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In an aldol condensation, water is subsequently eliminated and an α,β-unsaturated carbonyl is formed. The aldol cleavage or Retro-aldol reaction is the reverse reaction into the starting compounds. The name aldehyde-alcohol reaction derives from the reaction product in the case of a reaction among aldehydes, a β-hydroxy aldehyde.
Alcohol oxidation is a collection of oxidation reactions in organic chemistry that convert alcohols to aldehydes, ketones, carboxylic acids, and esters. The reaction mainly applies to primary and secondary alcohols. Secondary alcohols form ketones, while primary alcohols form aldehydes or carboxylic acids. [1] A variety of oxidants can be used.
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)
The use of aldehyde in the name comes from its history: aldehydes are more reactive than ketones, so that the reaction was discovered first with them. [2] [3] [4] The aldol reaction is paradigmatic in organic chemistry and one of the most common means of forming carbon–carbon bonds in organic chemistry.
The direct oxidation of primary alcohols to carboxylic acids normally proceeds via the corresponding aldehyde, which is transformed via an aldehyde hydrate (R−CH(OH) 2) by reaction with water before it can be further oxidized to the carboxylic acid. Mechanism of oxidation of primary alcohols to carboxylic acids via aldehydes and aldehyde hydrates
Under acidic conditions, the hemiacetal and the alcohol can further react to form an acetal and water. Simple hemiacetals are usually unstable, although cyclic ones such as glucose can be stable. Acetals are stable, but revert to the aldehyde in the presence of acid. Aldehydes can react with water to form hydrates, R−CH(OH) 2.
Hemiacetals form in the reaction between alcohols and aldehydes or ketones. Using an acid catalyst, the reaction proceeds via nucleophilic attack of the carbonyl group by the alcohol. [4] A subsequent nucleophilic attack of the hemiacetal by the alcohol results in an acetal. [2] Solutions of simple aldehydes in alcohols mainly consist of the ...
Geminal diols can be viewed as ketone (or aldehyde) hydrates. The two hydroxyl groups in a geminal diol are easily converted to a carbonyl or keto group C=O by loss of one water molecule. Conversely, a keto group can combine with water to form the geminal hydroxyl groups. The equilibrium in water solution may be shifted towards either compound.