Carbonyl reduction
Hydride adds to the aldehyde carbon and the carbonyl oxygen becomes an alkoxide. Protonation completes the return to butan-1-ol.
- Reagents
- NaBH4; aqueous work-up
- Conditions
- Suitable alcohol solvent followed by protonation
- Reaction class
- Carbonyl reduction
- Equation
- CH3CH2CH2CHO + 2[H] -> CH3CH2CH2CH2OH
Overview
Hydride adds to the aldehyde carbon and the carbonyl oxygen becomes an alkoxide. Protonation completes the return to butan-1-ol.
Transformation
- Equation
- CH3CH2CH2CHO + 2[H] -> CH3CH2CH2CH2OH
- Reagents
- NaBH4; aqueous work-up
- Environment
- Suitable alcohol solvent followed by protonation
- Reaction class
- Carbonyl reduction
- Mechanism
- nucleophilic hydride addition
- Evidence level
- source-backed molecular example
Scope and limitations
- Scope
- Aldehyde reduction retains the straight four-carbon skeleton.
- Limitations
- [H] denotes reducing equivalents.
Related reactions
- Controlled oxidation: Butan-1-ol → Butanal
Oxidation removes hydrogen from the O-H bond and the OH-bearing carbon to form C=O. Separating butanal as it forms limits its further oxidation.
- Aldehyde oxidation: Butanal → Butanoic acid
The hydrated aldehyde is oxidised to a carboxyl group. All four starting carbon atoms remain together in butanoic acid.
- Esterification: Butan-1-ol → Butyl acetate
The alcohol oxygen attacks an activated ethanoic-acid carbonyl. The four-carbon chain remains on oxygen while the two-carbon acetate fragment supplies the carbonyl.
- Acid hydrolysis: Butyl acetate → Butan-1-ol
Hydrolysis breaks the acyl-to-oxygen connection after water addition and proton transfer. The original butyl group stays attached to oxygen and leaves as butan-1-ol.
References
- Organic Chemistry: Nucleophilic Addition of Hydride and Grignard ReagentsJohn McMurry · OpenStax Organic Chemistry · 2023
Supports hydride addition to aldehydes and ketones followed by protonation to form alcohols; used as the mechanism-pattern source for the aldehyde-to-primary-alcohol template.