R Organic Chemistry,5th Edition L.G.Wade,Jr. Chapter 18 Ketones and Aldehydes Jo Blackburn Richland College,Dallas,TX Dallas County Community College District ©2003，Prentice Hall
Chapter 18 Ketones and Aldehydes Jo Blackburn Richland College, Dallas, TX Dallas County Community College District © 2003, Prentice Hall Organic Chemistry, 5th Edition L. G. Wade, Jr
Carbonyl Compounds TABLE 18-1 Some Common Classes of Carbonyl Compounds Class General Formula Class General Formula ketones R aldehydes R-C-H carboxylic acids R -OH acid chlorides R esters O-R amides R => Chapter 18 2
Chapter 18 2 Carbonyl Compounds =>
Carbonyl Structure ● Carbon is sp2 hybridized. C=O bond is shorter,stronger,and more polar than C=C bond in alkenes. length energy ketone C=0 bond 1.23A 178 kcal/mol (745 kJ/mol) alkene C=C bond 1.34A 146 kcal/mol (611 kJ/mol) => Chapter 18 3
Chapter 18 3 Carbonyl Structure • Carbon is sp2 hybridized. • C=O bond is shorter, stronger, and more polar than C=C bond in alkenes. =>
IUPAC Names for Ketones Replace -e with -one.Indicate the position of the carbonyl with a number. Number the chain so that carbonyl carbon has the lowest number. For cyclic ketones the carbonyl carbon is assigned the number 1. => Chapter 18
Chapter 18 4 IUPAC Names for Ketones • Replace -e with -one. Indicate the position of the carbonyl with a number. • Number the chain so that carbonyl carbon has the lowest number. • For cyclic ketones the carbonyl carbon is assigned the number 1. =>
Examples CH-CH CH3 3-methyl-2-butanone Br 3-bromocyclohexanone CH C-CH-CBOL CH3 4-hydroxy-3-methyl-2-butanone => Chapter 18 5
Chapter 18 5 Examples CH3 C O CH CH3 CH3 O Br CH3 C O CH CH3 CH2OH 3-methyl-2-butanone 3-bromocyclohexanone 4-hydroxy-3-methyl-2-butanone =>
Naming Aldehydes IUPAC:Replace -e with -al. The aldehyde carbon is number 1. If -CHO is attached to a ring,use the suffix-carbaldehyde. => Chapter 18 6
Chapter 18 6 Naming Aldehydes • IUPAC: Replace -e with -al. • The aldehyde carbon is number 1. • If -CHO is attached to a ring, use the suffix -carbaldehyde. =>
Examples CH3 3-methylpentanal CHO 2-cyclopentenecarbaldehyde => Chapter 18 7
Chapter 18 7 Examples CH3 CH2 CH CH3 CH2 C H O CHO 3-methylpentanal 2-cyclopentenecarbaldehyde =>
Name as Substituent On a molecule with a higher priority functional group,C=O is oxo-and -CHO is formyl. Aldehyde priority is higher than ketone. COOH CHO 3-methyl-4-oxopentanal 3-formylbenzoic acid => Chapter 18 8
Chapter 18 8 Name as Substituent • On a molecule with a higher priority functional group, C=O is oxo- and -CHO is formyl. • Aldehyde priority is higher than ketone. CH3 C CH CH3 CH2 C H O O COOH CHO 3-methyl-4-oxopentanal 3-formylbenzoic acid =>
Common Names for Ketones Named as alkyl attachments to -C=O. Use Greek letters instead of numbers. em t cu-cu CHCH-C-CH-CHs CH3 Br CH3 methyl isopropyl ketone a-bromoethyl isopropyl ketone => Chapter 18 9
Chapter 18 9 Common Names for Ketones • Named as alkyl attachments to -C=O. • Use Greek letters instead of numbers. CH3 C O CH CH3 CH3 CH3CH C O CH CH3 CH3 Br methyl isopropyl ketone a-bromoethyl isopropyl ketone =>
Historical Common Names =U -CH3 acetone acetophenone benzophenone => Chapter 18 10
Chapter 18 10 Historical Common Names CH3 C O CH3 C CH3 O C O acetone acetophenone benzophenone =>