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AOC811S - ADVANCED ORGANIC CHEMISTRY -2ND OPP - JULY 2023 |
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n Am I BI A u n IVE Rs ITY
OF SCIEnCE
TECHnOLOGY
FACULTYOF HEALTH,NATURALRESOURCESAND APPLIEDSCIENCES
SCHOOLOF NATURALAND APPLIEDSCIENCES
DEPARTMENTOF BIOLOGY,CHEMISTRYAND PHYSICS
QUALIFICATION:BACHELOROF SCIENCEHONOURS
QUALIFICATIONCODE: 08BOSH
LEVEL: 8
COURSECODE: AOC811S
COURSENAME: ADVANCED ORGANIC CHEMISTRY
SESSION:JULY 2023
PAPER:THEORY
DURATION: 3 HOURS
TOTAL MARKS: 100
SECONDOPPORTUNITYEXAMINATION QUESTION PAPER
EXAMINER(S} DR. MARIUS MUTORWA
MODERATOR: DR. RENATE HANS
INSTRUCTIONS
1. Answer ALL the questions.
2. Write clearly and neatly.
3. Number the answers clearly
4. All written work must be done in blue or black ink and sketches can
be done in pencil
5. No books, notes and other additional aids are allowed
PERMISSIBLEMATERIALS
Non-programmable Calculators
ATTACHMENTS
pKa Chart and Periodic Table
THIS QUESTION PAPERCONSISTSOF 7 PAGES
{Including this front page and attachments)
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QUESTION 1:
Question type: Enolates and Carbon Nucleophiles
[22]
1.1} Analyse the factors that you expect to control stereochemistry of the following reactions
and draw the expected major products. Where applicable, clearly indicate the configuration of
the new stereo-chemical centre created.
a.
(1) 2 equiv LiNH:!NH 3
(2)
(2) CH31
0
II
b.
0 ~H
C :Ha 1) Li, NH3
(2)
II
CH3CO
2) CH31
1) NaOEt
C. CH3CH=CHC02CH3 + CH2(C0 2C2H5h --
(2)
2) -0H, W,
heat, -CO 2
3) Ac20,
heat
1) KHMDS
(2)
25°C
2) CH31
e.
(2)
f.
1) LiHMDS
(2)
1.2) Indicate reagents and approximate reaction conditions that could be used to effect the
following transformations. More than one step may be required.
(2)
b.
(2)
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00
C.
,Jl_ II
00
(2)
0_}-N{CCH2CH3
OCN~CH3
Ph' 'CH3
Ph____'"'CH3CH2CH=CH2
Ph3COCH2
d.
~o
Ph3COCH2
Yc~2CH= CH2
(2)
e. fi)qo~ a1q.~JJO
(2)
0
CH 3
CH3 CH3
QUESTION 2:
Question type: Functional Group lnterconversions
[28]
Show how you would prepare the following products from the given starting materials. Where
more than one step is required, show each step distinctly.
a.
(2)
(2)
C.
(4)
b d.
(8)
0
e.~
(4)
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f.
(6)
CHO
CHO
g.
(2)
QUESTION 3:
Question type: Protection/Deprotection of functional Groups
[10]
Using a protection group strategy, design a synthesis for the following multi-step transformation.
Show all the necessary reagents, reaction conditions and intermediates.
a. 0 0
0 Ph
{S)
,)l_jlOEt
~Ph
0
0
b.
(5)
HO~
HO~
Br
CN
QUESTION 4:
Question type: Mechanisms
Draw a full detailed mechanism for the enolate-based reaction below which results in the
formation of the coumarin ring.
CXCHO
O0
II
II
+ CH,..C, 'o,..C, 'CH
OH
3
3
~oAo
[16]
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QUESTION 5:
[24]
Question type: Pericyclic Reactions
Draw a detailed mechanism to explain how the following products are formed and indicate the
types of pericyclic reactions that are occurring in each step.
a.
Ph~~
-o
c;..--
/,
OH
Ph
'---o
o=wo (11)
+
H
b.
250°C
(13)
oAo~
THE END
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conjugate acid
sulfuric acid
H2S0 4
hydroiodic acid
HI
hydrobromic acid HBr
hydrochloric acid
..HCI:
H
/'J carbocations
+
protonated
alcohol
/'--• OHI.,+...H
hydronium ion
H,...0..·/'+H
H
nitric acid
HN0 3
hyckofluoric acid HF
:o:
carboxylic acids )lo ...H..
••
conjugate base
Hso;
I-
Br-
:c.1.:
..
/"-o,......H
.. H...•0.•.·.'.H
• N0 3
-
F
:o:
)lo:
pKa Chart
conjugate acid
conjugate base
-10
hydrogen cyanide H-C=N:
:c=N:
9.1
-9
phenols
v\\J,Hv~= ..
.. (cyanide)
-
10
-8
-7
\\Vater
. . H,.·.O.. .'H
- ..
:o• -•H
15.7
(hydroxide)
-3
.. primary alcohols /'-- .o.,...H
/'--a..: 16
(alkoxides)
-2.4
alkynes
c=c-H
c=c:
26
(acetylide anions)
-1.7
hydrogen
H-H
:H (hydride) 35
H
I
-1.3
U11111onia/amines
N
R,..."•' H
.
R,...N""'H
36
3.2
alkanes
..
(amide bases)
. ..........-......
~60
4.8
H
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h\\droge1
1
H
1.0079
llthlum
3
Li
6.941
sJdium
11
Na
~2.990
po:os;lum
19
K
~9.098
rubidium
37
Rb
1:5.468
caesium
55
Cs
13291
.francium
87
Fr
12231
berylllJm
4
Be
9.)122
magiesiurn
12
Mg
2L.305
c::icium
20
Ca
40.0i'B
strontiJm
38
Sr
87.62
barium
56
Ba
m.n
ra:lium
88
Ra
12261
57-70
*
89-102
**
scan::lium lililniJm vamdiJm
21
22
23
Sc Ti V
44.956
'.(ltrurr
39
y
47.e67
zlr:onlun
40
Zr
50.9'-2
nloblLm
41
Nb
88.906
lute:lun
71
91.224
hafnium
72
9,.906
tantalum
73
Lu Hf Ta
t74.9i
178.49 160.95
lawrencium rutherfordium dubnium
103 104 105
Lr Rf Db
12621
2611
12621
c1ranlum mangan€se Iron
24
25
26
Cr Mn Fe
51.995
54.93c
55.845
mclyt:denun techn~tlum rutheriun
42
43
44
Mo Tc Ru
9E.94
tJngsten
w74
1931
rherlun
75
Re
101.J7
oimlum
76
Os
183.84
seaborgum
106
'86.21
bohriun
107
190.23
hassium
108
Sg Bh Hs
12561
12641
12691
boron
car:JOn nllro;ier
5
6
7
BC N
10.811 12.)1'
aurninium silicor
14.C07
phosphoJrS
13
14
15
Al Si p
26.91:12 2B.)96
30.£74
cobalt
nicKe
copper
zinc
gollum gamanium ffS€1'1IC
27
28
29
30
31
32
33
Co Ni Cu Zn Ga Ge As
5e.923
rhc.diLm
45
58.693 63.546
p3l1;cdiLm sll~er
46
47
65.29
cadmlurr
48
69.723
Indium
49
72.61
tin
50
74.922
antlmon'(
51
Rh Pd Ag Cd In Sn Sb
1C2.S1
Iridium
77
106.42
platnu11
78
10787
god
79
112.41
mercury
80
114.82
th:clllum
81
118.7'
lead
82
121.76
bl5muth
83
Ir Pt Au Hg Tl Pb Bi
192.,2
195.08
19697
200.59 204.38
rneiherium ununnilium unununium Jnunl::ium
109 110 111 112
207.2
208.98
Jmnquadurr
114
Mt UunUuuUub Uuq
12681
12711
12721
12771
12891
o>ygen
8
0
15.999
sulfur
s16
32.065
sel9n1Jm
34
Se
78.96
tellurium
52
Te
127.60
polJnlum
84
Po
12091
fluorlre
9
F
18999
~hlorine
17
Cl
35453
xanlne
35
Br
79904
Iodine
53
I
123.9)
astatine
85
At
12101
1el1Jm
2
He
4.0021:
neon
10
Ne
20.18C
arg:m
18
Ar
'.\\9.941:
1:rypton
36
Kr
83.80
xeron
54
Xe
131.29
racbn
86
Rn
12221
*Lanthanide series
* * Actinide series
lanthanum
57
La
138.9'
:;ctlnlum
89
Ac
12271
cerium
58
Ce
14012
thoriJm
90
Th
~3204
prase,d~miurr neodymium promethlJm samarlun
59
60
61
62
Pr Nd Pm Sm
1LQ,91 144.24
prot~cli1lu11 Jronlum
u 91
92
Pa
11451
n€plLnlLm
93
Np
150.36
plutorlun
94
Pu
231.04 233.03
12371
12441
eurJplJm
63
Eu
151.96
americium
95
Am
124:l
gadollniJm
64
Gd
157 .25
curlun
96
Cm
12471
terburr
65
Tb
'59.93
berkelium
97
Bk
12471
dyspnJ5\\Ull holmium
66
67
Dy Ho
162.50 1E4.£3
cali'ornlum elnslelnlum
98
99
Cf Es
12511
12521
9rtlum
68
Er
167.26
fermium
100
Fm
12571
thulium ytterburr
69
70
Tm Yb
16893
1~3.04
merdeleviJrr nooetiurr
101
102
Md No
12581
12591
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