Download Exam 2 - Wake Forest University

Exam 2
Chemistry 122
March 24, 2003
Do not open or begin this exam until instructed. This exam consists of 5 pages plus the cover
page. Before starting the exam, check to make sure that you have all of the pages. The exam has
a total of 100 points and includes 13 questions. Only legible answers written on the exam will be
considered for grading. All pertinent information needed for the exam is given. Notes and
textbooks are not permitted. This exam is administered under the Wake Forest Honor Code.
Name_______________________________________
1.
(4 points) Provide an IUPAC name for the following molecule. Include stereochemistry in
the name if necessary.
OH
2. (5 points) Provide a structure of (Z)-2-bromo-3-ethyl-4-methyl-2-pentene.
3. (3 points) Provide the structure of an amine. (Do not include multiple functional groups in
the molecule you draw.)
4. (3 points) Which of the following alkenes will release the most heat upon catalytic
hydrogenation?
1-hexene
2,3-dimethyl-1-butene
2,3-dimethyl-2-butene
5. (5 points) What would be formed as a result of the given electron-pushing arrows?
+
O
N
O
6. (2 points) Circle the strongest acid.
CH3OH
BrCH2OH
Br2CHOH
1
7. (4 points) Circle the strongest base in each set.
a.
CH3CH3
CH3OLi
CH3NHNa
b.
CH3CH2OH
CH3CH2ONa
O
CH3 C ONa
8. (15 points) For each of the following Bronsted-Lowry acid/base reactions
a. provide products that would form if the reaction proceeds as written
b. label the acid and base on each side of the reaction
c. draw an arrow indicating which way the equilibrium actually lies
CH3CH2C CLi
+
CH3CH3
(CH3CH2)2NCH3 +
H2SO4
O
O
+
F
OH
ONa
Cl
9. (6 points) The following alcohols may look similar on paper, but they behave quite
differently in acid/base reactions. One has a pKa of 10 and the other has a pKa of 16. Which
compound has which pKa? In the space provided explain your reasoning.
OH
OH
2
10. (12 points) For each pair, circle the reaction that proceeds the fastest by the given
mechanism.
a.
CH3OH
Br
OCH3
SN1
CH3OH
Br
OCH3
SN1
b.
CH3CH2Br
+
NaN3
CH3CH2N3 +
NaBr
SN2
O
CH3CH2OSCH3
O
+
NaN3
CH3CH2N3 +
SN2
O
NaOSCH3
O
c.
CH3CHBrCH3 +
NaNH2
CH3CHBrCH3 +
NaNH2
25 oC
E2
75 oC
E2
CH3CH=CH2 + NaBr + NH3
CH3CH=CH2 + NaBr + NH3
11. (21 points, 3 each) Provide the major organic products for each of the following reactions.
Include stereochemistry where necessary. If the predominant reaction pathway is an
elimination pathway, list all the alkenes that will be formed and indicate which one will be
formed in highest yield.
OTs +
NaOCH3
CH3OH
OH
+
HBr
3
Br
D
+
H2
Pt
25 oC
I
CH3CH2OH
(CH3)3COK
Cl
OH
(CH3)3COH
+
O
Cl
S
O
pyridine
Br
+
NaI
acetone
12. (5 points) Provide an acceptable structure for the missing starting material.
CH3I
+
CH3SCH2CH(CH3)2
4
13. (15 points) Provide an electron-pushing mechanism and a fully labeled reaction energy
diagram for the following reaction. (Include structures at every maximum and minimum
energy on the diagram.) You may assume the reaction is exothermic.
Br
+
NaCN
DMSO
CN
+
NaBr
5