1
King Fahd University of Petroleum & Minerals
Organic Chemistry
CHEM 201
Term 091
Major Exam # 2
Wednesday December 30th, 2009
Two hours
Dr. Mohammad Nahid Siddiqui
Dr. Musa M. Musa
Dr. Hasan Al-Muallem
Dr. Amer El-Batta
Name……………………….….
Questions
Value
Section 1
Section 2
Sections 3 & 4
Section 5
ID#……………
Score
1
1-8
Sec. #……….
46
3
2
H
Li
4
Be 5B
6
C
7
N
8
O
9
He
F 10Ne
9 - 14
22
15 - 23
32
35
Total
100
53
11
Na 12Mg 13Al 14Si 15P 16S 17Cl 18Ar
Br
I
2
(20 points)
Q1. ● Predict the major product(s) of the following reactions. If no reaction occurs, write NR in the
product side.
 Indicate the stereochemistry of the product(s) when it is applicable.
 Specify within the box the type of the reaction pathway (SN1, SN2, E1 or E2) by which each
major product is formed.
3
G)
Br
D
H
O-K+
4
(3 points)
Q2. Rank the following alkyl halides in order of increasing rate of the SN1 reaction. Do not redraw
the structures inside the table, and write only the letters which correspond to each alkyl halide.
Least Reactive
Most Reactive
(5 points)
Q3. Propose a mechanism for the following reaction showing structures of all possible intermediates.
Use curved arrows to indicate the electron flow.
5
(3 points)
Q4. Using chair conformations, explain the result of the following E2 reaction:
(5 points)
Q5. An alkyl bromide reacts with a nucleophile as shown in the equation below. The reaction rate
data were reported in the table:
Experiment #
1
2
3
[R-Br]
[Nu-]
0.01
0.03
0.02
0.01
0.01
0.03
relative rate
1
3
2
Indicate which of the following statements is/are True or False with respect to the above
reaction:
________ (A) A concerted back-side attack reaction
________ (B) An ionization reaction
________ (C) A first order reaction
________ (D) Proceeds with racemization
________ (E) Proceeds with inversion of configuration
6
(3 points) Q6. To prepare isopropyl methyl ether, which of the following two reactions (A or B) would
give a higher yield? Explain your choice.
(3 points) Q7. When cis-4-bromocyclohexanol undergoes E2 reaction, two products (A and B) with
C6H10O formula are produced. Draw the structures of the two products inside the boxes,
and indicate what their relationship is to each other?
(4 points) Q8. In the following substitution reaction, two products were formed as shown.
(A)
Circle the major product. (1 POINT)
(B)
Justify your answer by drawing the structure of the intermediates. (3 POINTS)
7
(4 points)
Q.9 Rank the relative stabilities of the alkyl radicals in the following compounds:
CH2
B
A
C
Least stable
D
Most stable
(3 Points)
.
Q.10 Which of the following properties is/are the same in alkyl radical (R3C ) and carbocation (R3C+)?
a) Hybridization
--------------------------------
b) Geometry
--------------------------------
c) Rearrangement
--------------------------------
(4 Points)
Q.11 Give the major product from each of the following reactions:
O
O
N
initiator, hv
(a).
O
NBS
NBS
CH3
CH2CHCH3
(b).
initiator, hv
NBS
Br
8
(7 points) Q.12
In each of the following, which reaction is faster? Write A or B in the box.
A
CH3
CH3 C
CH3
CH3
(a).
CH3 C H
CH3
CH3
B
CH3 C
CH3
A
Cl2/hv
CH3
CH3 C Cl
CH3
CH3
(b).
CH3 C H
CH3
CH3
B
Br2/hv
CH3 C
Br
CH3
(c). Use the following Energy diagram for the Cl2/hv and Br2/hv reactions with an alkane,
and fill up either A or B in the given table.
Exothermic
More Selective
Transition state is
H CH3
H C

X
CH3

Transition state is X
H
H CH3
C
CH3
Energy diagram for bromination
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(2 Points)
Q.13 Draw a chemical structure for the following:
(a). Free radical initiator
(b). Free radical inhibitor
(2 Points)
Q.14 Identify type of the following of polymer structure (Atactic or Syndiotactic or Isotactic) and
write its monomer.
CH3 CH3
CH3 CH3
CH3 CH3
Monomer
Type of polymer
(4.5 points)
Q.15 Give the IUPAC name for the following alcohols:
CH3
CH3
OH
(a)
H
OH
(b)
H3C
Br
H
OH
(c)
CH3
OH
10
(2.5 points)
Q.16 Rank the following compounds in decreasing order of acidity.
Please don’t redraw the structure write only the letter corresponding to the compound.
CH3
OH
Cl CH2CH2 OH
CH3 C OH
NH3
CH3
A
B
C
D
Strongest acid
E
Weakest acid
(3 points)
Q.17 Draw structure of the missing organic compounds in the following reaction:
1)
2 Li
Cl
OH
+
2) H2O, H
(4 points)
Q.18 Give a Grignard reaction that could lead to synthesis of the following alcohol.
OH
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(4 points) Q.19 Write a sequence of reactions to show how you would carry out the following conversion
using tosyl chloride as one of the reactants (and whatever needed chemicals/reagents).
(Mechanism is not required)
O
to
CH3CH2OH
CH3CH2O
ClS
CH3
O
tosyl chloride
(4 points) Q.20 Propose a mechanism showing all steps for the following conversion.
Use arrows to indicate the flow of electrons.
H
HBr
Br
C OH
CH3
CH2CH3
(3 points) Q.21 Predict the major organic product of the acid-catalyzed dehydration of the following alcohol.
H2SO4
OH
100oC
12
(3 points)
Q.22 Starting with trans-4-methylcyclohexanol, give (in the box) the reagent necessary to achieve
each of the following conversions:
CH3
Cl
H
H
CH 3
H
CH3
+
H
H
Cl
H
OH
trans-4-methylcyclohexanol
CH3
Cl
H
H
only
(4 points)
Q.23 Show how you would accomplish the following conversion (more than one step is needed).
Assume availability of whatever oxidizing agent, Grignard reagent and any other reagent you
may needed.
OH
CH2OH
CHCH2CH3
to