Chapter 18 Ketones and Aldehydes
1) Which of the following correctly describes the bond angle and hybridizations present in
formaldehyde?
A) C, sp2; O, sp3; HCO, ~120°
B) C, sp2; O, sp2; HCO, ~120°
C) C, sp2; O, sp2; HCO, ~109.5°
D) C, sp3; O, sp2; HCO, ~109.5°
E) C, sp3; O, sp3; HCO, ~109.5°
Answer: B
Diff: 1
Section: 18.2
2) The double bond between carbon and oxygen is similar to an alkene C=C, except that C=O is:
A) shorter and weaker.
B) shorter and stronger.
C) longer and weaker.
D) longer and stronger.
E) longer.
Answer: B
Diff: 2
Section: 18.2
3) The positively polarized carbon atom of a carbonyl group acts as:
A) an electrophile and a Lewis base.
B) a nucleophile and a Lewis base.
C) an electrophile and a Lewis acid.
D) a nucleophile and a Lewis acid.
E) both a Lewis acid and a Lewis base.
Answer: C
Diff: 2
Section: 18.2
1
4) Would you expect the carbonyl carbon of benzaldehyde to be more or less electrophilic than
that of acetaldehyde? Explain using resonance structures.
Answer: The carbonyl carbon of benzaldehyde would be less electrophilic. Delocalization
reduces its partial positive charge as seen in the resonance forms below.
Diff: 2
Section: 18.2
5) Another name for β-methoxybutyraldehyde is:
A) 2-methoxypropanal.
B) 3-methoxypropanal.
C) 2-methoxybutanal.
D) 3-methoxybutanal.
E) 2-methoxypentanal.
Answer: D
Diff: 1
Section: 18.3
6) Provide the structure of cyclohexanecarbaldehyde.
Answer:
Diff: 1
Section: 18.3
7) Provide the structure of 4-oxohexanoic acid.
Answer:
Diff: 1
Section: 18.3
2
8) Provide the IUPAC name for the following compound.
Answer: 6-hydroxy-4-nonanone or 6-hydroxynonan-4-one
Diff: 2
Section: 18.3
9) Provide the IUPAC name for (CH3)3CCH2CHClCH2CHO.
Answer: 3-chloro-5,5-dimethylhexanal
Diff: 2
Section: 18.3
10) Give an IUPAC name to the following compound. Be sure to include configurational
information in the name.
Answer: (Z)-4-oxo-2-pentenal or (Z)-4-oxopent-2-enal
Diff: 2
Section: 18.3
11) Draw the ethylene acetal of benzaldehyde.
Answer:
Diff: 2
Section: 18.3
12) Provide the proper IUPAC name for PhCH2CH(CH3)CH2CH2CHO.
Answer: 4-methyl-5-phenylpentanal
Diff: 1
Section: 18.3
13) Provide the proper IUPAC name for CH3CHOHCH2COCH2C(CH3)2CH2CH3.
Answer: 2-hydroxy-6,6-dimethyl-4-octanone
Diff: 1
Section: 18.3
3
14) Provide the proper IUPAC name for CH3OCH2CH2CH(CH3)CHO.
Answer: 4-methoxy-2-methylbutanal
Diff: 1
Section: 18.3
15) Provide the structure of benzophenone.
Answer: PhCOPh
Diff: 1
Section: 18.3
16) Provide the proper IUPAC name for (CH3)2CHCH2CH2COCH
Answer: 6-methylhept-1-en-3-one
Diff: 2
Section: 18.3
2.
17) Provide the proper IUPAC name for CH3CHBrCH2COCH2CHO.
Answer: 5-bromo-3-oxohexanal
Diff: 2
Section: 18.3
18) Which of the following represents the correct ranking in terms of increasing boiling point?
A) n-butane < 1-butanol < diethyl ether < 2-butanone
B) n-butane < 2-butanone < diethyl ether < 1-butanol
C) 2-butanone < n-butane < diethyl ether < 1-butanol
D) n-butane < diethyl ether < 1-butanol < 2-butanone
E) n-butane < diethyl ether < 2-butanone < 1-butanol
Answer: E
Diff: 2
Section: 18.4
19) Which of the following compounds is most soluble in water?
A) acetone
B) cyclohexanone
C) 2-butanone
D) 3-butanone
E) benzophenone
Answer: A
Diff: 2
Section: 18.4
20) Which is more soluble in water, 2-butanone or n-hexane? Explain.
Answer: 2-Butanone is more soluble in water. The polarization of the carbonyl group gives the
molecule a permanent dipole moment. More importantly, the hydrogens of water can hydrogen
bond with the carbonyl oxygen.
Diff: 2
Section: 18.4
4
21) In carbon NMR, the carbon atom of the carbonyl group in aldehydes and ketones has a
chemical shift of about:
A) 20 ppm.
B) 40 ppm.
C) 60 ppm.
D) 120 ppm.
E) 200 ppm.
Answer: E
Diff: 1
Section: 18.5
22) Which compound will show an intense peak in the mass spectrum at m/z 58?
A) CH3COCH2CH2CH3
B) (CH3)2CHCOCH3
C) CH3CH2COCH2CH3
D) (CH3)3CCHO
E) (CH3)3CCOCH3
Answer: A
Diff: 2
Section: 18.5
23) In the mass spectrum of 3,3-dimethyl-2-butanone, the base peak will occur at m/z:
A) 43
B) 58
C) 84
D) 85
E) 100
Answer: A
Diff: 2
Section: 18.5
24) When a carbonyl is part of a conjugated π-network, the C=O stretch:
A) has a higher frequency than in a nonconjugated system.
B) has a lower frequency than in a nonconjugated system.
C) always occurs at 1710 cm-1.
D) occurs around 2700 cm-1.
E) cannot be distinguished from the C=O stretch in a nonconjugated system.
Answer: B
Diff: 2
Section: 18.5
5
25) In the proton NMR spectra of aldehydes and ketones, the protons bonded to carbons adjacent
to the carbonyl group typically fall into which of the chemical shift ranges below?
A) 1.0-2.0 ppm
B) 2.0-3.0 ppm
C) 4.0-4.5 ppm
D) 7.0-8.0 ppm
E) 9.0-10.0 ppm
Answer: B
Diff: 2
Section: 18.5
26) The proton NMR spectrum of an unknown compound contains a triplet at 9.8 ppm. Which of
the following could be this unknown?
A) (CH3)3CCHO
B) CH3CH2CH2CO2H
C) CH3CH2CH2CHO
D) CH3CO CH2Ph
E) PhCHO
Answer: C
Diff: 2
Section: 18.5
27) Which of the following compounds would show only one triplet in its off resonance
decoupled 13C NMR spectrum?
A) acetone
B) butanal
C) pentanal
D) 2-pentanone
E) 3-pentanone
Answer: E
Diff: 2
Section: 18.5
28) Which of the following transitions is usually observed in the UV spectra of ketones?
A) n to π*
B) n to π
C) σ to n
D) σ to σ*
E) n to σ*
Answer: A
Diff: 2
Section: 18.5
6
29) The strongest absorptions in the UV spectra of aldehydes and ketones are ones which result
from __________ electronic transitions.
A) σ to σ*
B) σ to π*
C) n to π*
D) π to π*
E) π to σ*
Answer: D
Diff: 3
Section: 18.5
30) How might one distinguish an aldehyde from a ketone using IR data alone?
Answer: The aldehyde has two C-H stretches at 2700 and 2800 cm-1.
Diff: 2
Section: 18.5
31) What name is given to the linear polymer which contains many formaldehyde units?
A) trioxane
B) formalin
C) paraformaldehyde
D) polyacetaldehyde
E) polyalal
Answer: C
Diff: 2
Section: 18.6
32) Trioxane is a cyclic trimer of formaldehyde that can be converted to formaldehyde upon
heating. Show this reaction.
Answer:
Diff: 2
Section: 18.6
33) What reagent can be used to convert 2-methylbutan-1-ol into 2-methylbutanal?
A) LiAlH4
B) Na2Cr2O7
C) O3
D) KMnO4
E) PCC
Answer: E
Diff: 1
Section: 18.7
7
34) What reagents can be used to convert 1-hexyne into 2-hexanone?
A) 1. Sia2BH; 2. H2O2, NaOH
B) Hg2+, H2SO4, H2O
C) 1. O3; 2. (CH3)2S
D) 1. CH3MgBr; 2. CO2
E) 1. H2, Ni; 2. Na2Cr2O7, H2SO4
Answer: B
Diff: 2
Section: 18.7
35) Oxidation of a 1° alcohol with chromic acid results in the production of __________.
A) an ester
B) a ketone
C) an aldehyde
D) an ether
E) none of the above
Answer: E
Diff: 2
Section: 18.7
36) Oxidation of a 2° alcohol with chromic acid results in the production of __________.
A) an ester
B) a ketone
C) an aldehyde
D) an ether
E) none of the above
Answer: B
Diff: 2
Section: 18.7
37) Oxidation of a 3° alcohol with chromic acid results in the production of __________.
A) an ester
B) a ketone
C) an aldehyde
D) an ether
E) none of the above
Answer: E
Diff: 2
Section: 18.7
8
38) Oxidation of a 1° alcohol with pyridinium chlorochromate results in the production of
__________.
A) an ester
B) a ketone
C) an aldehyde
D) an ether
E) none of the above
Answer: C
Diff: 2
Section: 18.7
39) Which of the following reactions will not yield a ketone product?
A)
B)
C)
D)
E)
Answer: A
Diff: 2
Section: 18.7
40) Provide the major organic product which results when PhCHO is treated with the following
sequence of reagents: 1. CH3CH2MgBr; 2. H3O+; 3. Na2Cr2O7, H2SO4.
Answer: PhCOCH2CH3
Diff: 1
Section: 18.7
9
41) Propose a synthesis of 3-heptanone from propanal.
Answer:
1. CH3CH2CH2CH2MgBr, Et2O
2. H3O+
3. Na2Cr2O7, H2SO4
Diff: 2
Section: 18.7
42) Beginning with sodium acetylide (NaCCH), propose a three-step synthesis of hexanal.
Answer:
1. CH3CH2CH2CH2Br
2. Sia2BH
3. H2O2, NaOH
Diff: 3
Section: 18.7
43) Provide the major organic product which results when PhCHOHCH3 is treated with PCC.
Answer: PhCOCH3
Diff: 1
Section: 18.7
44) By which single reaction can benzene be readily converted into acetophenone?
Answer: CH3COCl, AlCl3 - a Friedel-Crafts acylation reaction
Diff: 2
Section: 18.7
45) Provide the major organic product which results when pentanal is subjected to the following
sequence of steps: 1. PhMgBr; 2. H3O+; 3. PCC
Answer: PhCOCH2CH2CH2CH3
Diff: 2
Section: 18.7
46) Name the compound generated when ethylbenzene is treated with CO, HCl, AlCl3, and
CuCl.
Answer: p-ethylbenzaldehyde
Diff: 2
Section: 18.7
47) Name the compound generated when 1-methylcyclohexene is subjected to O3 followed by
dimethyl sulfide.
Answer: 6-oxoheptanal
Diff: 3
Section: 18.7
10
48) Which of the following carbonyl compounds may be made from 1,3-dithiane?
1) methyl vinyl ketone
2) 2-pentanone 3) 3,3-dimethyl-2-butanone 4) 2-phenylethanal
A) 1 & 4
B) 2 only
C) 2 & 3
D) 2 & 4
Answer: D
Diff: 2
Section: 18.8
49) What compound is produced when 1,3-dithiane is subjected to the following sequence of
reagents:
1. n-BuLi 2. CH3CH2Br 3. n-BuLi 4. (CH3)2CHCH2CH2I 5. HgCl2, H3O+?
Answer: CH3CH2COCH2CH2CH(CH3)2
Diff: 3
Section: 18.8
50) Why is (CH3)3CCHO not available via a 1,3-dithiane based synthesis?
Answer: A dithiane based synthesis of (CH3)3CCHO would require the dithiane anion to react
with (CH3)3CBr in an SN2 process. Tertiary halides do not undergo SN2 reactions because they
are excessively hindered.
Diff: 3
Section: 18.8
51) What compound is produced when 1,3-dithiane is subjected to the following sequence of
reagents: 1. n-BuLi 2. (CH3)3CCH2CH2CH2I 3. HgCl2, H3O+?
Answer: (CH3)3CCH2CH2CH2CHO
Diff: 3
Section: 18.8
52) Beginning with 1,3-dithiane, propose a synthesis of 4-heptanone.
Answer:
1. BuLi
2. CH3CH2CH2Br
3. BuLi
4. CH3CH2CH2Br
5. HgCl2, H3O+
Diff: 2
Section: 18.8
11
53) Provide the major organic product which results in the reaction shown below.
Answer:
Diff: 2
Section: 18.8
54) Provide the major organic product which results when PhCH2CH2CO2H is treated with
excess butyllithium followed by H3O+.
Answer: PhCH2CH2COCH2CH2CH2CH3
Diff: 1
Section: 18.9
55) Treatment of a nitrile with a Grignard reagent followed by hydrolysis results in __________.
A) an ester
B) a ketone
C) an aldehyde
D) an ether
E) an alcohol
Answer: B
Diff: 3
Section: 18.10
56) Provide the major organic product of the reaction shown below.
Answer:
Diff: 2
Section: 18.10
12
57) Complete the following reaction by filling in the necessary reagents.
Answer:
Diff: 3
Section: 18.10
58) How might one prepare 4-heptanone from CH3CH2CH2CN in two steps?
Answer:
1. CH3CH2CH2MgBr
2. H3O+
Diff: 2
Section: 18.10
59) Which of the following describes a synthesis of an aldehyde?
A) hydrogenation of an acid chloride using Pd/BaSO4/S as a poisoned catalyst
B) reaction of a primary alcohol with Na2Cr2O7
C) reaction of a ketone with ozone
D) treatment of an alkene with Sia2BH
E) none of the above
Answer: A
Diff: 1
Section: 18.11
13
60) Which series of reactions described below, if any, will result in the formation of 2methylpentan-3-one starting with 1-propanol?
A) 1. (CH3)2CHMgBr/ diethyl ether
2. dilute H3O+
3. PCC
B) 1. Na2Cr2O7/H2SO4 and heat
2. SOCl2
3. 2 (CH3)2CHMgBr/ diethly ether
4. H3O+
C) 1. Na2Cr2O7/H2SO4 and heat
2. (CH3)2CHMgBr/ diethyl ether
3. dilute H3O+
4. LiAlH4
D) 1. PCC
2. (CH3)2CHLi/ diethyl ether
3. dilute H3O+
4. Na2Cr2O7/H2SO4 and heat
E) none of the above
Answer: D
Diff: 2
Section: 18.11
61) Provide the major organic product which results when (CH3)2CHCH2CH2COCl is treated
with LiAlH[OC(CH3)3]3.
Answer: (CH3)2CHCH2CH2CHO
Diff: 2
Section: 18.11
62) What organic compound is generated when PhCOCl is treated with (CH3CH2CH2)2CuLi?
Answer: PhCOCH2CH2CH3
Diff: 2
Section: 18.11
63) When the carbonyl group of a neutral ketone is protonated,:
A) the resulting species becomes more electrophilic.
B) the resulting species is activated toward nucleophilic attack.
C) subsequent nucleophilic attack on the resulting species is said to occur under acid-catalyzed
conditions.
D) the resulting species has a positive charge.
E) all of the above.
Answer: E
Diff: 1
Section: 18.12
14
64) Consider the equilbrium of each of the carbonyl compounds with HCN to produce
cyanohydrins. Which is the correct ranking of compounds in order of increasing Keq for this
equilbrium?
A) H2CO < cyclohexanone < CH3CHO < 2-methylcyclohexanone
B) CH3CHO < 2-methylcyclohexanone < cyclohexanone < H2CO
C) cyclohexanone < 2-methylcyclohexanone < H2CO < CH3CHO
D) cyclohexanone < 2-methylcyclohexanone < CH3CHO < H2CO
E) 2-methylcyclohexanone < cyclohexanone < CH3CHO < H2CO
Answer: E
Diff: 2
Section: 18.12
65) The following compound has been found effective in treating pain and inflammation (J. Med.
Chem. 2007, 4222). Which sequence correctly ranks each carbonyl group in order of increasing
reactivity toward nucleophilic addition?
A) 1 < 2 < 3
B) 2 < 3 < 1
C) 3 < 1 < 2
D) 1 < 3 < 2
Answer: B
Diff: 2
Section: 18.12
66) What reagent can be used to convert benzophenone into triphenylmethanol?
Answer: PhMgBr followed by acidic work up
Diff: 1
Section: 18.12
67) Draw two major resonance forms of the cation which results when cyclohexanone's carbonyl
group is protonated.
Answer:
Diff: 2
Section: 18.12
15
68) Rank the following compounds in order of their propensity to become a hydrate in water (ie,
start with the least easy to hydrate: CH3COCH2CH3, H2CO, Cl3CCHO, and CH3CH2CHO.
Answer: CH3COCH2CH3 < CH3CH2CHO < H2CO < Cl3CCHO
Diff: 2
Section: 18.12
69) Provide the major organic product of the reaction shown below.
Answer:
Diff: 2
Section: 18.12
70) Provide the major organic product of the reaction shown below.
Answer:
Diff: 2
Section: 18.12
71) Provide the major organic product of the reaction shown below.
Answer:
Diff: 2
Section: 18.12
16
72) Provide the structure of the hydrate of cyclopentanone.
Answer:
Diff: 1
Section: 18.12
73) Propose a synthesis of 4-phenylbutan-2-ol from 3-phenylpropanal.
Answer:
1. CH3MgBr
2. H3O+
Diff: 2
Section: 18.12
74) Provide a detailed, stepwise mechanism for the base-catalyzed hydration of 2-butanone.
Answer:
Diff: 2
Section: 18.12
75) Propose a synthesis of 3-methylhept-4-yn-3-ol from but-1-yne.
Answer:
1. NaNH2
2. CH3COCH2CH3
3. H3O+
Diff: 3
Section: 18.12
76) Why are the equilibrium constants for hydration of aldehydes typically greater than those of
ketones?
Answer: The carbonyl group of an aldehyde is stabilized by only one electron donating alkyl
group. Therefore, its carbonyl group has more partial positive charge than that of a ketone.
Aldehydes are more electrophilic and less stable than ketones.
Diff: 3
Section: 18.12
17
77) An ylide is a molecule that can be described as a:
A) carbanion bound to a negatively charged heteroatom.
B) carbocation bound to a positively charged heteroatom.
C) carbocation bound to a carbon radical.
D) carbocation bound to a diazonium ion.
E) carbanion bound to a positively charged heteroatom.
Answer: E
Diff: 1
Section: 18.13
78) Provide the major organic product of the reaction shown below.
Answer:
Diff: 2
Section: 18.13
79) Provide the necessary reagents to complete the following transformation.
Answer:
Diff: 3
Section: 18.13
18
80) Through what sequence of steps can toluene be converted into PhCH2PPh3+Br-?
Answer:
1. Br2, hν or NBS
2. Ph3P
Diff: 1
Section: 18.13
81) Provide the single reagent necessary for the conversion of cyclobutanone to the compound
shown below.
Answer: CH3
Diff: 1
Section: 18.13
3
82) Provide the structure of the major organic product which results when CH3CH2I is treated
with PPh3 and the resulting salt is reacted with one equivalent of butyllithium.
Answer: CH3CH=PPh3
Diff: 1
Section: 18.13
83) Provide the preferred reagent pair to synthesize 3-ethylpent-2-ene via a Wittig reaction.
Answer: CH3CH2COCH2CH3 and CH3CH=PPh3
Diff: 2
Section: 18.13
84) Propose a Wittig reaction-based synthesis of hex-3-ene using propene as the only carbon
source and any other reagents necessary.
Answer: Prepare hex-3-ene from propene as follows:
1. BH3∙THF
2. H2O2, NaOH
3. PCC
4. CH3CH2CH=PPh3
Prepare the ylide (CH3CH2CH=PPh3) from propene as follows:
1. HBr, peroxides
2. PPh3
3. BuLi
Diff: 3
Section: 18.13
19
85) Provide the structure of the compound which results when HCN adds to pentanal.
Answer:
Diff: 2
Section: 18.15
86) Provide the major organic product of the reaction shown below.
Answer:
Diff: 2
Section: 18.15
87) Which of the following is also known as a Schiff base?
A) an imine
B) a cyanohydrin
C) a hydrate
D) sodium hydroxide
E) an aldehyde
Answer: A
Diff: 2
Section: 18.16
88) Give the structure of the acyclic compound from which the following imine was formed.
Answer:
Diff: 2
Section: 18.16
20
89) Provide the major organic product of the following reaction.
Answer:
Diff: 2
Section: 18.16
90) Provide the major organic product of the reaction shown below.
Answer:
Diff: 2
Section: 18.16
91) Provide the major organic product of the reaction of aniline with 3-pentanone.
Answer:
Diff: 2
Section: 18.16
21
92) Provide a detailed, stepwise mechanism for the acid-catalyzed condensation reaction
between benzaldehyde and methylamine.
Answer:
Diff: 3
Section: 18.16
93) Conversion of aldehydes and ketones to imines is an acid-catalyzed process. Explain why
this conversion is actually hindered by the presence of too much acid.
Answer: At very low pH, much more of the amine is protonated and can no longer function as a
nucleophile.
Diff: 3
Section: 18.16
94) When H2NCH2CH2CH2CH2COCH3 is heated in the process of an acid catalyst, a reaction
occurs. The product has the formula C6H11N. Provide the structure of this product.
Answer:
Diff: 3
Section: 18.16
95) Provide the major organic product of the following reaction.
Answer:
Diff: 2
Section: 18.17
22
96) Provide the major organic product of the reaction shown below.
Answer:
Diff: 2
Section: 18.17
97) Provide the structure of the semicarbazone derivative of 3-pentanone.
Answer:
Diff: 3
Section: 18.17
98) Provide the structure of the compound which reacts with a ketone to form its hydrazone
derivative.
Answer: H2NNH2
Diff: 1
Section: 18.17
99) Provide the structure of cyclohexanone oxime.
Answer:
Diff: 2
Section: 18.17
100) Provide the structure of the major organic product which results when benzaldehyde reacts
with hydroxylamine in the presence of acid.
Answer:
Diff: 2
Section: 18.17
23
101) Provide a detailed, stepwise mechanism for the acid-catalyzed condensation reaction
between cyclohexanone and H2NOH.
Answer:
Diff: 3
Section: 18.17
102) Acetals will react with:
A) H3O
B) NaOCH3
C) PhLi
D) CH3CH2MgBr
E) NaBH4
Answer: A
Diff: 1
Section: 18.18
24
103) What would be the product of the following reaction?
A)
B)
C)
D)
E)
Answer: A
Diff: 2
Section: 18.18
25
104) Why do acetal-forming reactions that use ethylene glycol have more favorable equilbrium
constants than those using methanol?
A) Ethylene glycol reacts more rapidly.
B) They are more favorable on entropy grounds.
C) They are more favorable on enthalpy grounds.
D) Ethylene glycol is acidic and catalyzes the reaction.
E) The ethylene acetal can serve as a protecting group.
Answer: B
Diff: 3
Section: 18.18
105) Provide the major organic product of the reaction shown below.
Answer:
Diff: 2
Section: 18.18
106) Provide the major organic product of the reaction shown below.
Answer:
Diff: 2
Section: 18.18
107) When HOCH2CH2CH2CH2COCH2CH2CH2CH2OH is heated in the presence of an acid
catalyst, a reaction occurs. This product has the formula C9H16O2. Provide the structure of this
product.
Answer:
Diff: 3
Section: 18.18
26
108) Predict the product of the following reaction.
Answer:
Diff: 3
Section: 18.18
109) Provide the structure of the diethyl acetal of butanal.
Answer: CH3CH2CH2CH(OCH2CH3)2
Diff: 2
Section: 18.18
27
110) Which series of reactions described below will result in the formation of compound A,
starting with compound B?
A) 1. HO-(CH2)2-OH /trace H3O+
2. DMSO (COCl2)/Et3N, CH2Cl2
3. MgBr-(CH2)2-CH3/diethylether
4. work-up with H3O+
B) 1. PCC
2. SOCl2
3. LiCu-((CH2)2-CH3)2
4. work-up with H3O+
C) 1. Na2Cr2O7/H2SO4
2. SOCl2
3. 2 MgBr-(CH2)2-CH3/diethylether
4. work-up with H3O+
D) both A and B
E) both B and C
Answer: A
Diff: 2
Section: 18.19
28
111) Provide a detailed, stepwise mechanism for the acid-catalyzed reaction of 2-butanone with
ethylene glycol (HOCH2CH2OH) to produce an acetal.
Answer:
Diff: 3
Section: 18.19
112) Propose a sequence of steps to carry out the following conversion.
Answer:
1. HOCH2CH2OH, H+
2. NaNH2
3. CH3I
4. H3O+
5. NaBH4 or LiAlH4
Diff: 3
Section: 18.19
29
113) Propose a sequence of steps to carry out the following conversion.
Answer:
1. HOCH2CH2OH, H+
2. CH3CH2CH2MgBr
3. H3O+
Diff: 2
Section: 18.19
114) Which would be more appropriate as the reduction in the following sequence, a
Clemmensen or a Wolff-Kishner? Explain.
Answer: Wolff-Kishner. The acidic conditions of the Clemmensen would remove the protecting
group causing reduction of the aldehyde as well.
Diff: 3
Section: 18.19
115) What intermediate occurs when a ketone undergoes a Wolff-Kishner reduction?
A) a cyanohydrin
B) a hydrated aldehyde
C) a carboxylate
D) a semicarbazone
E) a hydrazone
Answer: E
Diff: 2
Section: 18.21
116) The reagent which converts a carbonyl group of a ketone into a methylene group is:
A) Na, NH3, CH3CH2OH
B) LiAlH4
C) NaBH4, CH3CH2OH
D) Zn(Hg), conc. HCl
E) LiAlH[OC(CH3)3]3
Answer: D
Diff: 2
Section: 18.21
30
117) Provide the major organic product of the following reaction.
Answer:
Diff: 2
Section: 18.21
31