Reduction

Overview

Reduction of an aldehyde gives a primary alcohol.

Transformation

Aldehydes → Primary alcohols

Equation

R-CHO + 2[H] -> R-CH2OH

Reagents

LiAlH4

Environment

dry ether, then aqueous work-up

Reaction class

reduction

Mechanism

hydride reduction

Evidence level

textbook core

Scope and limitations

Scope

Aldehydes can be reduced to primary alcohols.

Limitations

This route records the reduction outcome; reagent-specific hydride-transfer detail is kept separate from the route summary.

Related reactions

• Cyanohydrin formation: Aldehydes → Hydroxynitriles

  Cyanide addition to an aldehyde forms a hydroxynitrile, giving a carbonyl-route analogue of the nitrile chain-extension motif.

• 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.

• Complete oxidation: Primary alcohols → Carboxylic acids

  Full oxidation of a primary alcohol gives a carboxylic acid.

• Reduction: Carboxylic acids → Primary alcohols

  Reduction of a carboxylic acid gives a primary alcohol.

• Oxidation: Aldehydes → Carboxylic acids

  Oxidation of an aldehyde gives a carboxylic acid.

• Carbonyl addition: Grignard reagents → Primary alcohols

  Grignard addition to methanal gives primary alcohols after work-up.

• Grignard addition co reactant: Methanal → Primary alcohols

  Methanal plus a Grignard reagent gives a primary alcohol after acidic work-up.

• Grignard addition co reactant: Aldehydes → Secondary alcohols

  Aldehydes plus Grignard reagents give secondary alcohols after acidic work-up.

References

1. 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.