Download jDonvert the following Fischer projections to dimensional formulas

1
King Fahd University of Petroleum & Minerals
Organic Chemistry I
CHEM 201
Term 101
Major Exam # 3
Tuesday, January 4th, 2011
90 Minutes
Dr. Mohammad Nahid Siddiqui
Section 1
Dr. Hasan Al-Muallem
Sections 2 & 3
Dr. Musa M. Musa
Section 4
Dr. Herman Perzanowski
Section 5
Name……………………….…. ID#……………
1
3
Questions
1-5
6-11
12-14
Total
Value
25
50
25
100
Score
Sec. #……….
2
H
Li
4
Be 5B
6
C
7
N
8
O
9
He
F 10Ne
11
Na 12Mg 13Al 14Si 15P 16S 17Cl 18Ar
35
Br
53
I
2
(2 points)
Q.1 Give the structure of the missing monomer(s)
H3C
C CH2
O
C
x
O CH3
POLY(METHYL METHACRYLATE)
(2 points)
Q.2 In the compound below arrange the hydrogens in order of increasing reactivity in a free radical
substitution reaction.
d H
H
eH H
H
H
H
H
c
H H
b
H
a
<
<
<
<
slowest
fastest
(6 points)
Q.3
Fill in the boxes with the correct main product(s).
(a)
(b)
CH2CH3
+
+
Br2
N-bromosuccinimide
light
CCl4
free radical
initiator
+
3
(9 points)
Q.4 Write equations for the initiation, propagation, and termination reactions
leading to the formation of bromocyclopentane from cyclopentane and bromine.
Br
+
Br2
light
Initiation reaction:
Propagation reaction:
Termination reaction (only one is required):
Which is the rate determining step?
+
HBr
4
(6 points)
Q.5
Bromine is less reactive but more selective than chlorine in free radical
halogenations as demonstrated by the following reactions:
Cl
Cl2
hv
CH3CHCH3 +
(55%)
CH3CH2CH2Cl
(45%)
CH3CH2CH3
Br
Br2
hv
CH3CHCH3 +
(98%)
CH3CH2CH2Br
(2%)
(a) Draw and show the difference in the energy diagrams of the rate
determining step for both Bromine and Chlorine. (Be sure to show the
relative energies of activation and whether the reactions are exothermic or
endothermic).
(b) Draw and show the difference in the transition states for Bromine and
Chlorine in the rate determining step of these reactions.
(c) Using these drawings explain how Bromine is more selective than
Chlorine in free radical halogenation
5
(26 points)
Q.6 Complete the following reactions by writing structures of missing compounds.
Show stereochemistry whenever applicable, and write NR if the reaction would not
give products.
CH3 OH
CHCH3
(a)
CH3
(b)
HCl
+
C
CH3CH2
ZnCl2
O
H
+ Cl
OH
pyridine
S
CH3
O
(TsCl)
O
CH3CO- Na+
(c)
H
(d)
H2CrO4 (excess)
HO
OH
CH3
CH3
CH3
H
OH
H
+
CH3
CH3
CH3
Br
H
6
(CH3CH2)3N
CH2OH
(e)
(f)
+
SOCl2
Na2Cr2O7
3-methyl-3-pentanol
H2SO4
O
(g)
1-butanol
+
O
O
(h)
OH
H
OTs
(i)
H3C
H
+
Na+ -CN
H
7
(j)
Cl + 2 Li
O
1) HCOCH2CH3
2)
CH3
(k)
H3O+
H2SO4
CH3CH2CH C CH3
OH CH3
(dehydration)
(4 points)
Q.7 Propose a detailed mechanism (use arrows and show all steps) for the following reaction:
CH3
CH3
OH
H
H2SO4
CH3
CH3
8
(3 points)
Q.8 List the following alcohols in order of decreasing rate of dehydration in the
presence of acid:
OH
CH2OH
OH
CH3
CH3
(a)
(b)
(c)
fastest
slowest
(3 points)
Q.9 Which of the following compounds could be successfully used to form a Grignard reagent?
Choose all applicable structures.
I
(a)
(d) CH3NCH2CH2CH2Br
O
(b) BrCH2CH2CH2COH
(c)
HOCH2CH2CH2Cl
(e) H2NCH2CH2CH2Br
(f)
Cl
CH3
Answer (write the compound letter(s)
(4 points)
Q.10 Propose a Grignard reaction to synthesize the following alcohol:
OH
9
(10 points)
Q.11 Propose a reaction (NO mechanism) to carry out each of the following conversions.
Note that more than one step is required for each reaction.
D
[4 points]
C
(i)
(R)-1-deuterio-1-propanol
(ii)
O
OH
C
OH
CH3CH2
[6 points]
D
H
CH3CH2
(only)
H
(S)-1-deuterio-1-propanol
CH2Br
10
(4 points)
Q.12 Draw the structures of the following compounds:
(a) 4-ethoxy-3-methyl-2-pentanol
(c) ethyl methyl sulfide
(12 points)
Q.13 Give major product of the following reactions:
O
O
(a)
+
CH3COH
O CH2CH3
+
+
NaH
(b)
H3C
(c)
HO CH2CH2CH2CH2 Cl
O
COOH
(d)
+
Cl
CH3
(e)
2 CH3C
[O]
SH
I2
H
O
(f)
CH2
CHCH2Cl
+
excess CH3S- Na+
excess HI
heat
11
(9 points)
Q.14 Give all reactants, intermediates and reagents for the conversion of A to B in the
following both reactions (No mechanism required).
(i)
OH
CH2
CHCH3
CH2
A
B
Cl
(ii)
CHCH2 CH2CHCH3
O
Cl
A
B
Good luck!