Part II: Problems related to topic 1 (30 points)
Please provide answers for all multiple choice questions on a Scantron card.
1. A correct IUPAC name of the compound below is:
Br
a. 1-Bromo-1-methyl-2,5-cyclohexadiene
c. 6-Bromo-6-methyl-1,4-cyclohexadiene
e. None of these
b. 3-Bromo-3-methyl-1,4-cyclohexadiene
d. 2-Bromo-2-methyl-1,3-cyclohexadiene
2. Arrange the following carbocations in the order of expected increasing stability:
I
a. II < IV < III < I
d. I < III < II < IV
II
III
IV
b. II < IV < I < III
e. IV < II < III < I
c. I < III < IV < II
3. Treatment of 4-methylcyclohexene with N-bromosuccinimide in CCl4 would yield mainly:
Br
a.
b.
c.
d. a mixture of
b and c
Br
e. a mixture of
a, b, and c
Br
4. The allyl radical has how many electrons in bonding molecular orbital(s)?
a. 0
b. 1
c. 2
d. 3
e. 4
5. Arrange these hexadienes in order of expected decreasing stability:
I
II
a. II > IV > III > I
d. I > III > IV > II
III
IV
b. IV > II > III > I
e. III > I > II > IV
c. IV > II > I > III
6. Which of the following is not a proper resonance structure for 2-methyl-cyclohexa-1,3-diene?
a.
b.
c.
d.
e. all are correct
7. The diagram below, which describes the fate of intermediate K in a reversible reaction, implies:
Intermediate K has a short life time.
The more stable product forms more rapidly.
The less stable product forms more rapidly.
Product P2 will predominate at equilibrium.
Both, c and d are correct.
potential energy
a.
b.
c.
d.
e.
K
P1
P2
reaction coordinate
8. Which diene and dienophile would you choose to synthesize compound Q?
CN
Q
CN
CN
CN
a.
and
b.
and
CN
CN
c.
and
e.
and
NC
CN
d.
CN
and
CN
NC
CN
9. Which of the following comounds is 2-bromo-4-nitroanisole?
Br
Br
NH 2
a.
Br
b.
NO 2
c.
NO 2
OCH3
Br
d.
Br
H 3CO
e.
H 2N
NH 2
NO 2
NO 2
NO 2
10. On the basis of molecular orbital theory and Hückels rule, which of the following should be aromatic?
H
N
I
II
III
N
H
O
IV
V
N
VI
a. II, V, VI, IX, X
d. I, II, V, VIII, X
VII
VIII
b. III, IV, VI, VII
e. I, V, VIII
IX
H
H
X
c. II, IV, V, VIII, X
Part III: Review of CHEM 2311 (54 points):
11. Based on VSEPR theory, which of the following would not have a trigonal planar shape?
a. H2CO
b. BrF3
c. BCl3
d. SO3
e. CH3
+
12. Which of the following molecules has only sp-hybridized atoms?
a. I3
––
b. CO2
c. CO
d. Br2
e. N3
––
13. Which of the following species is/are not a resonance form(s) of the species in the box?
OH
OH
OH
OH
a.
OH
b.
OH
OH
OH
OH
c.
OH
OH
d.
OH
e.
14. Classify the following pair of molecules A and B in terms of their isomer-relationship:
H
HO
A
H
HO
B
O
O
O
a. enantiomers
e. regioisomers
O
b. diastereomers
c. identical
d. constitutional isomers
15. Which staggered Newman projection(s), looking down the C-2——C-3 bond (C-2 in front and C-3 in
back), illustrates (2S,3R)-3-methylpent-4-en-2-ol?
H 3C
I
HO
CH 3
H
H
CH=CH2
a. I and V
HO
CH=CH2
H
H
CH 3
II
CH 3
b. IV
c. V
H 3C
III
H
CH 3
H
H
IV
OH
CH=CH2
HO
d. II and III
CH 3
CH 3
H
CH=CH2
b. 2-methylhexane
e. 4-methylpent-2-ene
H
e. none of these
16. Which of the following compounds has 1º, 2º, 3º and 4º carbon atoms?
a. heptane
d. 2,2,3-trimethylpentane
V
H
c. 2,2-dimethylhexane
CH 3
CH 3
OH
CH=CH2
17. The diterpene (+)-Phomactin A is an antagonist of the platelet-activating factor. Phomactin A has how
many stereogenic centers?
O OH
H 3C
OH
O
H 3C
Phomactin A
CH 3
CH 3
a. 2
b. 4
c. 5
d. 6
e. 7
18. Which of the following molecules is a meso compound?
I
HO
CH 3
H
HO
H
OH
II
CH 3
a. III
b. II
HO
H
H 3C
H
III
CH 3
c. II and V
H 3C
CH 3
OH
H 3C
OH
OH
IV
H
d. I and IV
H
CH 3
H
CH 3
OH
V
H 3C
H 3C
CH 3
CH 3
OH
OH
e. none of these
19. What are the correct stereochemical descriptors for (––)-menthol, the main stereoisomer of menthol
occuring in nature?
(–– )-menthol
HO
a. 1S,2R,5S
b. 1R,2S,5R
c. 1R,3S,6R
d. 1S,3R,6S
e. the molecule is not chiral
20. Which of the following molecules are not chiral?
HO
H
HO
CH2OH
H
OH
H
CH2OH
I
a. II, III and V
H
H
Br
Br
CH 3
O
CH 3
Ph
II
b. II and IV
O
Fe
Ph
III
c. I and IV
Cl
O
IV
V
d. I, IV, and V
e. all of these are chiral
d. BCl3
e. all of these are Lewis acids
21. Which of the following is not a Lewis acid?
a. AlCl3
b. FeBr3
c. PF6
––
Cl
22. Which of the following compounds is not polar?
b. POCl3
a. SO3
c. DMSO
d. acetonitrile
e. acetone
23. Which of the following will likely not act as a nucleophile?
Br
a. H 3C
b.
CH 3
c.
d.
OH
e.
H
Al
H
H
H
24. In the structure shown below, rank the hydrogen atoms from highest to lowest in acidity.
a) Ha>Hb>Hc>Hd
Hb
O
Ha
Hc
O
b) Hd>Hc>Ha>Hb
Hd
c) Hc>Hd>Hb>Ha
O
d) Hd>Hc>Hb>Ha
e) Ha>Hb>Hd>Hc
25. Which of the following solvents is considered a protic solvent?
a. diethyl ether
b. acetonitrile
c. ethyl acetate
d. benzene
e. butanol
26. What is the major product for the following reaction?
1. NaH
?
OH
2. D 2O
D
a.
D
OD
b.
D
OD
D
c.
d. D
OD
D
OD
e. D
27. What is the major organic product obtained from the following set of reactions?
NaNH 2
H 3C
Br
H
a. (E)-5-methyl-2-hexene
d. 2-methylhexane
H2
?
Pd/CaCO 3
(Lindar's cat.)
b. (Z)-5-methyl-2-hexene
e. 2,4-dimethylpentane
c. 5-methyl-2-hexyne
28. Which would be the best choice of reagents to accomplish the following transformation?
Br
a. HBr, peroxides
c. PBr3
e. NBS, H2O
b. HBr (no peroxides)
d. Br2 in CCl4
OH