Chem 201
Van Vranken
Practice Problem Set
We have pulled some problems from an undergraduate textbook to make sure you can push arrows
using basic rules from Chem 201. These problems are relatively easy compared to typical problems we will
confront on our problem sets. If you experience difficulty with the mechanisms below then make sure to
review that material using an undergraduate textbook familiar to you.
1. All arrow-pushing must begin with correct Lewis structures. Draw valid Lewis structures for each of the
following compounds. Include all non-bonding lone pairs.
a. acetic acid (CH3CO2H)
e. t-butyl isonitrile (CH3)3CNC
b. acetaldehyde (CH3CHO)
f. methyl formate (CH3O2CH)
c. acrolein (H2C=CHCHO)
g. benzoyl fluoride (PhCOF)
d. hydrogen peroxide (H2O2) h. methyl isocyanate (CH3NCO)
Suggest arrow pushing mechanisms for the following reactions
2. SN1 and SN2 reactions1
excess
HBr
Br
100 °C
O
Br
2. Alkene addition reactions2
OMe
OH
NaO 2C
OMe
I2
OH
NaHCO 3
5 °C, 12 h
O
O
80%
I
4. Electrophilic aromatic substitution3
O
+
Cl
Cl3C
4 equiv.
CCl3
H 2SO 4
95%
neat
15 °C, 5 h
Cl
5. Enamine formation4
Ph NH
+
O
cat. AcOH
toluene
-H2O
110 °C
Ph
N
Cl
Chem 201
6. Enolates
Van Vranken
5
You were probably mis-lead into believing that this is how you carry out Robinson annulations.6
O
O
O
O
NaOMe
O
O
MeOH
25 °C, 9 h
ONa
no
O
>80%
7. Conjugate addition 7
OAc
NO 2
NMe 2
Me 2NH
NO 2
64%