CH 243 ORGANIC CHEMISTRY 1 (FALL 2008)

CH 243 ORGANIC CHEMISTRY 1 (FALL 2008)

CH 243 ORGANIC CHEMISTRY 1 (FALL 2008) - EXAMINATION 3
(November 20, 2008)
Recitation Section:
(Please print)
Pledge: I pledge my Honor that I have abided by the Stevens Honor System.
Answer the following questions. Please indicate the letter/ number choice of your answer clearly.
Each multiple choice problem is worth 4 points.
1. Predict the major product of the following reaction.
H:SO,
heat
CH,
cW,
A) CH;CH:C=CH
B) CH;CH=CCHCH,CH;
CH;CH=C(CH3)2
B) (CHtfeCHCH-CH?
2. How many isomeric alkenes are possible, including stereoisomers, in the following reaction?
Br
NaOCHjCH,
C. four
A. two
D. five
3. hi the dehydrohalogenation of 2-bromobutane, which conformation below leads directly to the formation oi
fr-a/w-2-butene?
CH3
CH3
Br
H
H
a
B. only II
A. only I
D. I and II
4. What is the major product of the following reaction?
HBr
A)
Br
u
5. Addition of HCI to 3-methyl-l-pentene gives two products. One of these is 2-chloro-3-methylpentane. What
is the other product?
A. l-chloro-3-methylpentane
B. 3-chloro-3-methylpentanev
1). 2-chloro-2-methylpentane
6. Addition of hypobromous acid, HOBr, to 1-methylcyclohexene gives:
CH3
CH3
Ur
B)
A)
o
C)
OH
OH
7. Select the best reaction sequence to make the following ketone.
O
II
^1) propyne, NaNH2 (2) 1-bromobutane (3) H2O, Hg , H2SO4
. (1) acetylene, NaNH2 (2) 1-bromopentane (3) H2O. Hg2+, H2SO4
<^7XT)~t-lieA3>iie,"NaMlt2~t2)'bion't»aretiiaiiie (3) H2O, He* , H2SO4
D. (1) 1-pentyne, NaNH2 (2) bromoethane (3) H2O, Hg , H2SO4
8. Which of the followi
es cannot be made by the acid-catalyzed hydration of an alkyne?
o
o
o
D)
A)
9. Which of the following is the correct IUPAC name of the product for the reaction shown below?
Na NH3
'
CH3C=CCH2CH2CH(CH3)
A. £&-2-methyl-5-heptejie
&. cw-6-methyl-2-heptene
- 04-CW^CV^ CH CC U$\
B. /ra/j5-2-methyl-5-heptene
&. /r<ms-6-methyl-2-heptene
10. Identify the allylic halide(s).
Br
Br
zCl
CH2
Cl
ii
A. only II
m
B. I and II
C. I and IV
D. I, III, and IV
[ 1. In each of the following pairs of compounds, indicate which reacts faster: (2 points each)
B ,
(i) On being treated with sodium ethoxide in ethanol:
(a) 2-bromo-3,3-dimethylpentane
(b) 2-bromo-2,3-dimethylpentane
(ii) On being treated with cone, sulruric acid at 120°C;
(a) 1,2-dimethylcyclopentanol
(b) 3,4-dimethylcyclopentanol
(iii) In a reaction with bromine (Br2);
(a) 1,2-dimethylcyclopentene
(b) 1,5-dimethylcyclopentene
(iv) In a reaction with HC1;
(a) 2-methyl-2-pentene
(b) trans-3-hexene
cc^ccc
(v) On being treated with KOC(CH3)3 in (CH3)3COH at 70°C;
ftH
• CHyijC
(b)
(a)
(vi) In an E2 elimination reaction;
H,C
lljC
CIljBr
fir
.ah
(b)
(a)
(vii) When treated with NaNH2 in NH3 followed by reaction with bromoethane;
(a) 1-butyne
(b) 2-butyne
.A.-'
(viii) In a palladium catalyzed hydrogenation reaction:
(a) cw-3,4-dimethylcyclohexene
(b) /ra«s-3,4-dimethylcyclohexene
(ix) In the halogenation reaction of frwis-2-butene
(a) C12
(b) Br2
(x) In an E2 elimination reaction:
(a) 2-methyl-2-propanol
j
(b) 2-bromo-2-methylpropane
CA,
C-C.-C
c-c-c
'
12. Suggest a sequence ot reactions suitable for carrying out the following conversions. You may use any
organic/ inorganic reagent (as appropriate). If any step of the reaction yields two (or more) products, indicate
the major product (the one that you will use for the next step). Draw the structures of all reactants and
products (indicating stereochemistry, where appropriate).
5 points each
(a) Convert 2-propanol into propyl cyanide (butanenitrile, CH3CH2CH2CN)
ov*
(b) Convert ethene to 1-butyne
CH^CM!
13. Indicate the structure of the major organic product in each of the following reactions. Indicate product
stereochemistry (as and where appropriate). If you have reason to believe a product cannot be obtained under
the conditions described, simply state "NO REACTION".
3 points each
H3C
'-
CH3
KOCH3
DMSO, 70°C*
C^
EtOH,
(CH3)3C
H
V
heat
H
- cfj
H
Hyp,
CH3
B2D6/diglyme
H2O2,NaOH*
CH2CH3
I. JUNH 2 /NH 3
4.CH,I
a±i
BrVH^O
OH
(l)
CH3CH2CH2C=CH H20/HVHgS04
»•
BH/THF
H2O2, NaOH
'cJW*
0
OW
Bonus Problem: (10 points for perfect answer, no partial credit)
Starting with propane, indicate how you would prepare either of the following compounds (a) Z-2-hexene and
(b) E-2-hexene. You may choose any organic / inorganic reagents and solvents you deem appropriate for the
reaction. (Please show the scheme for the synthesis of one compound only)