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學士後西醫-有機化學題庫  下載題庫

96 年 - 96學士後西醫-有機化學 #37201　

1.1. The Keq for the interconversion for the two chair forms of methylcyclohexane at 25 °C is 18. What % of the chair conformations feature an axial methyl group?
(A) 95
(B) 75
(C) 50
(D) 25
(E) 5

2.2. What is the name of the major organic product of the following reaction?

(A) 3,3-dimethyl-1-butanol
(B) 3,3-dimethyl-2-butanol
(C) 2,3-dimethyl-2-butanol
(D) 2,3-dimethyl-1-butanol
(E) 4-methyl-2-petanol

3.3. How many diastereomer(s) exist for the compound below?

(A) 2
(B) 4
(C) 6
(D) 8
(E) 0

4.4. Which of the following statements is (are) true for the Diels-Alder reaction?
(A) When the diene is electron-rich, the reaction works best when the dienophile contains one or more electron-withdrawing groups conjugated to its C=C.
(B) Substituents which are cis in the dienophile remain cis in the product.
(C) Dienes which cannot achieve an s-cis conformation do not react in Diels-Alder reactions.
(D) Secondary orbital interactions typically cause the endo product to be favored kinetically over the exo.
(E) All of the above.

5.5. What is the major product of the following reaction?

6.6. Which sequence of reagents works best to convert 3-hexene to 3-hexyne?
(A) 1. HCl 2. NaNH₂
(B) 1. BH₃．THF 2. HO- , H₂O₂ 3. NaNH₂
(C) 1. NaNH₂ 2. HI 3. H₃O⁺
(D) 1. Br₂, CH₂Cl₂ 2. NaNH₂ (excess)
(E) 1. Cl₂, CH₂Cl₂ 2. NaCN(excess)

7.7. Which of the following technique(s) can readily distinguish between:

(A) NMR
(B) IR
(C) MS
(D) A and B
(E) A and C

8.8. What is the major product of the following reaction?

9.9. What is the major product of the following reaction?

10.10. What is the major product from the following rearrangement?

11.11. At what position of the pyridine ring in the coenzyme below will oxidation-reduction reaction take place?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

12.12. Which of the following reaction is called Knoevenagel reaction?

13.

13. Which of the following structures is a Fischer projection of (2R,3R,4S)-2,3,4-tribromoheptane?
(A)
(B)
(C)
(D)
(E) None of the above

14.14. Arrange the following substrates in order of their increasing S_N2 reactivity with NaCN: (I) 1-bromopentane, (II) 1-chloro-2,2-dimethylpentane, (III) 2-bromo-2-methylpentane, and (IV) 1-chloro-3,3-dimethylpentane.
(A) IV < II < I < III
(B) III < I < IV < II
(C) IV < II < III < I
(D) III < II < IV < I
(E) None of the above

15.15. Both [E]- and (Z)-hex-3-ene can be treated with D2 in the presence of a platinum catalyst. How are the products from these two reactions related to each other?
(A) The [E]- and (Z)-isomers generate the same products but in differing amounts.
(B) The [E]- and (Z)-isomers generate the same products in exactly the same amounts.
(C) The products of the two isomers are related as constitutional isomers.
(D) The products of the two isomers are related as diastereomers.
(E) The products of the two isomers are related as enantiomers.

16.16. Consider the data illustrated below. The formula of unknown compound is C₉H₉N IR (cm^-1): 3050, 2950, 2240, 1630 ¹H NMR (δ): 7.5 (2H, d), 7.1 (2H, d), 2.3 (2H, q), 0.9 (3H, t) ¹³C NMR (δ): 137 (s), 130, (s), 126 (d), 122 (d), 95 (s), 25 (t), 15 (q) The structure of unknown compound is?
(A)

(B)

(C)

(D)

(E)

17.17. In electrophilic aromatic substitution reactions, the hydroxyl group is an o,p-director because:
(A) it donates electron density to the ring by induction and destabilizes the meta sigma complex.
(B) it donates electron density to the ring by induction and stabilizes the ortho and para sigma complexes.
(C) it donates electron density to the ring by resonance and destabilizes the meta sigma complex.
(D) it donates electron density to the ring by resonance and stabilizes the ortho and para sigma complexes.
(E) None of the above.

18.18. (S)-2-Methylbutanal __________ upon sitting in an acidic or a basic aqueous solution.
(A) racemizes
(B) esterifies
(C) inverts completely to the R configuration
(D) hydrolyzes
(E) irreversibly forms the hydrate

19.19. When a carbonyl is part of a conjugated π-network, the C=O stretch:
(A) has a higher frequency than in a nonconjugated system.
(B) has a lower frequency than in a nonconjugated system.
(C) always occurs at 1710 cm^-1 .
(D) occurs around 2700 cm^-1 .
(E) cannot be distinguished from the C=O stretch in a nonconjugated system.

20.20. When pent-1-ene is treated with mercury(II) acetate in methanol and the resulting product is reacted with NaBH₄, what is the primary organic compound which results?
(A) 3-ethoxypentane
(B) 1-methoxypentane
(C) 1-ethoxypentane
(D) 2-ethoxypentane
(E) 2-methoxypentane

21.21. What is the major product of the following reaction?

(A) I
(B) II
(C) III
(D) IV
(E) None of the above.

22.22. Which of the following terms describes the mechanism of a Claisen rearrangement reaction?
(A) Electrophilic addition
(B) Nucleophilic addition
(C) syn Elimination
(D) Radical substitution
(E) Pericyclic reaction

23.23. What is the major organic product obtained from the following reaction?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

24.24. What is the major organic product obtained from the following sequence of reactions?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

25.25. What is the major product of the following reaction?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

26.26. Which of the following terms best describes the compound shown below?

(A) a lecithin
(B) a diterpene
(C) a steroid
(D) a glyceride
(E) a prostaglandin

27.27. What configurations are found in the product(s) of the reaction shown below?

(A) 1R, 2R only
(B) 1S, 2S only
(C) 1R, 2S only
(D) An equal mixture of 1R, 2R and 1S, 2S
(E) An equal mixture of 1R, 2R and 1R, 2S

28.28. Which of the following statements correctly describes the molecule shown below?

(A) It is achiral
(B) It is meso
(C) Its asymmetric center possesses the R configuration
(D) The mirror image of this molecular is its enantiomer
(E) The molecule possesses enantiotopic hydrogens

29.29. Which of the following m/z values is the base peak for benzyl alcohol?
(A) 17
(B) 52
(C) 77
(D) 91
(E) 108

30.30. What splitting pattern is observed in the proton NMR spectrum for the indicated hydrogens?

(A) Singlet
(B) Doublet
(C) Triplet
(D) Singlet of singlet
(E) Multiplet

31.31. The Hell-Volhard-Zelinsky reaction involves:
(A) α-Bromination of carboxylic acids
(B) α-Bromination of ketones
(C) Formation of α, β -unsaturated carboxylic acids
(D) Formation of β-ketoesters
(E) Formation of amines

32.32. Which of the following reagents would reduce carboxylic acids and esters into alcohols?
(A) H₂/Ranney Ni
(B) 1) LiAlH₄; 2) H₃O⁺
(C) 1) NaBH₄; 2) H₃O⁺
(D) Na/NH₃
(E) Zn(Hg)/H⁺

33.33. Which of the following reducing agents is best used in the reaction shown below?

(A) H₂/Ranney Ni
(B) 1) LiAlH₄; 2) H₃O+
(C) 1) NaBH₄; 2) H₃O⁺
(D) Na/NH₃
(E) Zn(Hg)/H⁺

34.34. What is the systemic name of the following compound?

(A) 1-Azabicyclo[2,2,1]heptane
(B) 2-Azabicyclo[2,2,1]heptane
(C) 1-Azabicyclo[2,2,1]hexane
(D) 2-Azabicyclo[2,2,1]hexane
(E) 1-Azabicyclo[2,1,1]hexane

35.35. What is the name of the following reaction?

(A) Wittig reaction
(B) Michael reaction
(C) Dieckmann condensation
(D) Cope reaction
(E) Knoevenagel reaction

36.36. Which of the following lists the correct order of reactivity of the substrates in electrophilic aromatic substitution reactions?
(A) Thiophene > pyrrole > furan > benzene
(B) Benzene > thiophene > furan > pyrrole
(C) Furan > pyrrole > benzene > thiophene
(D) Pyrrole > furan > thiophene > benzene
(E) Benzene > furan > pyrrole > thiophene

37.37. In the addition of HBr to alkynes in the absence of peroxides, which of the following species is believed to be an intermediate?
(A) Vinyl anion
(B) Vinyl cation
(C) Vinyl radical
(D) Carbene
(E) Bromonium ion

38.38. Which of the following statements about propene is correct?
(A) All of the hydrogen atoms are in the same plane
(B) The compound has a cis and trans isomer
(C) It generally acts as a Lewis acid
(D) There is a total of eight sigma bonds
(E) All the carbon atoms are sp2 hybridized

39.39. The t-butoxycarbonyl group (Boc) is a widely used protecting group for primary amine and secondary amine. What reagent is commonly used for deprotection of N-Boc group in the Merrifield solid phase peptide synthesis?
(A) OH^-
(B) Pd/C, H₂
(C) Pd(OH)₂/C, H₂
(D) Acetic acid
(E) CF₃COOH

40.40. Predict the product of the following reaction:

(A)

(B)

(C)

(D)

(E) None of the above

41.41. The best method for preparation nonhalogenated cyclopropanes is by a process called the _________ reaction.
(A) Claisen rearrangement
(B) Schmidt
(C) Curtius
(D) Pauson-Khand
(E) Simmon-Smith

42.42. In the following structures, the general structure of sulfone is _________.

(A) A
(B) B
(C) C
(D) D
(E) E

43.43. What is the major organic product of the following sequence of reactions?

44.44. Choose the best reagent for carrying out the following conversion.

(A) 1. PhMgBr, ether; 2. H₃O⁺
(B) 1. PhCH₂MgBr, ether; 2. H₃O⁺
(C) (C₆H₅)₃P=CHC₆H5, THF
(D) Li(C₆H₅)₂Cu, ether
(E) None of the above

45.45. From the structures (I-IV) giving below which one belongs to nucleotide.

(A) I
(B) II
(C) III
(D) IV
(E) None of the above

46.46. What fragment ion (m/z) is produced from McLafferty rearrangement of 5-methyl-2-hexanone in EI-MS?
(A) 114
(B) 43
(C) 58
(D) 108
(E) None of the above

47.47. Select the most reasonable formula for the compounds with the following mass spectral data: M⁺ at m/z = 136 and M⁺² at m/z = 138 of approximately equal intensity.
(A) C₆H₁₃OCl
(B) C₄H₉Br
(C) C₁₀H₁₆
(D) C₉H₁₂O
(E) None of the above

48.48. If a compound has the –OH, –OCH₃, and –CHO groups all attached to a single benzene ring, the IUPAC name of the compound is based on which of the following?
(A) Anisole
(B) Benzaldehyde
(C) Phenol
(D) Methylether
(E) Phenyl

49.49. Which one of the following would NOT be a suitable solvent for Grignard reagents?
(A) Diethyl ether
(B) Tetrahydrofuran (THF)
(C) Ethanol
(D) Hexane
(E) They would all be suitable solvents

50.50. (S) (+)-Butanol shows a specific rotation at +13.52^o . What is the ratio of (S) (+)-butanol and (R) (-)-butanol when the measured rotation equals to +6.76^o ?
(A) (S) : (R) = 4 : 1
(B) (S) : (R) = 2 : 1
(C) (S) : (R) = 1 : 2
(D) (S) : (R) = 1 : 2.5
(E) (S) : (R) = 3 : 1

51.51. Consider the SN₁ reaction of tert-butyl chloride with iodide ion: (CH₃)₃C-Cl + I ^- → (CH₃)₃C-I + Cl^- If the concentration of iodide ion is doubled, the rate of forming tert-butyl iodide will:
(A) Double
(B) Increase 4 times
(C) Remain the same
(D) Decrease
(E) Triple

52.52. Which of the following functional groups would NOT show an IR absorbance above 3000 cm^-1?
(A) An amine (NH₂)
(B) A carbonyl (C=O)
(C) An alcohol (OH)
(D) A vinylic carbon-hydrogen bond (=C-H)
(E) A methylene hydrogen (-CH₂-)

53.53. Which part of the electromagnetic spectrum interacts with the nuclear spins of protons ?
(A) Radio Waves
(B) X-Ray radiation
(C) Visible Light
(D) Infrared radiation
(E) Ultra violet light

54.54. The pinacol rearrangement proceeds via intermediate.
(A) carbanion
(B) carbocation
(C) radical
(D) carbene
(E) neutral

55.55. Which carbon in the following sugar is the anomeric carbon atom?

(A) a
(B) b
(C) c
(D) d
(E) e

56.56. A tree diagram for the splitting of a proton Ha is reproduced below. What is the origin of this splitting pattern?

(A) Ha is coupled to two nonequivalent hydrogens with identical coupling constants.
(B) Ha is coupled to two nonequivalent hydrogens with different coupling constants.
(C) Ha is coupled to three nonequivalent hydrogens with identical coupling constants.
(D) Ha is coupled to three nonequivalent hydrogens with different coupling constants.
(E) Ha is coupled to three equivalent hydrogens with identical coupling constants.

57.57. Which of the following combinations of reactants would produce a meso compound?
(A) Cis-3-hexene and Br₂
(B) Trans-3-hexene and Br₂
(C) Cis-3-hexene and Br₂ in H₂O
(D) Trans-3-hexene and Br₂ in H₂O
(E) Trans-3-hexene and H₂/Pd/C

58.58. What is the product of the following sequence of reactions?

(A) 1,1-Diethylcyclopropane
(B) Cis-1,2-diethylcyclopropane
(C) Trans-1,2-diethylcyclopropane
(D) Cis and trans-1,1-diiodo-2,3-diethylcyclopropane
(E) Cis-1,2-diethyl-3,3-diiodocyclopropane

59.59. An unknown hydrocarbon shows a parent peak on the mass spectra at m/z = 86. There is no evidence of absorption from visible or UV spectra. The IR shows no major absorption outside the C-H stretch and bending vibration. The ¹ H NMR reveals a singlet at δ 0.9 (9H), a triplet at 0.98 (3H) and a quartet at 1.6 (2H). Which compound below best fits the description?

60.60. Which statement is correct for the reaction shown below? 1-chloro-2,4-dinitrobenzene + NaOH → 2,4-dinitrophenol
(A) This reaction is an electrophilic aromatic substitution.
(B) This reaction is a SN1 substitution.
(C) This reaction is a nucleophilic aromatic substitution.
(D) Substituted benzyne is the reaction intermediate.
(E) None of the above. II. Choose one correct answer for the following questions

61.

【單選題】每題 2 分，共計 40 分，答錯一題倒扣 0.5 分，倒扣至本大題零分為止，未作答，不給分亦不扣分。

61. What is the product of the following reaction?

62.62. What is the major product of the following reaction?

63.63. What is the major product of the following reaction?

64.

64. Which of the following compounds is the major organic product generated in the reaction below? Pay particular attention to region- and stereochemical detail.

(A)

(B)

(C)

(D)

(E) None of the above.

65.65. Which of the following series of synthetic steps could be used to carry out the transformation shown below?

(I) NaOH, (II) HCl, (III) PCC, (IV) O₃, (V) S(CH₃)₂, (VI) H₂O₂, NaOH
(A) II → IV → V
(B) III → V → I
(C) IV → VI → III
(D) IV → V → I
(E) None of the above.

66.66. What is the major organic product obtained from the following reaction?

(A) 1
(B) 2
(C) 3
(D) 4
(E) 5

67.67. Which of the following statements correctly describes the molecule shown below?

(A) Its C-4 NH₂ is strongly basic while the C-1 NH₂ is weekly acidic.
(B) Its C-4 NH₂ is weekly basic while the C-1 NH₂ is strongly acidic.
(C) Its C-4 NH₂ is weekly basic while the C-1 NH₂ is weekly acidic.
(D) Its C-4 NH₂ is strongly basic while the C-1 NH₂ is strongly acidic.
(E) Both C-1 NH₂ and the C-4 NH₂ are weekly basic.

68.68. Which of the compounds below undergoes solvolysis in aqueous ethanol most rapidly?
(A) Cyclohexyl bromide
(B) Isopropyl chloride
(C) Methyl iodide
(D) 3-Chloropentane
(E) 3-Iodo-3-methyl pentane

69.69. Which of the following E, Z designation are incorrect?

(A) AB
(B) BC
(C) CD
(D) AD
(E) AC

70.70. Provide structure for compound A in the following reaction scheme:

(A) A
(B) B
(C) C
(D) D
(E) None of the above

71.71. What is the major organic product of the following sequence of reactions?

72.72. What product would you obtain from Claisen condensation of ethyl propanoate?
(A) Ethyl 2-ethyl-3-oxopentanoate
(B) Propyl 2-methyl-3-oxopentanoate
(C) Ethyl 2-methyl-3-oxohexanoate
(D) Propyl 2-methyl-3-oxohexanoate
(E) Ethyl 2-methyl-3-oxopentanoate

73.73.What is the major organic product of the reaction shown below?

(A) Ethyl benzoate
(B) Phenyl propionate
(C) Diphenyl ketone
(D) Phenyl vinyl ketone
(E) An phenylseleno ketone

74.74. Which of the following reactions has a mechanism that involves the formation of a cyclic intermediate from acyclic starting materials?
(A) Dehydration of an alcohol
(B) Addition of HBr to an alkene
(C) Chlorination of an alkane
(D) Addition of bromine to an alkene
(E) Addition of Grignard to ketone

75.75. Which of the following substituents would have the lowest Cahn-Ingold-Prelog priority?
(A) -CH₂OH
(B) -CH₂COOH
(C) -CH₂CH₂Cl
(D) -CH₂NH₂
(E) -CH₂CH₂Br

76.76. Which sets of reagents would give the correct product for this reaction?

(A) Hg(OCOCF₃)₂in MeOH
(B) 1. Hg(OAc)₂ in THF/H₂O₂, 2. NaBH₄
(C) 1. BH₃, 2. NaOH, H₂O₂
(D) 1. BH₃, 2. H₂O₂, OH^- , 3. NaH, 4. CH₃I
(E) H⁺ , CH₃OH

77.77. The Frost circle can be used to reproduce the molecular orbital energies of a cyclic polyene. What species would be described by the Frost circle to the right?