Carbonyl addition

Overview

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

Transformation

Grignard reagents → Primary alcohols

Equation

R-MgX + HCHO -> R-CH2OMgX; then H3O+ -> R-CH2OH

Reagents

methanal then dilute acid

Environment

dry ether, then acidic work-up

Reaction class

nucleophilic addition

Mechanism

Grignard carbonyl addition

Evidence level

textbook core

Scope and limitations

Scope

Grignard reagents add to methanal and, after acidic work-up, give primary alcohols.

Limitations

This route records the carbonyl-addition and acidic work-up outcome; Grignard reagents must be kept dry before work-up.

Related reactions

• 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: Aldehydes → Primary alcohols

  Reduction of an aldehyde gives a primary alcohol.

• Reduction: Carboxylic acids → Primary alcohols

  Reduction of a carboxylic acid gives a primary alcohol.

• Grignard formation: Chloroalkanes → Grignard reagents

  Chloroalkanes can react with magnesium in dry ether to form Grignard reagents.

• Grignard formation: Bromoalkanes → Grignard reagents

  Bromoalkanes can react with magnesium in dry ether to form Grignard reagents.

• Grignard formation: Iodoalkanes → Grignard reagents

  Iodoalkanes can react with magnesium in dry ether to form Grignard reagents.

• Carbonyl addition: Grignard reagents → Secondary alcohols

  Grignard addition to aldehydes gives secondary alcohols after work-up.

• Carbonyl addition: Grignard reagents → Tertiary alcohols

  Grignard addition to ketones gives tertiary alcohols after work-up.

• Carboxylation: Grignard reagents → Carboxylic acids

  Grignard carboxylation gives carboxylic acids after acidic work-up.

• Grignard addition co reactant: Methanal → Primary alcohols

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

References

1. Organic Chemistry: Nucleophilic Addition of Hydride and Grignard ReagentsJohn McMurry · OpenStax Organic Chemistry · 2023

   Supports Grignard carbon nucleophiles adding to aldehydes and ketones to give alkoxide intermediates, followed by protonation during acidic work-up.