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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
In organic chemistry, the Schmidt reaction is an organic reaction in which an azide reacts with a carbonyl derivative, usually an aldehyde, ketone, or carboxylic acid, under acidic conditions to give an amine or amide, with expulsion of nitrogen.
The Wolff–Kishner reduction is a reaction used in organic chemistry to convert carbonyl functionalities into methylene groups. [1] [2] In the context of complex molecule synthesis, it is most frequently employed to remove a carbonyl group after it has served its synthetic purpose of activating an intermediate in a preceding step.
The imine is then reduced to an amine by sodium cyanoborohydride. This reaction works on both aldehydes and ketones. The carbonyl can be treated with ammonia, a primary amine, or a secondary amine to produce, respectively, 1°, 2°, and 3° amines. [5] Aromatic ketones and aldehydes can be reductively deoxygenated using sodium cyanoborohydride. [6]
Esters, amides: Reduction of an ester with diisobutylaluminium hydride or sodium aluminium hydride; see also amide reduction. Rosenmund reaction: Acyl chlorides: Acyl chlorides selectively reduced to aldehydes. Lithium tri-t-butoxyaluminium hydride (LiAlH(O t Bu) 3) is an effective reagent. [citation needed] Wittig reaction: Ketones
On the other hand, amides are much stronger bases than carboxylic acids, esters, aldehydes, and ketones (their conjugate acids' pK a s are between −6 and −10). The proton of a primary or secondary amide does not dissociate readily; its p K a is usually well above 15.
Many types of carbonyl compounds, including aldehydes, ketones, esters, thioesters, carboxylic acids, and amides, can be converted into enolate ions by reaction with LDA. Note that nitriles, too, are acidic and can be converted into enolate-like anions (referred to as nitrile anions).
Nahm and Weinreb also reported the synthesis of aldehydes by reduction of the amide with an excess of lithium aluminum hydride (see amide reduction). The Weinreb–Nahm ketone synthesis. The major advantage of this method over addition of organometallic reagents to more typical acyl compounds is that it avoids the common problem of over ...