Unformatted text preview: CHM 201- Organic Chemistry I
Answers on last page. Exam 2 Key Questions 1-8. For each pair of structures shown, indicate their relationship from the answer
choices below. Answers can be used more than once.
(d) constitutional isomers
different compounds that are not
(e) identical compounds 1. 2. HO OH P
H CH2 C l
F F CH 2 Cl
OH H OH 3. 4. C H3 H F 5. H 6. H C H3 H F OH 7. OH OH C H3 H H C H3 C H3 H H C H3 OH NH 2 8. OH OH HO N H2 9. D iscodermolide, shown below , has how many chiral carbons? HO
O O OH O
NH 2 OH O OH a. 9 or less b. 10 c. 11 d. 12 e. 13 or more 10. Assign R/S configurations to carbons A and B, respectively in the compound shown below.
For your convenience, the molecule is shown twice so you can do your assignments separately.
a. R, R
b. R, S
c. S, R
d. S, S C H 2C H3 A
H B H OH HO OH HO H
CH3 C H2 C H3 A B H
C H3 1 11. The observed specific rotation of a mixtur e (of unknown proportions) of a pair of pure
enantiomers was determined to be -10°. If the known specific rotation of the pure dex trorotatory
enantiomer is +50°, what is the relative composition of the mixtur e?
e. 15% (-) isomer / 85% (+) isomer
85% (-) isomer / 15% (+) isomer
40% (-) isomer / 60% ( +) isomer
60% (-) isomer / 40% (+) isomer
none of the above 12. Assign R /S configur ations to carbons A and B, respectively , in Penic illin V, shown below. For
your convenience, the molecule is show n twice so you can do your assignments separately . O O B A
C H3 N
H C H3
H O H H
S O S O B A C H3 N
H C H3
O OH O OH
a. R , R
b. R , S
c. S, R
d. S , S
e. can not be determined
from the information given 16. Treatment of 3- methy lcyclopentene with H g(OAc)2 in THF/H2O followed by N aBH4 produces
this/these produc t(s): A)
Both III and IV 2 17. Which w ould be the best method for conver ting A into B? A)
E) + H3O , heat
BH3/THF; then H2O2, H2O, OH
concd. H2SO4; then H2O, heat
Hg(OAc)2/TH F/H2O; then NaBH4
HBr; then NaOH /H2O 18. Treatmen t of 2-methy l-2-butene w ith Hg(OA c)2, in a TH F-ethano l mix ture, follow ed by N aBH4
produces which of the fo llow ing as a major product?
e. 19. Which of the following would be a reasonable synthesis of CH3CH2C H2CH2OH?
1 . H O +, ∆ 1 -bu ten e B) 1 -bu ten e C) 1 -bu ten e 3 1 . BH 3/TH F
2 . Na OH , H 2O 2, H 2O
1 . Hg (O Ac) 2/ TH F/H 2O 2. Na BH 4 D) More than one of these
E) None of these
20. Ignoring stereoisomers, how many different mono-alkenes (compounds containing one
double bond) would yield methylcyclopentane w hen treated with H2/Pt?
a. 1 b. 2
d. 4 e. none of the above
21. Which of the following has the smallest heat of hydr ogenation (i.e., leas t negative enthalpy of
a. b. c. d. 3 For each of the follow ing r eactions, the major produc t is shown. Indicate the preferred
reagent(s)/condition(s). Answer choices can be used more than once.
( d) H20, H2SO4, heat
1. BH3/TH F 2. NaOH, H2O2, H2O
1. H g(OAc)2, H2O/TH F; 2. NaBH4
OH 24. 25. The compound, cis-1,2-diethy lcyclopropane contains ___________ carbons , but overall is
a(n) _____________ molecule.
d. chiral, chiral
no chiral, chiral
no chiral, achiral 27. For the reac tion of 2- methylpropene w ith H Br in solvent methanol, which of the follow ing is a
correct depiction of a s tep in the major reaction pathway? a.
H H + Br Br B r- b. c. d. + H
O C H3OH C H3OH B r- H
O 4 28. For the reac tion of 2- methylpropene w ith Br2 in solvent H2O, which of the following is a correct
depiction of a s tep in the major reac tion pathway?
Br + Br Br B r- Br b.
H OH O H2 Br OH 2 c.
H OH Br Br Br d.
H OH OH 2 29. For the reac tion of 2- methylpropene w ith Br2 in solvent CH2Cl2, w hich of the following is a
correct depiction of a s tep in the major reaction pathway?
Br Br Br c.
Br Br Br
d. + B r- + Br- + Br- Br
Br Br 1. e 2. b 3. b 4. a 5. b 6. c 7. e 8. c 9. e
13, 14 & 15 deleted 16. e 17. d 18. b 19. b 20. d
24. a 25. b 26. deleted 27. d 28. c 29. a Br + B r- 10. d 11. d 12. b
21. c 22. c 23. b 5 ...
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