OrgoChem II

Carbonyls Nucleophilic Addition

Aldehydes and ketones additions and selectivity

Summary

Decide carbonyl type and nucleophile type first then draw. Full reference is on the external link.

What you need to know:

This topic covers carbonyls nucleophilic addition. 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

▶

Grignard Reagent Synthesis Reaction Mechanism

Click to watch on YouTube →

Must know checklist

0 / 5 complete

Carbonyl reactivityaldehydes > ketones (steric and electronic effects); aldehydes have one R group, ketones have two (less electrophilic)
Grignard Reagent Synthesis Reaction Mechanism→
Nucleophilic additionshydride (NaBH4, LiAlH4) → alcohol; Grignard/organolithium (RMgX, RLi) → alcohol; CN- → cyanohydrin; ROH/acid → acetal
Addition of Carbon Nucleophiles to Aldehydes and Ketones→
Imine formationaldehyde/ketone + primary amine → imine (C=N) via hemiaminal intermediate; enamine: aldehyde/ketone + secondary amine → enamine (C-N with C=C)
Imine and Enamine Formation Reactions→
Acetal protectionaldehyde/ketone + 2 ROH + acid catalyst → acetal; stable to base, nucleophiles, reducing agents; deprotect with aqueous acid
Acetal Formation and Deprotection - Carbonyl Protection→
Structure confirmationuse IR (C=O ~1700), NMR (aldehyde H ~9-10 ppm, ketone no aldehyde H), and other spectroscopic data to verify products
Carbonyl Reactivity - Aldehydes vs Ketones→

Common mistakes

Treating carbonyl addition as substitution (no leaving group on aldehyde/ketone)

Forgetting Grignard adds twice to esters (RCO2R → R2C(OH)R)

Not protecting aldehyde when doing selective ketone reduction