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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.
Aldehyde structure. In organic chemistry, an aldehyde (/ ˈ æ l d ɪ h aɪ d /) is an organic compound containing a functional group with the structure R−CH=O. [1] The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl group.
The Norrish type I reaction is the photochemical cleavage or homolysis of aldehydes and ketones into two free radical intermediates (α-scission). The carbonyl group accepts a photon and is excited to a photochemical singlet state. Through intersystem crossing the triplet state can be obtained.
The aldol reaction (aldol addition) is a reaction in organic chemistry that combines two carbonyl compounds (e.g. aldehydes or ketones) to form a new β-hydroxy carbonyl compound. Its simplest form might involve the nucleophilic addition of an enolized ketone to another: Prototype aldol reaction
Aldol reactions may proceed by two distinct mechanisms. Carbonyl compounds, such as aldehydes and ketones, can be converted to enols or enol ethers. These species, being nucleophilic at the α-carbon, can attack especially reactive protonated carbonyls such as protonated aldehydes. This is the 'enol mechanism'.
Since, aldehydes reduce more easily than ketones, they require milder reagents and milder conditions. At the other extreme, carboxylic acids, amides, and esters are poorly electrophilic and require strong reducing agents. [17] The idealized equation for the reduction of a ketone by sodium borohydride is: 4 RCOR' + NaBH 4 → NaB(OCHRR') 4
Aldehydes are reduced before ketones allowing for a measure of control over the reaction. If it is necessary to reduce one carbonyl in the presence of another, the common carbonyl protecting groups may be employed. Groups, such as alkenes and alkynes, that normally pose a problem for reduction by other means have no reactivity under these ...
The Reformatsky reaction (sometimes transliterated as Reformatskii reaction) is an organic reaction which condenses aldehydes or ketones with α-halo esters using metallic zinc to form β-hydroxy-esters: [1] [2] The Reformatsky reaction. The organozinc reagent, also called a 'Reformatsky enolate', is prepared by treating an alpha-halo ester ...