CHEMISTRY 222: Spring 2001
Review Problems
Page 1
There are 14 Questions on 14 pages. Make sure you have them all.
Question 1
Provide an unambiguous name for the following compounds. Be
sure to use cis/trans, E/Z or R/S where appropriate.
Br
a)
2,2-dibromo-3-hexyne
Br
CO2H
Cl
2,3,5-trichlorobenzoic acid
b)
Cl
Cl
Cl
c)
Cl
Cl
trans-1,1,2,4-tetrachloro-1,3-butadiene
Cl
d)
naphthalene
CH3
I
e)
4-bromo-3-fluoro-2-iodotoluene
F
Br
f)
Br
g)
Cl
CH2 CH2 C
CH
Cl
4-bromo-1-butyne
para-dichlorobenzene
CHEMISTRY 222: Spring 2001
Page 2
Review Problems
2) Draw the major resonance structures of the following cations
a) CH2 CH
CH
+
CH2
CH
+
+
+
+ CH2
b)
CH2 CH
C
CH2
+
+
3) For each of the following resonance structures, circle the one which contributes more
to the resonance hybrid
a)
b)
c)
+
CH2 CH
CF3
CH
–
CH CH
CH2 CH
CH3
CH
OCH3
CH3
CH2 CH
+
CH
CF3 CH CH
–
CH2 CH
+
OCH3
CH3
–
CH
CH3
CHEMISTRY 222: Spring 2001
Question 3
Page 3
Review Problems
Rank the following in order of:
a) Increasing energy
•
A
B
D
–––
b)
<
A
–––
C
< –––
D
B
< –––
Increasing exothermicity of hydrogenation
B
A
A
–––
c)
C
C
<
B
–––
C
< –––
D
D
< –––
Increasing rate of reaction in a Diels-Alder reaction
O
(CH3)2N
O
O
CH3O
CH3
A
B
C
–––
d)
<
C
B
–––
D
D
< –––
A
< –––
Increasing bond dissociation energy of the C-H bond
H
H
H
H
A
B
B
–––
C
<
C
–––
A
< –––
D
D
< –––
CHEMISTRY 222: Spring 2001
Page 4
Review Problems
Question 4
For each reaction, give the major organic product. Pay attention to stereochemistry
OH
O
1. CH3CH2MgBr
a)
2. H3O+
CO2CH3
CO2CH3
heat
b)
CO2CH3
CO2CH3
O
CN
O
heat
CN
c)
CN
CN
Br
CN
NaCN
d)
Br
HBr
e)
H3CO
OCH3
Na / NH3 (l)
f)
CH3CH2OH
H3CO
OCH3
CHEMISTRY 222: Spring 2001
Page 5
Review Problems
Question 5
For each reaction, give the major organic product. Pay attention to stereochemistry
CO2CH3
CO2CH3
heat
a)
CO2CH3
CO2CH3
O
Zn(Hg)
b)
HCl, H2O
N(CH3)2
N(CH3)2
CN
heat
c)
CN
NaOEt
Br
d)
O
EtOH
Br
Br2, hν
e)
CN
CN
heat
f)
NC
H
H
CN
CHEMISTRY 222:Spring 2001
Page 6
Review Problems
Question 6 Which of the following structures are
a) cumulated?
A
E
b) conjugated?
C D F H
c) isolated (non-conjugated)?
B G
H
C
C
O
O
H
A
C
B
CH3
H2C
C
CH3
CH2
+
CH3
CH3
E
D
F
G
H
CHEMISTRY 222: Spring 2001
Question 7
Page 7
Review Problems
When in a flat configuration, which of the following compounds are:
a)
Aromatic?
C E F G H
b)
Non-aromatic? B J
c)
Antiaromatic?
A D
–
–
A
C
B
N
D
E
+ +
F
O
O
G
H
J
CHEMISTRY 222: Spring 2001
Page 8
Review Problems
Question 8 Give the reagents/conditions to perform the following transformations. Some will require more
than 1 reagent, in which case use the 1. ... and 2. ... notation on the arrow.
1. boil KMnO 4
a)
CO2H
2. H3O+
OH
1. BH3 . THF
b)
2. –OH, H2O2
Br
Ph
PhMgBr
c)
H2 100 p.s.i.
d)
Pd/C
CN
O
O
CN
NC
d)
heat
H H
CN
CHEMISTRY 222: Spring 2001
Page 9
Review Problems
Question 9 Show how you would make compounds B from compounds A. More
than one reaction is required. Show the reagents and any intermediate
compounds. It is not necessary to show any mechanisms.
HO
A
B
O
1.
Br2, hν
2. H3O+
Br
BrMg
Mg . THF
OH
HC
CH
CH3 C
1. NaNH2
1. NaNH2
2. CH3Br
2.
CH3 C
CH
O
3. H2O
C
CH2 CH CH3
CHEMISTRY 222, Spring 2001
Review Problems
Page 10
Question 10
Which reaction, A or B, would you expect to be faster, and why?
A
H
H
H
H
B
Reaction B would proceed via a Möbius transition state which is thermally allowed for
a 4 electron electrocyclization reaction. Reaction A would proceed via a Hückel
transition state, which is thermally forbidden for this reaction.
This isomerization reaction can be induced thermally. It goes via an intermediate compound X.
Draw the structure of X. Do the reactions proceed via a Hückel or a Möbius transition states?
CH3
Ph
Ph
Ph
heat
CH3
heat
X
Ph
Ph
CD3
Ph
CD3
Ph
CH3
Ph
X =
Ph
Ph
CD3Ph
Ph
both proceed via Möbius
transition states
CHEMISTRY 222, Fall 1999
Review Problems
Page 11
Question 11
Give the diene and dienophile which react to give the Diels-Alder products shown
NC
CN
CN
CN CN
NC
CN
CN
CN
CN
CN
CN
CN
CN
CN
Cl
O
H H
Cl
CN
This transformation goes via pericyclic reaction A to give compound X, which reacts via
pericyclic reaction B to give the final products shown. Draw X. Do the reactions proceed via
Hückel or Möbius transition states?
CO2CH3
O
O
CO2CH3
A
+
X
B
+
CO2CH3
CO2CH3
O
O
X =
CO2CH3
CO2CH3
both involve 6 π electrons
and both proceed via
Hückel transition states
CO2
CHEMISTRY 222: Spring 2001
Page 12
Review Problems
Question 12
Provide detailed (arrow pushing) mechanisms for the following transformations
a)
H2SO4
H
SO4H
H
+
+
H
d)
H
–
O SO3H
H
Provide detailed (arrow pushing) mechanisms for the following transformation.
Indicate which would be the major product.
OCH3
Br
OCH3
CH3OH
+
heat
..O
Minor
CH3
CH3
..O
H
+
H
+
CH3
..O
CH3
H
+
O
H
..
O
CH3
H
CH3
H
O+
Major
CHEMISTRY 222: Spring 2001
Page 13
Review Problems
Question 13. Draw in the box the structure of the compound which
has the IR, 13C and proton NMR spectra given below. The
molecular formula is C9H12. If you can't get the whole structure
put as many fragments as you can figure out.
3H
140
120
100
60
80
40
5H
1H
CHEMISTRY 222: Spring 2001
Page 14
Review Problems
O
CH3
H
Question 14. Draw in the box the structure of the
compound which has the IR, 13C and proton NMR
spectra given below. The molecular formula is
C8H8O. If you can't get the whole structure
put as many fragments as you can figure out.
this peak is actually
2 very closely
spaced peaks
1H
3H
4H