it gives a brief information about ketones and aldehydes

1. Aldehydes and Ketones

2. Before you can learn about aldehydes and
ketones, you must first know something about
the nomenclature of carboxylic acids since many
of the names of aldehydes and ketones are
derived from the names of the corresponding
carboxylic acids.

3. Carboxylic acids:
R-COOH, R-CO2H,
O
R C
OH
Common names:
HCO2H formic acid L. formica ant
CH3CO2H acetic acid L. acetum vinegar
CH3CH2CO2H propionic acid G. “first salt”
CH3CH2CH2CO2H butyric acid L. butyrum butter
CH3CH2CH2CH2CO2H valeric acid L. valerans

4. Carboxylic acids, common names:
…
CH3(CH2)4CO2H caproic acid L. caper goat
CH3(CH2)5CO2H ---
CH3(CH2)6CO2H caprylic acid
CH3(CH2)7CO2H ---
CH3(CH2)8CO2H capric acid
CH3(CH2)9CO2H ---
CH3(CH2)10CO2H lauric acid oil of lauryl

5. 5 4 3 2 1
C—C—C—C—C=O
δ γ β α used in common names
Br
CH3CH2CH2CHCOOH
CH3
CH3CHCH2COOH
 bromovaleric acid  -methylbutyric acid
isovaleric acid

6. COOH
Special names!
COOH COOH COOH
CH3
CH3
CH3
benzoic acid
o-toluic acid m-toluic acid p-toluic acid

7. ALDEHYDES AND KETONES
“carbonyl” functional group:
O
C
Aldehydes Ketones
H
C
H
O
R
C
H
O
R
C
R'
O
R can be Ar

8. Nomenclature:
Aldehydes, common names:
Derived from the common names of carboxylic acids;
drop –ic acid suffix and add –aldehyde.
CH3
CH3CH2CH2CH=O CH3CHCH=O
butyraldehyde isobutyraldehyde
(α-methylpropionaldehyde)

9. CHO
benzaldehyde
CHO
CH3
o-tolualdehyde
H
C
H
O
formaldehyde
CH2CH=O
phenylacetaldehyde

10. Aldehydes, IUPAC nomenclature:
Parent chain = longest continuous carbon chain containing
the carbonyl group; alkane, drop –e, add –al. (note: no
locant, -CH=O is carbon #1.)
CH3
CH3CH2CH2CH=O CH3CHCH=O
butanal 2-methylpropanal
H2C=O CH3CH=O
methanal ethanal

11. Ketones, common names:
O
C
Special name: acetone
H3C
CH3
“alkyl alkyl ketone” or “dialkyl ketone”
O
CH3CH2CCH3
O
CH3CH2CCH2CH3
ethyl methyl ketone diethyl ketone
O
CH3CCH2CH2CH3
methyl n-propyl ketone

12. (o)phenones:
O
R C
Derived from common name of carboxylic acid, drop –ic
acid, add –(o)phenone.
O
C
H3C
O
C
benzophenone acetophenone

13. 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.
O
CH3CH2CCH3
O
CH3CH2CCH2CH3
2-butanone 3-pentanone
O
CH3CCH2CH2CH3
2-pentanone

14. Physical properties:
C O sp2 120o
C O C O
polar, no hydrogen bonding
mp/bp are relatively moderate for covalent substances
water insoluble
(except: four-carbons or less)


15. Spectroscopy:
IR: C=O stretch, strong ~1700 cm-1
RCHO 1725 ArCHO 1700
R2CO 1710 ArCOR 1690
C—H stretch for aldehydes 2720
nmr: -CHO 9-10 ppm

16. acetophenone
C=O
stretch

17. valeraldehyde
CHO
C—H
stretch
2720 cm-1
C=O stretch

18. valeraldehyde
CH3CH2CH2CH2CH=O
a b c d e
-CHO

19. Oxidation/Reduction:
oxidation numbers:
oxidation
-4 -2 0 +2 +4
CH4 CH3OH H2C=O HCO2H CO2
alkane alcohol aldehyde carboxylic acid
reduction

20. Aldehydes, syntheses:
1. Oxidation of 1o alcohols
2. Oxidation of methylaromatics
3. Reduction of acid chlorides
Ketones, syntheses:
1. Oxidation of 2o alcohols
2. Friedel-Crafts acylation
3. Coupling of R2CuLi with acid chloride

21. Aldehydes synthesis 1) oxidation of primary alcohols:
RCH2-OH + K2Cr2O7, special conditions  RCH=O
RCH2-OH + C5H5NHCrO3Cl  RCH=O
(pyridinium chlorochromate)
[With other oxidizing agents, primary alcohols  RCOOH]

22. CH3CH2CH2CH2CH2OH
+ K2Cr2O7 CH3CH2CH2CH2CO2H
1-pentanol
pentanoic acid
K2Cr2O7, special conditions!
CH3CH2CH2CH2CH=O
pentanal
valeraldehyde
CH2OH
C5H5NHCrO3Cl
pyridinium chlorochromate
CH=O
benzyl alcohol benzaldehyde
CH3CH2CH2CH2CH2OH
1-pentanol

23. Aldehyde synthesis: 2) oxidation of methylaromatics:
+ CrO3, (CH3CO)2O
O
C O C
geminal diacetate
H2O, H+
CH3
Br
Br
CH O
H3C
O
H3C
Br
CHO
p-bromobenzaldehyde
Aromatic aldehydes only!

24. CH3
2-methylnaphthalene 2-naphthaldehyde
CH3O CH3
CrO3
(CH3CO)2O
CrO3
H2O
(CH3CO)2O
H2O
CHO
CH3O CH=O
p-methylanisole p-anisaldehyde

25. Aldehyde synthesis: 3) reduction of acid chloride
lithium aluminum hydride tri-tert-butoxide
LiAlH(O-t-Bu)3
O
Cl
O
isovaleryl chloride
O
H
O
isovaleraldehyde
R
C
Cl
LiAlH(O-t-Bu)3
R
C
H

26. C
O
Cl
LiAlH(O-t-Bu)3
C
O
H
benzoyl chloride benzaldehyde
LiAlH(O-t-Bu)3
CH3CHCH2C
O
Cl
CH3
CH3CHCH2C
O
H
CH3
isovaleryl chloride isovaleraldehyde

27. Ketone synthesis: 1) oxidation of secondary alcohols
H OH O
NaOCl
cyclohexanol cyclohexanone
K2Cr2O7
H3C
O
C
CH3
OH
CH3CHCH3
isopropyl alcohol acetone

28. Ketone synthesis: 2) Friedel-Crafts acylation
AlCl3
O
RCOCl, AlCl3 + ArH R C Ar
+ HCl
CH3CH2CH2C
O
Cl
+
AlCl3
Aromatic ketones (phenones) only!
O
CH3CH2CH2C
butyrophenone

29. +
AlCl3
O
m-nitrobenzophenone
O2N
O
C Cl
C
O2N
+
AlCl3
O
C Cl
NO2
NR
Friedel Crafts acylation does not work on deactivated rings.

30. Mechanism for Friedel-Crafts acylation EAS
R
C
Cl
O
+ AlCl3 RC=O + AlCl4
+ RC=O
RDS
O
CR
H
O
CR
H
+ AlCl4
O
C R
+ HCl + AlCl3

31. Ketone synthesis: 3) coupling of RCOCl and R2CuLi
RCOCl + R'2CuLi
R
O
C
R'
Cl
O
+ (CH3CH2)2CuLi
O
lithium diethylcuprate
Isobutyryl chloride 2-Methyl-3-pentanone

32. CuLi
2
O
+ CHCH2CH2CH3
Cl
O
CCH2CH2CH3
butyrophenone
CH3CH2CH2C
O
Cl
CH3
+ CH3CH
CuLi CH3CH2CH2CCHCH3
2
O
CH3
2-methyl-3-hexanone

33. Aldehydes, syntheses:
1. Oxidation of 1o alcohols
2. Oxidation of methylaromatics aromatic only
3. Reduction of acid chlorides
Ketones, syntheses:
1. Oxidation of 2o alcohols
2. Friedel-Crafts acylation aromatic only
3. Coupling of R2CuLi with acid chloride

34. K2Cr2O7, special cond.
or C5H5NHCrO3Cl
aldehyde
1o alcohol
Ar-CH3
acid chloride
CrO3 H2O
(AcO)2O
LiAlH(O-t-Bu)3

35. ketone
2o alcohol
acid chloride + ArH
NaOCl, etc.
AlCl3
acid chloride + R2CuLi

36. 1. outline three different syntheses for benzaldehyde
2. outline three different syntheses for benzophenone
3. outline a different synthesis for each of the
following compounds:
cyclohexanone, 4-bromobenzaldehyde, 2-pentanone,
valeraldehyde, acetophenone, isobutyraldehyde,

37. CH2OH
K2Cr2O7
special conditions
CH3
CrO3
(CH3CO)2O
CH(OOCCH3)2
H2O
O
C
Cl
LiAlH(O-t-Bu)3
CH=O
benzaldehyde
Synthesize benzaldehyde three different ways.

38. OH
CH
NaOCl
O
C
Cl
+
AlCl3
O
C
Cl
+ CuLi
2
O
C
Synthesize benzophenone three different ways.

39. cyclohexanone, 4-bromobenzaldehyde, 2-pentanone,
valeraldehyde, acetophenone, isobutyraldehyde, using a
different method for each one.
O
Br CHO
oxidation of 2o alcohol oxidation of Ar-CH3
O
CH3CH2CH2CCH3
CH3CH2CH2CH2CHO
O
CH3C
CH3
CH3CHCHO
R2CuLi + R'COCl
Friedel-Crafts acylation
oxidation of 1o alcohol
reduction of acid chloride

40. O
O
CH3CH2CH2CCH3
O
CH3C
H
OH
K2Cr2O7
O
(CH3CH2CH2)CuLi + CH3 C
O
CH3 C
Cl
+
AlCl3
Cl

41. Br CHO
CH3CH2CH2CH2CHO
CH3
CH3CHCHO
Br CH3
CrO3
(CH3CO)2O
CH3CH2CH2CH2CH2-OH
H2O
K2Cr2O7
special conditions
CH3 O
CH3CHC
Cl
LiAlH(O-t-bu)3
The methods could be reversed for the last two syntheses.