Name: ________________________
CHM 427
Organic Chemistry II
Final Exam
April 23 2008
You may start as soon as You sit.
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1
1. Fill the blanks as required. (2 marks each)
a.
?
OH
O
b.
H+ / H2O
CrO3
?
?
c.
O
?
?
?
O
OH
d.
O
POCl3
?
?
H
H
OH
O
e.
Br2, MeOH
?
Ph
?
PPh3
Ph
f.
O
N
?
g.
KMnO4
SOCl2
?
?
NH3
N
?
?
h.
Br
?
OMe
OH
2
i.
O
OH
CrO3
H+/MeOH
?
?
Br
j.
EtO
O
2.0 eq methylmagnesium bromide
?
Cl
k.
O
LiALH4
N
?
2. Consider the conversion of 2-Methylpentanoyl chloride (an acid chloride) to Cyclohexyl 2-Methylpentanoate
(an ester). Draw the complete mechanism showing how cyclohexanol reacts with the acid chloride in the presence
of pyridine to make the ester. (5 marks)
3. The pKa of phenol is 9.89 while that of p-nitrophenol is 7.15. Explain the difference in acidity using resonances
forms. (5 marks)
3
4. Show using Newman Projections why the E2 mechanism leads predominantly to (E)-3-methyl-2-pentene while
the E1 mechanism leads to a mixture of E and Z isomers. (10 marks)
?
E2
Br
H
H
CH 3
E1
?
5. In organic we speak of basicity and nucleophilicity. What is the difference? (5 marks)
4
6. Consider the following data for some alkyl halides’ R-X bond:
1. Bond length (pm):
178, 214, 193
2. Bond strength (kJ/mol): 293, 351, 234
These values belong to methyl iodide, methyl bromide and methyl chloride. Match up the lengths and strengths to
the corresponding compound. (5 marks)
7. Consider the reaction of a lithium amide and a terminal alkyne:
N
Li
+
H
N
+
Li
H
Which direction will the reaction proceed if the amine has a pKa of 35.4 and the alkyne has a pKa of 28.3. Explain
why. (5 marks)
5
8. The formula of the compound that gives the following spectra is C3H6O. Suggest a possible structure(s) and be
sure to assign all three spectra as you would in your labs. Yes, there are two peaks in the carbon at 48.22 and 48.01
and one of them is half the size of the other. (10 marks)
COPYRIGHT 1998
200
150
100
50
0.00
18.04
77.61
77.19
76.77
ALL RIGHTS RESERVED
48.22
48.01
Sigma-Aldrich Co.
0
COPYRIGHT 1998
Sigma-Aldrich Co.
1.33
1.31
ALL RIGHTS RESERVED
0.13 0.14 0.14
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
0.39
2.0
1.5
1.0
0.5
0.0
6
9. The formula of the compound that gives the following spectra is C9H9ClO2. Suggest a possible structure(s) and
be sure to assign all three spectra as you would in your labs. (20 marks)
COPYRIGHT 1998
11
10
9
0.20 0.31
8
7
6
5
4
0.00
0.20 0.20
3
2
1
0
COPYRIGHT 1998
200
150
100
50
0.00
55.24
52.23
77.46
77.04
76.62
114.31
123.24
159.41
ALL RIGHTS RESERVED
130.63
Sigma-Aldrich Co.
172.18
12
4.05
3.78
ALL RIGHTS RESERVED
7.18
7.15
6.89
6.86
Sigma-Aldrich Co.
0
7
8
10. Show how you would carry out the following transformations. More than one step may be required. Do
THREE of the following four. (5 marks each)
a.
OH
b.
I
NH2
c.
O
Cl
d.
Ph
H
N
9
11. Show how you would carry out the following transformations. More than one step may be required. Do
TWO of the following four. (10 marks each)
a.
O
OEt
Ph
OMe
b.
O
O
c.
O
O
d.
10