1. Aldehydes and Ketones

2. Carbonyl compounds
The compounds occur widely in nature as intermediates in metabolism and biosynthesis
They are also common as chemicals, as solvents, monomers, adhesives, agrichemicals and pharmaceuticals
planar about the double bond and have bond angles of approximately 120°.
Strongly polarized because of the high electronegativity of oxygen relative to carbon.
Thus, the carbonyl carbon atom carries a partial positive charge, is an electrophilic (Lewis acidic) site, and reacts with nucleophiles.

3. Examples of carbonyl compounds
Amoxicillin

5. Carbonyl compounds reactions
1- Nucleophilic addition reactions
2- Nucleophilic acyl substitution reactions

6. Carbonyl compounds reactions
3- Alpha-Substitution Reactions
4- Carbonyl Condensation Reactions
Enolate formation mechanism
Example of reaction with primary alkyl halides in the SN2 reaction – making c-c bond

7. Naming Aldehydes and Ketones
Aldehydes are named by replacing the terminal -e of the corresponding alkane name with –al
The parent chain must contain the CHO group
The CHO carbon is numbered as C1
2-(1-chloroethyl)-4-methylpentanal
If the CHO group is attached to a ring, use the suffix -carbaldehyde

8. Common names for aldehydes

9. Naming Ketones Replace the terminal -e of the alkane name with –one
Parent chain is the longest one that contains the ketone group
Numbering begins at the end nearer the carbonyl carbon

10. Ketones with Common Names

11. Ketones and Aldehydes as Substituents
The R–C=O as a substituent is an acyl group is used with the suffix -yl from the root of the carboxylic acid
CH3CO: acetyl; CHO: formyl; C6H5CO: benzoyl
The prefix oxo- is used if other functional groups are present and the doubly bonded oxygen is labeled as a substituent on a parent chain

12. Preparation of Aldehydes and Ketones
Preparing Aldehydes
Oxidize primary alcohols using pyridinium chlorochromate (PCC)
Reduce an ester with diisobutylaluminum hydride (DIBAH)

13. Preparing Ketones Oxidize a 2° alcohol
Many reagents possible: choose for the specific situation (scale, cost, and acid/base sensitivity)

14. Aryl Ketones by Acylation
Friedel–Crafts acylation of an aromatic ring with an acid chloride in the presence of AlCl3 catalyst

15. Methyl Ketones by Hydrating Alkynes
Hydration of terminal alkynes in the presence of Hg2+

16. Ketone and Aldehyde from Ozonolysis
Ozonolysis of alkenes yields ketones if one of the unsaturated carbon atoms is disubstituted

17. Oxidation of Aldehydes
CrO3 in aqueous acid oxidizes aldehydes to carboxylic acids efficiently
Silver oxide, Ag2O, in aqueous ammonia (Tollens’ reagent) oxidizes aldehydes (no acid)
KMnO4

18. Nucleophilic Addition Reactions of Aldehydes and Ketones
Nu- approaches 45° to the plane of C=O and adds to C
A tetrahedral alkoxide ion intermediate is produced

19. Electrophilicity of Aldehydes and Ketones
Aldehydes are generally more reactive than ketones in nucleophilic addition reactions
Aldehydes have one large substituent bonded to the C=O: ketones have two
Aldehyde C=O is more polarized than ketone C=O
Ketone has more alkyl groups, stabilizing the C=O carbon inductively (Similar to carbocation)

20. Reactivity of Aromatic Aldehydes
Less reactive in nucleophilic addition reactions than aliphatic aldehydes
Electron-donating resonance effect of aromatic ring makes C=O less reactive electrophilic than the carbonyl group of an aliphatic aldehyde

21. Nucleophilic Addition of HCN: Cyanohydrin Formation
Aldehydes and unhindered ketones react with HCN to yield cyanohydrins, RCH(OH)CN

22. Uses of Cyanohydrins
The nitrile group (CN) can be reduced with LiAlH4 to yield a primary amine (RCH2NH2)
Can be hydrolyzed by hot acid to yield a carboxylic acid

23. Nucleophilic Addition of Amines: Imine and Enamine Formation
RNH2 adds to C=O to form imines, R2C=NR (after loss of HOH)
R2NH yields enamines, R2NCR=CR2 (after loss of HOH)
(ene + amine = unsaturated amine)

24. Based on McMurry, Organic Chemistry, Chapter 19, 6th edition, (c) 2003
Imine Derivatives
Addition of amines with an atom containing a lone pair of electrons on the adjacent atom occurs very readily, giving useful, stable imines
For example, hydroxylamine forms oximes and 2,4-dinitrophenylhydrazine readily forms 2,4-dinitrophenylhydrazones
Based on McMurry, Organic Chemistry, Chapter 19, 6th edition, (c) 2003

25. Nucleophilic Addition of Hydrazine: The Wolff–Kishner Reaction
Treatment of an aldehyde or ketone with hydrazine, H2NNH2 and KOH converts the compound to an alkane

26. Illegal drugs synthesis
Can you suggest a synthesis for methamphetamine from Pseudoephidrine?
Can you suggest a synthesis for Pethidine from 1-methylpiperidin-4-one?

27. Uses of the Wittig Reaction
Can be used to convert C=O to C=C
The reaction yields a pure alkene of known structure
For comparison, addition of CH3MgBr to cyclohexanone and dehydration with, yields different type of alkene
Triphenylphosphine and triphenylphosphine oxide

28. Alcohol – Reactions – Dehydration
where isomeric alkenes are possible, the alkene having the greater number of substituents on the double bond (the more stable alkene) usually predominates (Zaitsev rule)

29. Nucleophilic Addition of Alcohols: Ketal/Acetal Formation
Two equivalents of ROH in the presence of an acid catalyst add to C=O to yield acetals, R2C(OR)2
These can be called ketals if derived from a ketone, or acetal if derived from aldehyde

30. Formation of Ketals/Acetals
Alcohols are weak nucleophiles but acid promotes addition forming the conjugate acid of C=O
Addition yields a hydroxy ether, called a hemiketal (reversible); further reaction can occur
Protonation of the OH and loss of water leads to an oxonium ion, R2C=OR+ to which a second alcohol adds to form the ketal.

31. Uses of Acetals
Acetals can serve as protecting groups for aldehydes and ketones
It is convenient to use a diol, to form a cyclic acetal (the reaction goes even more readily)