Chemistry of the Carbonyl Group
Liam Cox
CHM 1C3
This set of lectures concludes the 1C3 module on Synthesis and Mechanism. We will build on material covered earlier in the course and continue the mechanistic theme. The versatility of the carbonyl group makes it one of the most important functional groups in Organic Chemistry. This set of lectures is devoted exclusively to molecules containing this type of functional group.
Lecture 1 - Introduction
- Names of important carbonyl compounds
- Structure of the carbonyl group using a molecular orbital approach
- Polarisation of the C=O bond; carbonyl groups as electrophiles
Lecture 2-3 - Using spectroscopic tools to identify C=O functional groups
- IR spectroscopy - stretching frequency of different C=O functionalities
- 13C-NMR spectroscopy - position of the C=O resonance
Lecture 4 - Formation of carbonyl compounds using Chromium-based oxidants
- Chemoselectivity issues
- Mechanism
Reactions of aldehydes and ketones
- Formation of olefins using the Wittig reaction
- Reaction mechanism for nucleophilic addition
- Rate-determining formation of a tetrahedral intermediate
- The Bürgi-Dunitz approach trajectory
Lecture 5 - Nucleophilic addition reactions using a range of nucleophiles
- Organolithium and Grignard reagents
- Reduction reactions using aluminium- and boron-based reducing agents.
- Selectivity issues
- Reversibility of the addition reaction
- Hydrates
- Cyanohydrins
Lecture 6 - Carboxylic acid derivatives
- Nucleophilic addition-elimination
- Reaction mechanism
- Relative reactivity of carboxylic acid derivatives
- Predicting leaving group capacity using pKa values
- Understanding why carboxylic acids are poor electrophiles
Lecture 7 - Hydrolysis of methyl esters and amides
- Reaction mechanism
- Acid- and base-catalysis
Lecture 8 - Nitrogen analogues of carbonyl groups
- Imines, hydrazones, oximes
- Mechanism of formation
- Reactivity towards nucleophiles
Lecture 9 - Acetals
- Formation
- Hydrolysis
- Use as a protecting group for carbonyl compounds
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