1. Chapter 17 Aldehydes and Ketones: Nucleophilic Addition to the Carbonyl Group Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

2. 17.1 Nomenclature

3. IUPAC Nomenclature of Aldehydes H OO H O HCCHCH O Base the name on the chain that contains the carbonyl group and replace the -e ending of the hydrocarbon with -al.

4. 4,4-dimethylpentanal5-hexenal or hex-5-enal IUPAC Nomenclature of Aldehydes H OO H O HCCHCH O 2-phenylpropanedial (keep the -e ending before -dial)

5. when named as a substituent formyl group carbaldehyde or carboxaldehyde when named as a suffix C H O IUPAC Nomenclature of Aldehydes

6. CH 3 CH 2 CCH 2 CH 2 CH 3 O CH 3 CHCH 2 CCH 3 O CH 3 H3CH3C O Base the name on the chain that contains the carbonyl group and replace -e with -one. Number the chain in the direction that gives the lowest number to the carbonyl carbon. Substitutive IUPAC Nomenclature of Ketones

7. CH 3 CH 2 CCH 2 CH 2 CH 3 O CH 3 CHCH 2 CCH 3 O CH 3 H3CH3C O 3-hexanone or hexan-3-one 4-methyl-2-pentanone or 4-methylpentan-2-one 4-methylcyclohexanone

8. Functional Class IUPAC Nomenclature of Ketones CH 3 CH 2 CCH 2 CH 2 CH 3 OO CH 2 CCH 2 CH 3 CH CH 2 O H2CH2C CHC List the groups attached to the carbonyl separately in alphabetical order, and add the word ketone.

9. CH 3 CH 2 CCH 2 CH 2 CH 3 O ethyl propyl ketonebenzyl ethyl ketone divinyl ketone O CH 2 CCH 2 CH 3 CH CH 2 O H2CH2C CHC Functional Class IUPAC Nomenclature of Ketones

10. 17.2 Structure and Bonding: The Carbonyl Group

11. planar bond angles: close to 120° C=O bond distance: 122 pm Structure of Formaldehyde

12. 1-butene propanal The Carbonyl Group O dipole moment = 0.3D dipole moment = 2.5D very polar double bond

13. 2475 kJ/mol 2442 kJ/mol Alkyl groups stabilize carbonyl groups the same way they stabilize carbon-carbon double bonds, carbocations, and free radicals. heat of combustion Carbonyl Group of a Ketone is More Stable than that of an Aldehyde O O H

14. Heats of combustion of C 4 H 8 isomeric alkenes CH 3 CH 2 CH=CH 2 2717 kJ/mol cis-CH 3 CH=CHCH 3 2710 kJ/mol trans-CH 3 CH=CHCH 3 2707 kJ/mol (CH 3 ) 2 C=CH 2 2700 kJ/mol 2475 kJ/mol 2442 kJ/mol O O H Spread is Greater for Aldehydes and Ketones than for Alkenes

15. Nucleophiles attack carbon; electrophiles attack oxygen. Resonance Description of Carbonyl Group C O C O + –

16. Carbon and oxygen are sp 2 hybridized. Bonding in Formaldehyde

17. The half-filled 2p orbitals on carbon and oxygen overlap to form a  bond. Bonding in Formaldehyde

18. 17.3 Physical Properties

19. boiling point –6°C 49°C 97°C Aldehydes and Ketones have Higher Boiling Points than Alkenes, but Lower Boiling Points than Alcohols More polar than alkenes, but cannot form intermolecular hydrogen bonds to other carbonyl groups. O OH

20. 17.4 Sources of Aldehydes and Ketones

21. 2-heptanone (component of alarm pheromone of bees) O Many Aldehydes and Ketones Occur Naturally

22. trans-2-hexenal (alarm pheromone of myrmicine ant) Many Aldehydes and Ketones Occur Naturally O H

23. citral (from lemon grass oil) Many Aldehydes and Ketones Occur Naturally O H

24. from alkenes ozonolysis from alkynes hydration (via enol) from arenes Friedel-Crafts acylation from alcohols oxidation Table 17.1 Synthesis of Aldehydes and Ketones A number of reactions already studied provide efficient synthetic routes to aldehydes and ketones.

25. C O R OH aldehydes from carboxylic acids RCH 2 OH 1. LiAlH 4 2. H 2 O PDC, CH 2 Cl 2 H C O R What About..?

26. Benzaldehyde from benzoic acid COH O CHCH O 1. LiAlH 4 2. H 2 O PDC CH 2 Cl 2 CH 2 OH (81%) (83%) Example

27. C O R H Ketones from aldehydes R' R C O PDC, CH 2 Cl 2 1. R'MgX 2. H 3 O + RCHR' OH What About..?

28. C O CH 3 CH 2 H 3-heptanone from propanal H 2 CrO 4 1. CH 3 (CH 2 ) 3 MgX 2. H 3 O + CH 3 CH 2 CH(CH 2 ) 3 CH 3 OH O CH 3 CH 2 C(CH 2 ) 3 CH 3 (57%) Example