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Aldehydes, ketones

Aldehydes, ketones. Required background: Structure of alkenes Nucleophilic substitution S N 1, S N 2 Essential for: 1. Carboxylic aids and their derivatives, lipids 2. Enols, enolates 3. Aminoacids, peptides 4. Carbohydrates and nucleic acids.

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Aldehydes, ketones

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  1. Aldehydes, ketones

  2. Required background: Structure of alkenes Nucleophilic substitution SN1, SN2 Essential for: 1. Carboxylic aids and their derivatives, lipids 2. Enols, enolates 3. Aminoacids, peptides 4. Carbohydrates and nucleic acids

  3. Outline 1. Structure and physical properties of carbonyl compounds 2. Nomenclature of aldehydes and ketones 3. Preparation of aldehydes and ketones 4. Nucleophilic addition to the carbonyl group 5. Reduction of aldehydes and ketones 7. Acetals and their use in synthesis 8. Reaction of aldehydes and ketones with ammonia and primary amines 9. Enoles and enolates 10. Aldol condensation

  4. Outline 1. Structure and physical properties of carbonyl compounds 2. Nomenclature of aldehydes and ketones 3. Preparation of aldehydes and ketones 4. Nucleophilic addition to the carbonyl group 5. Reduction of aldehydes and ketones 7. Acetals and their use in synthesis 8. Reaction of aldehydes and ketones with ammonia and primary amines 9. Enoles and enolates 10. Aldol condensation

  5. Outline 1. Structure and physical properties of carbonyl compounds 2. Nomenclature of aldehydes and ketones 3. Preparation of aldehydes and ketones 4. Nucleophilic addition to the carbonyl group 5. Reduction of aldehydes and ketones 7. Acetals and their use in synthesis 8. Reaction of aldehydes and ketones with ammonia and primary amines 9. Enoles and enolates 10. Aldol condensation

  6. Preparation of aldehydes and ketones a.Oxidation of alcohols b. Friedel-Crafts acylation c. Hydration of alkynes d. Ozonolysis of alkynes e. Cleavage of glycols Nucleophilic addition to the carbonyl group

  7. Aldehydes are more reactive, than ketones due to the steric reasons and a larger positive charge on the carbonyl carbon in aldehydes. Addition to C=O bonds is faster, than addition to C=C bonds due to the higher polarity of the C=O bond, but less favorable thermodynamically due to the stronger C=O bond vs. the C=C bond. Example: Cyanohydrin synthesis Reduction of aldehydes and ketones

  8. Outline 1. Structure and physical properties of carbonyl compounds 2. Nomenclature of aldehydes and ketones 3. Preparation of aldehydes and ketones 4. Nucleophilic addition to the carbonyl group 5. Reduction of aldehydes and ketones 7. Acetals and their use in synthesis 8. Reaction of aldehydes and ketones with ammonia and primary amines 9. Enoles and enolates 10. Aldol condensation

  9. Examples:

  10. Acetals and hemiacetals can be formed intramolecularly Due to the stability of acetals toward bases and nucleophiles, they are often used as protecting groups

  11. Outline 1. Structure and physical properties of carbonyl compounds 2. Nomenclature of aldehydes and ketones 3. Preparation of aldehydes and ketones 4. Nucleophilic addition to the carbonyl group 5. Reduction of aldehydes and ketones 7. Acetals and their use in synthesis 8. Reaction of aldehydes and ketones with ammonia and primary amines 9. Enoles and enolates 10. Aldol condensation

  12. Reactions of aldehydes and ketones with ammonia and its derivatives

  13. Examples:

  14. Outline 1. Structure and physical properties of carbonyl compounds 2. Nomenclature of aldehydes and ketones 3. Preparation of aldehydes and ketones 4. Nucleophilic addition to the carbonyl group 5. Reduction of aldehydes and ketones 7. Acetals and their use in synthesis 8. Reaction of aldehydes and ketones with ammonia and primary amines 9. Enoles and enolates 10. Aldol condensation

  15. Theequilibrium is strongly shifted toward the carbonyl form, especially in polar solvents

  16. In esters, enolization is even less favorable due to stabilization of the carbonyl group. Stabilization of the carbonyl form decreases acidity of the compound

  17. Stabilization of the double bond (by conjugation) shifts the equilibrium toward the enol. Enolization, catalyzed by acids

  18. Outline 1. Structure and physical properties of carbonyl compounds 2. Nomenclature of aldehydes and ketones 3. Preparation of aldehydes and ketones 4. Nucleophilic addition to the carbonyl group 5. Reduction of aldehydes and ketones 7. Acetals and their use in synthesis 8. Reaction of aldehydes and ketones with ammonia and primary amines 9. Enoles and enolates 10. Aldol condensation

  19. Aldol reaction (acid catalyzed)

  20. Aldol reaction (base catalyzed)

  21. Examples:

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