Cyanation
Cyanide substitution forms a nitrile and extends the carbon chain by one carbon.
- Reagents
- KCN or NaCN
- Conditions
- ethanol, reflux
- Reaction class
- nucleophilic substitution
- Equation
- R-Br + CN- -> R-CN + Br-
Overview
Cyanide substitution forms a nitrile and extends the carbon chain by one carbon.
Transformation
- Equation
- R-Br + CN- -> R-CN + Br-
- Reagents
- KCN or NaCN
- Environment
- ethanol, reflux
- Reaction class
- nucleophilic substitution
- Mechanism
- nucleophilic substitution
- Evidence level
- textbook core
Scope and limitations
- Scope
- Cyanide substitution of bromoalkanes; the carbon chain increases by one carbon.
- Limitations
- Cyanide reagents are hazardous; carbon attack gives nitriles under the scoped conditions. Other cyanide sources can favour different products and belong to separate routes.
Related reactions
- Bromination: Alcohols → Bromoalkanes
Bromide and acid conditions convert alcohols into bromoalkanes.
- Hydrobromination: Alkenes → Bromoalkanes
Addition of hydrogen bromide across an alkene can form a bromoalkane.
- Cyanation: Chloroalkanes → Nitriles
Cyanide substitution forms a nitrile and extends the carbon chain by one carbon.
- Cyanation: Iodoalkanes → Nitriles
Cyanide substitution forms a nitrile and extends the carbon chain by one carbon.
- Amination: Bromoalkanes → Amines
Ammonia substitutes bromide to form a primary amine; excess ammonia limits further alkylation.
- Hydrolysis: Bromoalkanes → Alcohols
The C-Br bond can be displaced by hydroxide to form an alcohol.
- Elimination: Bromoalkanes → Alkenes
Base-promoted elimination removes HBr to form an alkene.
- Hydrolysis: Nitriles → Carboxylic acids
Nitriles can be hydrolysed to carboxylic acids, splitting the old aggregate nitrile-to-amide route into a single functional-group conversion.
- Reduction: Nitriles → Amines
Nitriles can be reduced to primary amines, separating the amine feedstock route from later amide or materials chemistry.
- Free radical bromination: Alkanes → Bromoalkanes
Photochemical bromination can convert alkanes into bromoalkanes.
- Grignard formation: Bromoalkanes → Grignard reagents
Bromoalkanes can react with magnesium in dry ether to form Grignard reagents.
References
- Pearson Edexcel Level 3 Advanced GCE in Chemistry specificationPearson Education Limited · Pearson qualifications · 2024
Supports the textbook-core organic reaction routes used for displayed route and mechanism content.