Advanced Topic 802 of 1102 Organic Chemistry
Nucleophilic Addition to Carbonyls
Nucleophiles attack the electrophilic carbon of C=O groups.
In-depth explanation of Nucleophilic Addition to Carbonyls
The carbonyl group is polarized so that its carbon is electrophilic, and nucleophiles attack this carbon from the direction above the plane of the C=O bond. The pi electrons move onto the oxygen to give a tetrahedral alkoxide intermediate, which is then protonated to give the alcohol-type product. Aldehydes react faster than ketones because they have less steric hindrance and their carbonyl carbon is more electrophilic. Common nucleophiles include hydride, cyanide, Grignard reagents, amines and alcohols.
Going deeper: Nucleophilic Addition to Carbonyls
Key ideas: The nucleophile attacks the planar carbonyl carbon (delta plus) from either face, converting sp2 to an sp3 alkoxide that is then protonated. Reactivity: formaldehyde > aldehydes > ketones. Strong nucleophiles (Grignard, hydride) add irreversibly; weak ones (HCN, NaHSO3, water, alcohols) add reversibly and are acid or base catalysed. Chiral products are racemic.
Common mistakes and connections: Students draw the nucleophile attacking oxygen. Another error is thinking HCN addition needs strong acid; it needs catalytic base to generate cyanide, since HCN is a weak acid. Links to cyanohydrin formation, acetal protection, the aldol reaction and the contrast with substitution at acyl carbons.
Visualization of Nucleophilic Addition to Carbonyls
The nucleophile attacks the electrophilic carbonyl carbon, pushing the pi electrons onto oxygen to form an alkoxide, then protonation. The interactive lesson shows this as a live animation or chart.
Worked example and use case
Acetone reacts with hydrogen cyanide to give a cyanohydrin, a compound with both OH and CN on the same carbon.
Frequently asked questions about Nucleophilic Addition to Carbonyls
What is Nucleophilic Addition to Carbonyls?
Nucleophiles attack the electrophilic carbon of C=O groups.
Is Nucleophilic Addition to Carbonyls a beginner, intermediate or advanced topic?
Nucleophilic Addition to Carbonyls is a advanced topic in Organic Chemistry. It builds on beginner and intermediate topics, so review those first if needed.
What should I learn before Nucleophilic Addition to Carbonyls?
Study these earlier topics in Organic Chemistry first: Williamson Ether Synthesis, Aldehydes, Ketones.
What comes after Nucleophilic Addition to Carbonyls?
The next topics in Organic Chemistry are Aldol Condensation and Cannizzaro Reaction.
Can I practise Nucleophilic Addition to Carbonyls with quizzes?
Yes. The interactive lesson includes a self-check question on Nucleophilic Addition to Carbonyls, and the Organic Chemistry quiz draws on every topic in this area.
Where Nucleophilic Addition to Carbonyls fits in Organic Chemistry
Nucleophilic Addition to Carbonyls is topic 74 of 148 in Organic Chemistry.