Chem 2423
Sample Exam 2 (ch.5-8)
Part I: Multiple choice: Please bubble your correct answer in scantron
1. Species with unpaired electrons are called ___________________ .
A. molecular ions
B. free atoms
C. radicals
D. electrophiles
2. Identify the type of the following reaction:
Br
Br2 / H2O
OH
A. elimination
B. substitution
C. addition
D. rearrangement
3. Consider the following reaction. Which species is the nucleophile?
..
O:
..
..
O:
+
(I)
A. I only
: CN
CN
( II)
B. II only
( III )
C. III only
D. none of these
4 This process occurs when both bonding electrons remain with one product fragment.
A. homolytic bond breaking
C. hemolytic bond formation
B. heterolytic bond breaking
D. radical formation
5. How many degree of unsaturation are in Valium (diazepam) , C16H13N2OCl ?
A. 10
B. 11
C. 7
D. 12
6. Provide the proper IUPAC name for the alkene shown below.
CH3 – CH = CH – CH2 – CH3
A. n- pentane
B. 3-pentene
C. 2- pentene
7. What is the acceptable structure for 1,2-dimethylcyclohexene?
D. 2- pentyne
D.
C
B.
A.
8. 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
9. Which of the following has the highest priority?
A. –CN
B. –OH
10. Which of the following alkenes is most stable?
A.
B.
C.
D.
11. Addition of HBr to 2-butene is called ___________________.
A. Hydroboration hydration
C. Hydrohalogenation
B. Hydrogenation
D. Hydration
12. 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
13. Provide the reagents necessary to complete the following transformation.
OH
O
CO2
+
B. KMnO4 /H3O+
A. KOH /ethanol
C. CH2I2 /Zn(Cu)
D. non of these
14. bromination of an alkene occurs with:
A. anti stereochemistry
C. syn stereochemistry
B. cis stereochemistry
D. non Markovnikov addition
•
15. Addition of HBr to 2-butene is called ___________________.
A. Hydroboration hydration
C. Hydrohalogenation
B. Hydrogenation
D. Hydration
16. What is the major product of the following reaction?
OH
H2SO4 /heat
CH3
A.
D.
C.
B.
CH3
CH2
CH3
17. Which of the following reagents would be used to complete the following reaction?
CH3 – CH2 – CH2 – C ≡ C - H  CH3 – CH2 – CH2 – CH2 – CHO
A. 1. BH3,THF 2. H2O2, NaOH , H2O
C. KMnO4 / H3O+
B. HgSO4, H2SO4, H2O
D. none of these
18. How many allylic hydrogens does the following compound have?
CH - CH3
A. 3
B. 4
C. 6
D. 7
19. Oxidation of a terminal alkyne with either O3 or acidic KMnO4 will yield …..
A. one mole of a carboxylic acid
C. both A and B
B. one mole of carbon dioxide
D. two moles of carboxylic acids
20. What is the relationship between the following compounds?
OH
O
CH3 - C = CH - CH3
A. tautomers
D. identical
and
CH3 - C - CH2 - CH3
B. enantiomers
C. diastereomers
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:
CH3 - CH = C - CH2- CH = CH2
CH3
I
CH3
H
II
III
CH3
Br
C
C
H3C
C
H
C
CH3
C2H5
IV
I. _______________________________________
II. _______________________________________
III. ______________________________________
IV._________________________________________
b) Draw structures corresponding to the following systematic names;
(2Z)- 3-methyl-2-pentene
.
(2Z,4E)-3-bromo-4,5-dimethyl-2,5-heptadiene
2,3-dimethyl-1-cyclopentene
2.Mechanism
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
3. Synthesis:
Show by a series of reactions how could you prepare the following compounds from the
indicated starting compound. Be sure to clearly indicate the reagents used in each step.
a.
Cl
Cl
b.
CH3 - C
C-H
CH3 - C
C - CH2
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. Predict the major product
a) CH3 - CH2 - C
H2
C- CH3
Lindlar catalyst
b)
CH2 - C
HgSO4, H2 SO4
C-H
H2O
C
C- H
c)
1) NaNH2
2) CH3CH2Br
d)
e)
CH3 - CH2 - C
C
C - CH3
KMnO4/ H3O
C- H
2 HCl
Key:
Part I: Multiple choice
1-C; 2-C; 3-B; 4-B; 5-B; 6-C; 7-B; 8-B; 9-D; 10-A; 11-C; 12-B, 13-B,
14-A, 15-C, 16-B, 17-A, 18-D,
19-C, 20-A, 21-B, 22-B,
Part II: Show your work:
a) I. 3- Methyl-1-cyclohexene
II . (3Z) –2,4-Dimethyl-3-hexene
hexadiene IV. (2Z,4E)-3-bromo-4,5-dimethyl-2,5-heptadiene
III. 4- Methyl-1,4-
b)
(2Z)- 3-methyl-2-pentene
2,3-dimethyl-1-cyclopentene
(2Z,4E)-3-bromo-4,5-dimethyl-2,5-heptadiene
CH3
Br
C
H
CH3
CH3
C=C
C
CH3
CH3-CH2
C
H3C
C
CH3
C2H5
CH3
2.Mechanism
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
H
3.Synthesis
a.
Cl
Cl
CHCl3 /KOH
Cl2 /light
Cl
KOH /ethanol
( b) CH3 - C
C-H
CH3 - C
C -CH2
NaNH2
CH3 - C
C: Na
CH2Br
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. major products.
H
H
a)
b)
C=C
O
CH3
CH3-CH2
C
CH2 - C - CH3
O
C - CH2 - CH3
c)
d)
Cl
C - CH3
e)
Cl
CH3 - CH2 - C -OH + CH3-- COOH