Cyanohydrin formation
Cyanide addition to an aldehyde forms a hydroxynitrile, giving a carbonyl-route analogue of the nitrile chain-extension motif.
- Reagents
- HCN with KCN catalyst
- Conditions
- room temperature
- Reaction class
- nucleophilic addition
- Equation
- R-CHO + HCN -> R-CH(OH)-CN
Overview
Cyanide addition to an aldehyde forms a hydroxynitrile, giving a carbonyl-route analogue of the nitrile chain-extension motif.
Transformation
- Equation
- R-CHO + HCN -> R-CH(OH)-CN
- Reagents
- HCN with KCN catalyst
- Environment
- room temperature
- Reaction class
- nucleophilic addition
- Mechanism
- nucleophilic addition
- Evidence level
- textbook core
Scope and limitations
- Scope
- Aldehydes react with cyanide / hydrogen cyanide to form hydroxynitriles with one extra carbon.
- Limitations
- This route records the addition outcome; aldehyde and ketone cyanohydrin routes are separated because their substrate layouts differ.
Related reactions
- Cyanohydrin formation: Ketones → Hydroxynitriles
Cyanide addition to a ketone forms a hydroxynitrile, adding a second carbonyl route into the expanded organic network.
- Oxidation: Alcohols → Aldehydes
Controlled oxidation of a primary alcohol gives an aldehyde.
- Controlled oxidation: Primary alcohols → Aldehydes
Controlled oxidation of a primary alcohol gives an aldehyde.
- Reduction: Aldehydes → Primary alcohols
Reduction of an aldehyde gives a primary alcohol.
- Oxidation: Aldehydes → Carboxylic acids
Oxidation of an aldehyde gives a carboxylic acid.
- Grignard addition co reactant: Aldehydes → Secondary alcohols
Aldehydes plus Grignard reagents give secondary alcohols after acidic work-up.
References
- Organic Chemistry: Nucleophilic Addition of HCN: Cyanohydrin FormationJohn McMurry · OpenStax Organic Chemistry · 2023
Supports cyanide addition to aldehydes and unhindered ketones followed by protonation to form cyanohydrins / hydroxynitriles.