1. ALDEHYDES AND KETONES

2. ALDEHYDES AND KETONES
“carbonyl” functional group:
Aldehydes Ketones

3. Nomenclature:
Aldehydes, common names:
Aldehyde name comes from Alcohol DEHYDrogenation
butyraldehyde isobutyraldehyde
(α-methylpropionaldehyde)

5. Aldehydes, IUPAC nomenclature:
Parent chain = longest continuous carbon chain containing the carbonyl group; alkane, drop –e, add –al. -CH=O is carbon #1.)
CH3
CH3CH2CH2CH=O CH3CHCH=O
butanal methylpropanal
H2C=O CH3CH=O
methanal ethanal

6. Ketones, common names:
Special name: acetone
“alkyl alkyl ketone” or “dialkyl ketone”

7. Ketones: IUPAC nomenclature:
Parent = longest continuous carbon chain containing the carbonyl group. Alkane, drop –e, add –one. Prefix a locant for the position of the carbonyl using the principle of lower number.

8. Physical Properties
The polar carbonyl group makes ketones and aldehydes polar.
Their melting and boiling points increase as the molecular weights increase.
Their boiling points are comparable with alcohols or carboxylic acids.
The lower aldehydes and ketones are appreciably soluble in water and borderline solubility is reached at about five carbons.
They are soluble in the normal organic solvents.
Formaldehyde is a gas at room temperature (BP -21 oC) and is used either as an aqueous solution (formalin - formaldehyde dissolved in methanol)

9. Preparation of Aldehydes and Ketones
Oxidation of alcohols

10. Oxidation of methylbenzenes

11. Reduction of acid chlorides
LiAlH(O-t-Bu)3 tritertier butoxylithium aluminum hydride

12. Preparation of Ketones
Oxidation of Secondary alcohols

13. Friedel-Crafts acylation
Acid chloride
Ketone

14. Reactions of Aldehydes Ketones
Addition of Grignard regents

15. Addition of Alcohols. Acetal formation

16. Addition of cyanide.
This reaction extends chain by one carbon

17. Keto-enol tautomerism of aldehydes and ketones.

18. In keto-enol tautomerism, the aldehyde or the ketone is called the keto form and the enol is called the enol form.  
In most keto-enol tautomerisms, the equilibrium lies by far toward the keto form, indicating that the keto form is usually much more stable than the enol form, which can be attributed to the feet that a carbon-oxygen double bond is significantly stronger than a carbon-carbon double bond.