Prof. J. Sivaguru
Chem341 - Exam 3- [Blue]
Exam 3: CHEM 341 Organic Chemistry I
November 21, 2016 – 8.00 pm to 8.50 AM
Name:
_____“Practice Exam” - Key______
student id: _____________________
There are 8 questions and each carry 10 points. The 9th Question is a bonus
question.
Please answer any 4 of the 5 concept questions.
Question
Points – allotted
1 – Choose the best answer
5 questions x 2 points = 10
2 – Fill up
5 questions x 2 points = 10
3 – True / False
5 questions x 2 points = 10
4 – Concept question 1
10
5 – Concept question 2
10
6 – Concept question 3
10
7 – Concept question 4
10
8 – Concept question 4
10
9 – Bonus question
5
Total (70)
1/9
Points - earned
Prof. J. Sivaguru
Chem341 - Exam 3- [Blue]
1) Choose the best answer (10 points)
1-a) Which of the following is the correct IUPAC name of the product for the reaction
shown below?
CH 3C CCH2CH2CH(CH 3)2
Na, NH 3
A) cis-2-methyl-5-heptene
C) cis-6-methyl-2-heptene
B) trans-2-methyl-5-heptene
D) trans-6-methyl-2-heptene
Ans: D
1-b) How would you carry out the following conversion?
(CH 3)2CHC CH
(CH 3)2CHCH2CH2Br
A) (1) H 2/Lindlar Pd (2) HBr
B) (1) H 2/Lindlar Pd (2) HBr, peroxides
C) (1) HBr (1 eq) (2) H 2/Pd
D) (1) Br 2 (1 eq) (2) H 2/ Pd
A) A
B) B
C) C
D) D
Ans: B
1-c) Which of the following alkenes is expected to have the highest heat of
hydrogenation?
A) 1-pentene
Ans: A
B) trans-2-pentene
C) cis-2-pentene
D) 2-methyl-2-butene
1-d) How many stereoisomers are possible for the following diene?
H 3CHC CHCH2CH2CH CHCH2CH2CH 3
A) only 1
B) two
C) three
D) four
Ans: D
1-e) Which of the following alkenes exhibit E-Z isomerism?
I. 1-chloropropene
II. 2-chloropropene
III. 3-chloropropene
A) only I
Ans: A
B) I and II
C) II and III
2/9
D) I and III
Prof. J. Sivaguru
Chem341 - Exam 3- [Blue]
2) Fill up the needed answer in the questions below, Choose the best answer (10
points)
2-a) The HBr addition to
__Antimarkovnikov’s__ rule.
alkene
in
the
presence
of
peroxide
follows
2-b) The number of alkene isomers (including constitutional and stereoisomers) of C4H8
are____four___.
2-c) The geometry of following alkene is__Z___.
H
CH 3
C C
F
Cl
2-d) The hydroboration-oxidation reaction can be characterized as the
___antimarkovnikov__ addition to an alkene.
2-e) ___Water__ act as a nucleophile during acid catalyzed hydration of alkenes.
3) Answer True (T) or False (F) in the box provided for the statements below (10
points)
3-a) OH- is a good leaving group than H2O.
F
3-b) More stable alkenes have lower heats of hydrogenation.
3-c) cis-2-butene is more stable than trans-2-butene.
T
F
3-d) Primary alkyl halides undergo E2 elimination in the presence of a
strong base and polar aprotic solvent.
T
3-j) Hydrogenation of alkynes is usually performed in the presence of
Pt, Pd, Ni or Rh catalysts.
T
3/9
Prof. J. Sivaguru
Chem341 - Exam 3- [Blue]
4) Concept question 1 (10 points)
The following reaction undergoes dehydohalogenation via E1 mechanism. Write
the products of the following reaction. Also draw the mechanism along with arrow
pushings.
CH 3CH2OH
heat
Br
4/9
Prof. J. Sivaguru
Chem341 - Exam 3- [Blue]
5) Concept question 2 (10 points)
Complete the following sequence of reactions:
(a) H 3C C C H
1) NaNH 2
2) CH 3CH2CH2CH2Br
H2
Lindlar Pd
1)B 2H 6, diglyme
H 2, Pt
(b)
2) H 2O2, NaOH
Ans:
(a) H 3C C C H
1) NaNH 2
2) CH 3CH2CH2CH2Br H 3C C C CH2CH2CH2CH 3
2) H 2O2, NaOH
6. Concept question 3 (10 points)
Give the major product of following reactions:
Br 2
(a)
CH2
(b)
(c)
(d)
H 3C
CH2CH2CH2CH 3
HC CH
1)B 2H 6, diglyme
H 2, Pt
(b)
H2
Lindlar Pd
Br 2, H 2O
CH 3CO2OH
H 2C CH(CH2)5CH 3
1. O3, CH 3OH
2. (CH 3)2S
Ans:
5/9
OH
Prof. J. Sivaguru
Chem341 - Exam 3- [Blue]
Br
Br 2
(a)
Br
CH2
HO CH2Br
Br 2, H 2O
(b)
(c)
(d)
O
CH 3CO2OH
H 2C CH(CH2)5CH 3
1. O3, CH 3OH
2. (CH 3)2S
O
H CH
7) Concept question 4 (10 points)
Give the major product of following reactions:
(a)
CH 3(CH 2)7CHCH2Br 1. 3NaNH2, NH 3
2. H 2O
Br
+
(b)
2H2
Ni
OH
(c)
(d)
+
HC C(CH2)3CH 3
H2
Lindlar Pd
HBr
peroxides
Ans:
6/9
+
O
CH 3(CH 2)5CH
Prof. J. Sivaguru
(a)
Chem341 - Exam 3- [Blue]
CH 3(CH 2)7CHCH2Br 1. 3NaNH2, NH 3
2. H 2O
Br
+
(b)
2H2
Ni
OH
(c)
(d)
+
HC C(CH2)3CH 3
H2
CH 3(CH 2)7C CH
Lindlar Pd
OH
HBr
peroxides
BrCH CH(CH2)3CH 3
7/9
Prof. J. Sivaguru
Chem341 - Exam 3- [Blue]
8) Concept question 5 (10 points)
Complete the following reaction and draw the mechanism with arrow pushings:
H 3C
CH 3
C C
H
H
Br 2
H 2O
Ans:
Step 1
Step 2
H
H
C C
H 3C
CH 3
+
Br
H C C H
H 3C
CH 3
CH 3
Br
H C C H
H 3C
Br
Br
H C C H
H 3C
CH 3
Br
OH2
+
H 3C
CH 3
H C C H
Br
+
CH 3
Br
H C C H
O H
H 3C
H
OH2
H
OH2
CH 3
Br
H C C H
H 3C
O
H
OH2
Br
O H
CH 3
H C C H
H 3C
8/9
O H
+
Br
Prof. J. Sivaguru
Chem341 - Exam 3- [Blue]
9) Bonus question (5 points)
The following reaction is an example of Metal in liquid ammonia reduction of
alkynes. Draw the mechanism of following reaction.
H 3CH2C C C CH2CH 3
Na, NH 3
Ans:
Best of luck!
9/9
H 3CH2C
H
C C
H
CH2CH 3