanes to form homologated ketones. [1] It was first described by Eduard Buchner and Theodor Curtius in 1885 [ 2 ] and later by Fritz Schlotterbeck in 1907. [ 3 ]
Below, the reaction mechanism is shown with R 2 = H: Mukaiyama Aldol-MechanismusV7 en. In the cited example the Lewis acid TiCl 4 is used. First, the Lewis acid activates the aldehyde component followed by carbon-carbon bond formation between the enol silane and the activated aldehyde. With the loss of a chlorosilane the compound 1 is built.
The reaction sequence in many examples starts from conversion of a ketone into an enolate by action of lithium diisopropylamide (LDA), to which a suitable aldehyde is added. The resulting mono-ester diol is then converted into the diol by a hydrolysis step.
The McMurry reaction of benzophenone. The McMurry reaction is an organic reaction in which two ketone or aldehyde groups are coupled to form an alkene using a titanium chloride compound such as titanium(III) chloride and a reducing agent. The reaction is named after its co-discoverer, John E. McMurry.