In real exam the format may be different. It may have all multiple
choice or all show your work type of questions.
Sample Exam 2 (ch.5-8)
Part I: Multiple choice: Please bubble your correct answer in scantron
1. Consider the following structures, identify the type of isomers.
H
CH3
H3C
Br
H
Br
H
CH3
and
H
H3C
RR
A. identical
Br
Br
B. Constitutional isomers
SS
C. diastereoisomers
D. enantiomers
2. What is the correct absolute configuration for the following compoud?
H
A. R
B. S
C. achiral
D. cannot be determined
3. The (+) enantiomer of a compound has an observed optical rotation of 1.75 degrees when
measured in a one dm tube at a concentration of 0.3 g/ 15 ml. What is the specific rotation,
[], of the molecule?
[] = /l x c = 1.75/1x 0.3g/15 ml = 1.75 * 15/.3 =
A. 30 o
B. 45 o
C. 87.5o
D. 1.75 o
4. What is the correct configuration for the following compound, 3-bromo-2-butanol?
CH3
Br
H
H
OH
CH3
A. (2R,3S)
B. (2S,3S)
C. (2R,3R)
D. (2S,3R)
5. Species with unpaired electrons are called ___________________ .
A. molecular ions
B. free atoms
C. radicals
D. electrophiles
6. Identify the type of the following reaction:
Br
Br2 / H2O
OH
A. elimination
B. substitution
C. addition
D. rearrangement
7. Consider the following reaction. Which species is the nucleophile?
..
O:
..
..
O:
+
(I)
: CN
CN
( II)
A. I only
( III )
B. II only
C. III only
D. none of these
8. This process occurs when both bonding electrons remain with one product fragment.
A. homolytic bond breaking
C. homolytic bond formation
B. heterolytic bond breaking
D. radical formation
9. How many degree of unsaturation are in Valium (diazepam), C16H13N2OCl ?
A. 10
B. 11
C. 7
D. 12
10. Provide the proper IUPAC name for the alkene shown below.
CH3 – CH = CH – CH2 – CH3
A. n- pentane
B. 3-pentene
C. 2- pentene
11. What is the acceptable structure for 1,2-dimethylcyclohexene?
A.
B.
C
D.
D. 2- pentyne
12. What two atomic orbitals or hybrid atomic orbitals overlap to form the C = C bond in
ethene?
B. sp2 – sp2
A. sp-sp
C. sp-sp2
D. sp3-sp3
C. - CH3
D. – OCH3
13. Which of the following has the highest priority?
A. –CN
B. –OH
14. Which of the following alkenes is most stable?
A.
B.
C.
D.
15. Addition of HBr to 2-butene is called ___________________.
A. Hydroboration hydration
C. Hydrohalogenation
B. Hydrogenation
D. Hydration
16. What is the IUPAC name of following compound?
CH3
CH3
C
H
C
CH3
C
H
A. 3,5-dimethyl-3,4-hexadiene
B. 2,4-dimethyl-2,4-hexadiene
C
CH3
B. 2,4-dimethyl-2,4-hexaene
D. 1,1,3-trimethyl-1,3-pentadiene
17. Provide the reagents necessary to complete the following transformation.
OH
O
CO2
A. KOH /ethanol
B. KMnO4 /H3O+
18. bromination of an alkene occurs with:
A. anti stereochemistry
C. syn stereochemistry
+
C. CH2I2 /Zn(Cu)
B. cis stereochemistry
D. non Markovnikov addition
D. non of these
19. Addition of water to 2-butene is called ___________________.
A. Hydroboration hydration
C. Hydrohalogenation
B. Hydrogenation
D. Hydration
20. What is the major product of the following reaction?
OH
H2SO4 /heat
CH3
A.
D.
C.
B.
CH3
CH2
CH3
21. Compounds containing two or more chiral centers, but are achiral overall, are called:
A. enantiomers compounds
C. diastereomers
B. meso compounds
D. reference compound
22. How many chiral centers does the following compound have?
CH3 – CHBr – CHCl – CH2 – CH3
A. 1
B. 2
C. 3
D. 4
Part II: Show your work
1. Naming and structures
a) Give the IUPAC name of the following compounds:
Br
Br
H
H3C
H
CH3
CH2CH3
CH3
H
Br
I
I
III
IV
I. ___________________________________________
II. __________________________________________
III. __________________________________________
IV. ___________________________________________
b) Draw structures corresponding to the following systematic names;
(2Z)- 3-methyl-2-pentene
1,5-dimethylcyclopentene
(S)-2-hydroxybutane
(2R,3S)-2,3-dihydroxybutane
2.Mechanism:
a) Propose a mechanism to account for the shown reaction. Please show the structures of
the intermediates and using curved arrows to indicate electron flow in each step.(Rearrangement
may occur)
CH3
CH3 - C - CH = CH2
ether
+ HBr
CH3
b) Draw one enantiomer, and one diastereomer of the following compound.
OH
H
Br
CH3
H
CH2CH3
3. Synthesis:
Show by a series of reactions how could you prepare the following compounds from the
indicated starting compounds. Be sure to clearly indicate the reagents used in each step.
a.
b.
4. Complete the following reactions.
CH3
a)
Br2 /H2O
CH3 - CH - CH = CH2
H2
CH3
b)
Pd /C
HBr /ether
c)
1) BH3, THF
d)
2) H2O2 , OH
Br
e)
f)
KOH/ ethanol
2 - hexene
KMnO4
H3O
g)
2 moles H2
CH2
Pd /C
h)
i)
j)
Br2 / CCl4
CH2I2 / Zn(Cu)
1) O3
2) Zn / H3O
5. Bonus Question
How many alkene products, including E,Z isomers, might be obtained by dehydration of 3methyl-3-hexanol with aqueous sulfuric acid? Draw all the structures.
Key:
Part I: Multiple choice
1-D, 2-A, 3-C, 4-B, 5-C, 6-C, 7-B, 8-B, 9-B, 10-C, 11-B, 12-B, 13-D,
14-A, 15-C, 16-B, 17-B, 18-A, 19-D, 20-B, 21-B, 22-B,
Part II: Show your work:
1. Naming and structures
a). Give the IUPAC name of the following compounds:
Br
Br
H
H3C
H
CH3
CH2CH3
I
CH3
H
Br
II
III
IV
I. (R)-2-Bromobutane
II. (2S,3S)-2,3-dibromobutane
III. 3- Methylcyclohexene or 3-Methylcyclohex-1-ene
IV. (3Z)-3,5-Dimethyl-3-hexene
b). Draw structures corresponding to the following systematic names;
(2Z)- 3-methyl-2-pentene
1,5-dimethylcyclopentene
H
CH3
CH3
C=C
CH3
CH3-CH2
CH3
(S)-2-hydroxybutane
(2R,3S)-2,3-dihydroxybutane
CH3
HO
HO
C2H5
H3C
H
H
H
OH
CH3
2.Mechanism:
a) Propose a mechanism to account for the shown reaction. Please show the structures of
the intermediates and using curved arrows to indicate electron flow in each step.(Rearrangement
may occur)
CH3
CH3
ether
CH3 - C - CH = CH2
+ HBr
CH3
CH3 - C - CH - CH3
methide
shift
CH3
3 carbocation intermediate
:Br
CH3
:Br
CH3 - C - CH - CH3
CH3
Br
CH3 - C - CH - CH3
CH3
2 carbocation intermediate
CH3
Br
CH3
CH3 - C - CH - CH3
CH3
b)
Draw one enantiomer, and one diastereomer of the following compound.
OH
H
CH3
Diastereomer
OH
OH
CH3
H
H
Br
H
Br
Enantiomer
CH2CH3
CH3
H
Br
H
CH2CH3
CH2CH3
3.Synthesis:
Show by a series of reactions how could you prepare the following compounds from the
indicated starting compounds. Be sure to clearly indicate the reagents used in each step.
a)
Cl
Cl
CHCl3 /KOH
Cl2 /light
Cl
KOH /ethanol
b)
4. Complete the reactions
CH3
a)
CH3
Br2 /H2O
CH3 - CH - CH = CH2
CH3 - C - CH2 - CH2Br
OH
H2
CH3
b)
CH3
Pd /C
HBr /ether
c)
Br
1) BH3, THF
d)
OH
2) H2O2 , OH
Br
e)
f)
KOH/ ethanol
2 - hexene
KMnO4
CH3 - CH2 - CH2 - C OOH
+ CH3 - COOH
H3O
g)
2 moles H2
CH2
CH3
Pd /C
H
h)
Br2 / CCl4
Br
Br
i)
j)
CH3
CH2I2 / Zn(Cu)
O
O
O3
H3O
CH3 C - (CH2)4 - C -H
5. Bonus Question
How many alkene products, including E,Z isomers, might be obtained by dehydration of 3methyl-3-hexanol with aqueous sulfuric acid? Draw all the structures.