CHE 232 - Organic Chemistry
Exam 2, March 9, 2004
Name
KEY
Student ID No.
Before you begin this exam: First: You are allowed to have a simple model set at your seat.
Please put away all other materials. Second: Place your student identification on your desk. A
proctor will come around to check everyone’s ID. If you do not have ID, tell the proctor. Third:
Read through the entire exam. Your goal, as always, is to score as many points as possible. Do
not waste time on problems that you can’t do if there are others that look easy. Fourth: It is
critically important that your answers be written in a clear, unambiguous manner. Answers in
which your intentions are unclear will not receive credit. Fifth: READ THE
INSTRUCTIONS FOR EACH PROBLEM. Answer the question that is asked.
If you wish to have your exam score posted beside your student ID number in the glass case (1st
floor, CP Building, behind CP-139) with the exam key, place an ‘X’ in this space
.
If you do not mark this space, your exam score will not be posted.
You have 75 minutes to complete this exam. There will be no extensions, so budget your time
carefully.
Problem
Points
1.
20
2.
30
3.
10
4.
10
5.
10
6.
20
Total
100
Score
1
1.
(20 points) Multiple choice. Choose the one best answer for each of the following.
i) Which of the following methods is the best way to accomplish the transformation
shown?
O
OH
CH3
(a)
(b)
(c)
(d)
CH
CH3 3
+
(1) CrO3; (2) LiAlH4; (3) D3O
NaBH4
(1) CH3MgBr; (2) H2O, HCl
+
(1) LiAlH4; (2) H3O
ii) Which of the following methods is the best way to accomplish the transformation
shown?
H
OH
D
OH
+
(a) (1) CrO3; (2) LiAlH4; (3) D3O
(b) (1) CrO3; (2) LiAlD4; (3) H3O
+
+
(c) (1) LiAlD4; (2) H3O
+
(d) (1) LiAlH4; (2) D3O
iii) Which of the following methods is the best way to accomplish the transformation
shown?
OH
(a)
(b)
(c)
(d)
D
(1) PBr3; (2) Mg; (3) D3O+
+
D3O
D2, Pt
(1) Mg; (2) D3O+
2
iv) Which of the following methods is the best way to accomplish the transformation
shown?
Br
OH
O
(a) (1)
; (2) H3O+
(b) (1) CH3CHO; (2) H3O+
(c) (1) Mg; (2) CH3CHO; (3) H3O+
(d) (1) Mg; (2)
2.
O
; (3) H3O+
(30 points) Predict the product of the following reactions. If you believe that no reaction
will occur, write ‘no reaction.’ DO ANY 6 OF THE 12 GIVEN.
a)
O
OH
HO
O
O
catalytic TsOH
b)
1. LiAlH4
2. dilute Aq. HCl
O
OH
c)
PBr3
OH
Br
d)
O
O
O
1. NaOEt
OEt
O
OEt
2.
Br
e)
OH
O
OH
O
OH
xs K2Cr2O7
H2SO4
3
f)
O
OH
1. CH3CH2MgBr
2. H2O, HCl
g)
O
O
1. LDA
2.
CH3O
CH3O
Br
h)
1. Ph3P
Br
2. BuLi
O
3.
i)
H
1. LiAlD4
H
OH
O
2. H2O, HCl
H
D
H
Note: a) D is deuterium; b) show the resulting stereochemistry
j)
O
OH
H
catalytic TsOH
HO
O
(1 equiv.)
k)
O
1. CH3Li
OH
2. H2O, HCl
4
l)
O
1. LDA
2.
O
O
H
3. HCl, H2O
3.
(10 points) Show how 1-butanol can be converted to the various products shown.
More than one step may be required. If so, indicate 1) reagent 1; 2) reagent 2, etc.
DO ANY TWO OF THE FOUR.
a)
OH
PCC or CrO3/pyr
O
H
b)
OH
CrO3/H2SO4 or KMnO4
O
or K2Cr2O7/H2SO4
OH
c)
OH
1. PBr3 or TsCl/pyr
CN
2. NaCN
d)
OH
1. PBr3
D
2. Mg
3. D2O
5
4.
(10 points) Show how n-hexane can be prepared from units of 3 carbons or less.
(CH3CH2CH2)2CuLi
Br
or
O
Br
Mg
OH
1.
MgBr
H
2. H2O, HCl
PBr3
1. Mg
Br
2. H2O
5.
(10 points) Provide a viable mechanism for the following reaction. Pay attention to the
use of mechanism arrows, and watch every proton transfer step! NOTE: DO NOT ADD
ANY ADDITIONAL REAGENTS!
NH2
N
O
H2N NH2
Catalytic HCl
H
H N NH2
H
O
H2N NH2
H
O
NH2
N
H2N NH2
HO
H
NH2
N H
H2N NH2
NH2
H N
H
H N NH2
H
H
NH2
N
HO
H
O
H
H
NH2
N
6
6.
(20 points) Provide viable syntheses for the compounds below, using only benzene,
inorganic reagents, triphenylphosphine, LDA, and organic reagents of 3 carbons or less.
DO ANY 2 OF THE 4 BELOW.
a)
O
OH
H
MgBr
Br
O
Br
Br2, FeBr3
MgBr
Mg
1.
OH
H
2. H2O, HCl
b)
O
O
O
H
O
Cl
O
Cl
AlCl3
O
O
O
H
KOH, heat
7
c)
OH
MgBr
Br
O
O
O
CH3I
O
1. LDA
2. CH3I
2. H2O, HCl
MgBr
Mg
Br
OH
1. mix
d)
PPh3
O
O
H
O
H
Br
MgBr
O
H
O
1. H
1. Br2
2. FeBr3
3. Mg
PBr3
MgBr 2. H2O, HCl
O
O
H
KOH, heat
O
OH
Br
1. BuLi
PPh3
H
mix
END OF EXAM
8