OrgoChem II

Carboxylic Acids and Derivatives

Acyl substitution and derivative reactivity ladder

Summary

This is substitution not addition. Use leaving group logic. Full reference is on the external link.

What you need to know:

This topic covers carboxylic acids and derivatives. Focus on mastering the key concepts in the "Must know checklist" below. Follow the study steps systematically, and use practice problems to reinforce your understanding. The external reference provides comprehensive coverage of all concepts.

Video Tutorial

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Nucleophilic Acyl Substitution Reaction Mechanism - Carboxylic Acid Derivatives

Click to watch on YouTube →

Must know checklist

0 / 5 complete

Reactivity ladderacyl chloride > anhydride > ester > carboxylic acid > amide (based on leaving group ability; Cl- > RCO2- > RO- > OH- > NH2-)
Nucleophilic Acyl Substitution Reaction Mechanism→
Nucleophilic acyl substitutiontwo-step addition-elimination; nucleophile attacks carbonyl → tetrahedral intermediate → leaving group expelled; NOT addition like aldehydes/ketones
Carboxylic Acid Derivatives Reactivity Ladder→
Conversionsacid → acid chloride (SOCl2, PCl5); acid chloride → ester (ROH/pyridine); acid chloride → amide (NH3, RNH2); ester → amide (NH3, excess); transesterification (ROH/acid)
Converting Between Carboxylic Acid Derivatives - Acid Chlorides→
Decarboxylationβ-ketoacids and malonic acids decarboxylate on heating; β-dicarbonyls are acidic (pKa ~9-13) due to enolate stabilization
Decarboxylation and Beta-Ketoacids - Acyl Substitution→
Spectroscopyacid (broad O-H ~3000, C=O ~1710); ester (C=O ~1735, no O-H); amide (C=O ~1680, N-H ~3300); acid chloride (C=O ~1800, very reactive)
Spectroscopy of Carboxylic Acid Derivatives - IR→

Common mistakes

Going up the reactivity ladder (amide → acid chloride) without special reagents

Using NH3 with ester instead of excess to get amide

Forgetting decarboxylation needs β-dicarbonyl or β-ketoacid