CHEMISTRY 213
EXAM 1
Fri., April 18, 2003
Answer all 18 questions (150 pts).
Name
.
Answer Key
1. (3) True or False. The compound shown would
lose CO2 on treatment with H 3 O+ and heat.
COCH3
CO2Ph
2. (3) True or False. The hydrogens  to the carbonyl of an ester are less acidic than those  to a ketone.
3. (3) True or False. The compound shown is malonic ester.
O
O
Et
OEt
4. (7.5) For each of the following reactions, state whether the step shown is an addition, elimination,
rearrangement, or substitution.
O
a)
O
substitution
OMe
O
b)
NHMe
O
elimination
Ph Se
O
O
c)
O
substitution
5. (12) In each of the following molecules, identify all the acidic hydrogens with pKa values <25. Note, you
may have to draw in the appropriate hydrogen atoms. Additionally, give the approximate pKa value for
each proton you have indicated.
a)
b)
O
O
H pKa = 10
O
O
H
pKa = 20
HO pKa = 5
O
c)
HO
H
pKa = 20
pKa = 17
H
pKa = 20
6. (7) Draw two other resonance forms for the following anion.
O
O
O
7. (38) Provide the structures of the major organic products expected, or provide the reactants and / or
reagents necessary to effect the following transformations:
a)
COOH
COOH
heat
COOH
b)
O
excess NaOH
Ph
Ph
excess I 2
O
c)
O
H+
O
1) Br 2 , PBr3
HO
2) H2O
HO
Br
CO2Me
d)
OH
CO2Me
1) LiOMe
CO2Me
CO2 Me
2) 1-bromo-3methylbutane
H3O+, heat
COOH
e)
O
Ph
O
O
O
KOEt
Ph
Ph
O
OEt
+
O
Ph
f)
O
OH
1) 2 MeMgCl
Cl
2) H+
O
g)
1) LDA
O
2)
Br
8. (4.5) Assign the relative reactivity of each of the following to nucleophiles (use #1 for most reactive to #3
for the least).
O
O
O
O
NH
H3 C
3
CH3
O
O
2
CH3
CH3
1
9. (9) Answer the following questions related to the malonic ester synthesis.
a) What solvent would be used for the reaction of malonic ester with NaOEt ?
Ethanol
b) Why can malonic acid itself (HOOCCH2COOH) not be used as the starting material ?
The base would react with the carboxylic acid protons rather than the alpha proton
c) Why can NaOH not be used as a base for the reaction with malonic ester ?
The hydroxide ion would attack the C=O carbon and displace RO10. (3.5) Explain briefly but clearly why LDA would never be used in ethanol as solvent.
LDA is a very strong base and would easily abstract the alcohol proton, generating
Alkoxide anion and forming diethylamine
11. (3.5) Explain briefly but clearly why it is necessary to use an acid catalyst for the hydrolysis of an
amide.
Water would not be a strong enough nucleophile to displace the amine anion from the amide. If an
acid
catalyst is used, the amide becomes a better electrophile and the leaving group is improved drastically,
becoming a neutral amine rather than its anion
12. (9) State whether each of the following normally would act as a nucleophile or electrophile. You need
not explain your answer.
a)
b)
c)
O
Al
KOCH2CH2CH3
H
nucleophile
electrophile
nucleophile
13. (15) From the list given, choose the best reagent for each transformation shown. Write the appropriate
letter above the reaction arrow. It is possible to use the same reagent more than once.
A. NaCN then H2 / Pd
E. NaCN then H3O+
C. NaBH4
D. Me2CuLi then H+
G. LiAlH4 then H3O+
H. H3O+
B. NaOH, Br2
F. MeMgBr then H3O+
H
CONHCH3
COOH
H
CO 2CH 3
COOH
D
COCl
COCH3
G
PhCH2CONHCH3
PhCH2Br
PhCH2CH2NHCH3
E
PhCH 2CO 2H
14. (10) In each of the following examples, draw the 2 key starting materials (not bases or solvents) required
to form the products shown by C-C forming reactions.
a)
from a nitrile, Grignard,
+
then H 3 O
Ph
O
Ph
C
N
+
EtMgBr
O
b)
OH
Br
+
H2C(CO2 Me)2
15. (4) The first step of the hydrolysis of a nitrile under basic conditions (HO-, water) is attack by hydroxide
on the C of the CN, with breaking of the CN pi bond. What is the second step?
Attack by the resultant nitrogen anion upon the H of water
16. (12) Show the first complete step of the arrow-pushing mechanism for each of the following:
O
a)
OEt
NaOMe
MeOH
b)
OH
Li
NiPr2
H
Li
NiPr2
O
H
c)
O
17. (3) True or False. Treatment of malonic ester with NaOMe gives 100% of the corresponding anion.
18. (3) True or False. Treatment of acetone with NaOMe gives 100% of the corresponding anion.