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Practice Problems for Chapters 7 and 8. To be completed after completion of
the problems in the text.
1) Draw structures for the two products and explain how they are formed.
How might you enhance the yield of B?
Br
S
Br
S
C4H8S2
S
+
Br
+
S
C6H12S2Br2
A
S
S
B
2) Devise SN2 reactions that would give the following products starting with
your choice of alky halides.
CN
N3
O
NaN 3, DMSO
Br
N3
NaCN, DMSO
Cl
CN
NaH
OH
Br
O
3) Predict the major substitution product of the following reactions and
determine if they are formed from SN1 or SN2 pathways.
N
+
Br
+
I
N
SN2
Acetone
I
I-
HMPA
SN2
H2O
H3C
H3C
I
H
CH3
I
H
CH3
Br
H 3C
SN1
CNAcetonitrile H 3C
H 2O
EtOH
MeOH
SN1
OH CH 3
CN
CH 3
OH
or No Rxn
OMe
SN1
OEt
Br
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4) For the following dibromo alkane determine which position will react
faster (be more reactive) under SN1 and SN2 conditions. Explain your
answer.
Br
Br
3° fastest under SN1 because carbocation
1° fastes under SN2 because unhindered
5) Predict the major elimination product of the following reactions and
indicate if they are from E1 or E2 pathways.
Br
NaOH
E2
H2O
NaOMe
I
E2
MeOH
tBuOK
E2
I
DMSO
Cl
DBU
E2
3 eq. NaNH2
Br
Br
NH3
C
C
E2
6) Predict the major product in each of the following reactions and indicate
if it came from an SN1, SN2, E1, or E2 reaction.
H3C Br
NaOMe
H Br
CH3
E2
MeOH
H 2O
H 3C OH
CH 3
SN1
tBuOK
H Br
E2
DMSO
H3C Br
CH3
MeOH
H 2O
H I
EtOH
NaOMe
OH
SN1
CH 3
CH 3
E2
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7) For each of the following reactions, provide the appropriate reagents or products in the
boxes provided.
C
C
Br
+
Br
NaCN
Cl
CN
O
O Na
O
O
Br
O
+
NaBr
O
8) Answer the following questions for the reaction coordinate diagram shown below.
A. Give the letter(s) corresponding to the transition state(s). ___B,D____
B. Give the letter(s) corresponding to the reactive intermediate(s). __C___
B
C. Step 1 or Step 2 is the rate determining step. (circle one)
D. Step 1 is
endothermic
or
exothermic. (circle one)
D
Energy
C
E
E. Step 2 is
endothermic
F. The overall reaction is
or
exothermic. (circle one)
endothermic
or
exothermic. (circle one)
A