Carboxylation

Overview

Grignard carboxylation gives carboxylic acids after acidic work-up.

Transformation

Grignard reagents → Carboxylic acids

Equation

R-MgX + CO2 -> R-CO2MgX; then H3O+ -> R-CO2H

Reagents

dry CO2 then dilute acid

Environment

dry ether, then acidic work-up

Reaction class

carboxylation

Mechanism

Grignard carboxylation

Evidence level

textbook core

Scope and limitations

Scope

Grignard reagents react with carbon dioxide and then acid work-up to form carboxylic acids.

Limitations

This route records the carboxylation and acidic work-up outcome; Grignard reagents must be kept dry before reaction with carbon dioxide.

Related reactions

• Oxidation: Alcohols → Carboxylic acids

  Full oxidation of a primary alcohol gives a carboxylic acid.

• 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.

• 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.

• Activation for amide formation: Carboxylic acids → Amide chemistry

  Carboxylic acids or activated acid derivatives connect to amide-bond formation.

• Esterification: Carboxylic acids → Esters

  Carboxylic acids react with alcohols to form esters.

• Hydrolysis: Esters → Carboxylic acids

  Hydrolysis converts esters back into carboxylic acid products.

• Chlorination: Carboxylic acids → Acyl chlorides

  PCl5 converts carboxylic acids into acyl chlorides.

• Chlorination with thionyl chloride: Carboxylic acids → Acyl chlorides

  Thionyl chloride converts carboxylic acids into acyl chlorides with sulfur dioxide and hydrogen chloride as by-products.

• Hydrolysis: Acyl chlorides → Carboxylic acids

  Water hydrolyses acyl chlorides to carboxylic acids, releasing hydrogen chloride.

• 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 → Primary alcohols

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

• Carbonyl addition: Grignard reagents → Secondary alcohols

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

References

1. Organic Chemistry: Preparing Carboxylic AcidsJohn McMurry · OpenStax Organic Chemistry · 2023

   Supports dry carbon dioxide reacting with Grignard reagents to form carboxylates that give carboxylic acids after acidic work-up.