Test Bank For Organic Chemistry 7th Edition by L. G. Wade Jr. test bank

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Test Bank For Organic Chemistry 7th Edition by L. G. Wade Jr. test bank 

Organic Chemistry, 7e (Wade)

Chapter 6   Alkyl Halides: Nucleophilic Substitution and Elimination

 

1) Which of the following best describes the carbon-chlorine bond of an alkyl chloride?

1. A) nonpolar; no dipole
2. B) polar; d+ at carbon and d- at chlorine
3. C) polar; d- at carbon and d+ at chlorine
4. D) ionic
5. E) none of the above

Answer:  B

Diff: 1

Section: 

 

2) Which of the following is classified as a vinylic halide?

1. A) CH3CH=CHOH
2. B) CH3CH=CHCl
3. C) CH3CH=CHCH2Cl
4. D) CH3CH2CH2CH2Br
5. E) BrCH2CH=CH2

Answer:  B

Diff: 1

Section: 

 

3) The flame retardant below has been found to be an androgen agonist and may have a contribution to an increasing rate of occurrence of prostate cancer (J. Med. ;2006, 7366).  What is the correct term that describes the relative position of the bromides in this structure?

 

 

1. A) geminal
2. B) vinyl
3. C) vicinal
4. D) aryl

Answer:  C

Diff: 1

Section: 

 

4) What general classification is given to the molecule below?

 

1. A) primary chloride
2. B) secondary chloride
3. C) tertiary chloride
4. D) vinyl chloride
5. E) benzyl chloride

Answer:  C

Diff: 1

Section: 

 

5) Which of the following is a geminal dihalide?

1. A) cis-1,2-dibromocyclopentane
2. B) 3,3-dichloropentane
3. C) trans-1,4-diiodocyclohexane
4. D) isobutyl chloride
5. E) 1,3-dibromoheptane

Answer:  B

Diff: 2

Section: 

 

6) Which of the following is a vicinal dihalide?

1. A) cis-1,2-dibromocyclopentane
2. B) 3,3-dichloropentane
3. C) trans-1,4-diiodocyclohexane
4. D) isobutyl chloride
5. E) 1,3-dibromoheptane

Answer:  A

Diff: 2

Section: 

 

7) Which of the following is a secondary alkyl halide?

1. A) methyl bromide
2. B) isopropyl chloride
3. C) t-butyl iodide
4. D) propyl bromide
5. E) isobutyl chloride

Answer:  B

Diff: 2

Section: 

 

8) Which of the following is a primary alkyl halide?

1. A) methyl bromide
2. B) isopropyl bromide
3. C) t-butyl iodide
4. D) cyclohexyl bromide
5. E) isobutyl chloride

Answer:  E

Diff: 2

Section: 

 

9) What is the IUPAC name of the compound shown below?

1. A) (1S,3S)-1,3-dichloro-1-ethyl-3-methylcyclopentane
2. B) (1R,3S)-1,3-dichloro-1-methyl-3-ethylcyclopentane
3. C) (1R,4S)-1,4-dichloro-1-ethyl-4-methylcyclopentane
4. D) (1R,3S)-1,3-dichloro-1-ethyl-3-methylcyclopentane
5. E) (1S,3R)-1,3-dichloro-3-ethyl-1-methylcyclopentane

Answer:  D

Diff: 2

Section: 

 

10) What is the IUPAC of the compound shown below?

 

1. A) (2R,3S,4S)-2-chloro-3,4-dibromo-3-methylhexane
2. B) (2R,3S,4S)-3,4-dibromo-2-chloro-3-methylhexane
3. C) (3S,4S,5S)-3,4-dibromo-5-chloro-4-methylhexane
4. D) (2R,3R,4S)-3,4-dibromo-2-chloro-3-methylhexane
5. E) (2R,3S,4R)-3,4-dibromo-2-chloro-3-methylhexane

Answer:  B

Diff: 2

Section: 

 

11) Provide the name of the bromoalkane shown below.

 

Answer:  3-bromo-4-ethylheptane

Diff: 1

Section: 

 

12) Draw the structure of cis-1,3-dichlorocyclopentane.

Answer:

Diff: 1

Section: 

 

13) Provide an acceptable name for CHCl3.

Answer:  chloroform or trichloromethane

Diff: 1

Section: 

 

14) Provide an acceptable name for CH3CH2CH2C(CH3)2I.

Answer:  2-iodo-2-methylpentane

Diff: 1

Section: 

 

15) Provide an acceptable name for the compound shown below.

 

Answer:  cis-1, 2-dichlorocyclopentane

Diff: 1

Section: 

 

16) Provide the structure of isopropyl iodide.

Answer:  (CH3)2CHI

Diff: 1

Section: 

 

17) Provide an acceptable name for the compound shown below.

 

Answer:  4-bromo-1,1-dimethylcyclohexane

Diff: 2

Section: 

 

18) Provide the structure of 1-bromo-3-methylhexane.

Answer:  CH3CH2CH2CH(CH3)CH2CH2Br

Diff: 2

Section: 

 

19) Which of the following best describes DDT?

1. A) a chlorocarbon used to decaffeinate coffee beans
2. B) a polybrominated organic compound used as a herbicide
3. C) a Freon used as a foaming agent
4. D) a mixed alkyl halide used as an anesthetic
5. E) a polychlorinated organic compound used as an insecticide

Answer:  E

Diff: 2

Section: 

 

20) The term CFC is an abbreviation for __________.

Answer:  chlorofluorocarbon

Diff: 1

Section: 

 

21) Which of the following alkyl halides has the smallest molecular dipole moment?

1. A) CH3F
2. B) CH3Cl
3. C) CH2I2
4. D) CH2Cl2
5. E) CF4

Answer:  E

Diff: 2

Section: 

 

 

22) Although F is more electronegative than Cl, the C-Cl bond has a larger dipole moment than the C-F bond. Explain.

Answer:  The bond dipole moment is determined by a product of the amount of charge separation and the distance over which the charge is separated, μ = x δ x d. Although δ is larger in the C-F bond, the greater length of the C-Cl bond ultimately makes its dipole moment larger.

Diff: 3

Section: 

23) Among the following alkyl halides, choose the one with the lowest boiling point.

1. A) t-butyl chloride
2. B) n-butyl chloride
3. C) t-butyl bromide
4. D) n-butyl iodide
5. E) t-butyl iodide

Answer:  A

Diff: 2

Section: 

 

24) Arrange the following alkyl halides in order of increasing boiling point:

CH3CH2Br, CH3CH2CH2Br, (CH3)2CHBr, CH3CH2F.

Answer:  CH3CH2F < CH3CH2Br < (CH3)2CHBr < CH3CH2CH2Br

Diff: 2

Section: 

 

25) When water is shaken with dichloromethane, a two-phase system results. Which compound forms the upper phase? Explain.

Answer:  Water is less dense than dichloromethane and therefore forms the upper phase.

Diff: 2

Section: 

 

26) When 2,2-dimethylbutane is subjected to free-radical chlorination, __________ distinct monochlorinated products are possible and __________ of these contain asymmetric carbon atoms.

1. A) 4, 2
2. B) 5, 0
3. C) 3, 0
4. D) 5, 2
5. E) 4, 0

Answer:  A

Diff: 2

Section: 

 

27) Draw two reasonable resonance structures and the hybrid of the intermediate formed in the following reaction.

 

Answer:  Free Radical mechanism at the allylic C’s

 

Diff: 2

Section: 

 

28) Provide the major organic product of the reaction below.

 

Answer:

Diff: 2

Section: 

 

29) Draw the structures of the two major products formed in the following reaction.

Indicate which of the two structures would be predicted to predominate under thermodynamic condition and explain why.

 

Answer:  Reactivity of allylic hydrogens due to resonance stability of the radical intermediate would result in the the formation of two major substitution products:

 

1                                     2

Product #2  (1-bromomethyl-cyclohexene) would be predicted to predominate in this reaction because it would form the more substituted ; However, radical characterists on the secondary carbon may lead to a significant formation of product #1

Diff: 3

Section: 

 

30) Provide the structure of the major organic product in the reaction below.

 

Answer:

Diff: 2

Section: 

 

31) Provide the structure of the major organic product in the reaction below.

 

Answer:

Diff: 2

Section: 

 

32) What type of intermediate is present in the SN2 reaction of cyanide with bromoethane?

1. A) carbocation
2. B) free radical
3. C) carbene
4. D) carbanion
5. E) This reaction has no intermediate.

Answer:  E

Diff: 2

Section: 

 

33) Consider the reaction of (CH3)3CO- with iodomethane. Will the reaction rate increase, decrease, or remain the same if the concentration of iodomethane is increased? Explain.

Answer:  This is an SN2 reaction with a rate = k[(CH3)3CO-] [CH3I]. The reaction rate will increase as [CH3I] increases.

Diff: 1

Section: 

 

34) Provide a detailed, stepwise mechanism for the reaction below.

 

(CH3)2CHCH2CH2CH2I  +  CN-  →  (CH3)2CHCH2CH2CH2CH2CN  +  I-

 

Answer:

Diff: 2

Section: 

 

 

35) Provide the structure of the major organic product that results when the reagents below are combined, and name the mechanism through which this reaction is proceeding.

 

CH3CºC:-Na+  +  CH3CH2CH2I

Answer:  CH3CºCCH2CH2CH3, SN2

Diff: 2

Section: 

36) Provide the structure of the major organic product in the following reaction.

 

(CH3)3N  +  CH3CH2CH2I  →

Answer:  [(CH3)3NCH2CH2CH3]+ I-

Diff: 2

Section: 

 

37) Which of the following species is the least nucleophilic?

1. A) H2O
2. B) BF3
3. C) (CH3)3N
4. D) CH3O-
5. E) CN-

Answer:  B

Diff: 2

Section: 

 

38) Which of the following compounds is the most nucleophilic?

1. A) CH3SH
2. B) CH3OH
3. C) H2O
4. D) CH3CO2H
5. E) BF3

Answer:  A

Diff: 2

Section: 

 

39) Which of the following solvents could be described as polar and protic?

1. A) ethanol
2. B) acetonitrile
3. C) dimethylformamide
4. D) acetone
5. E) 18-crown-6

Answer:  A

Diff: 3

Section: 

 

 

40) Name one factor that is favorable for nucleophilicity but not for basicity.

Answer:  polarizability

Diff: 2

Section: 

 

41) Arrange the following species in order of increasing nucleophilicity:

CH3CH2S-, CH3CH2O-, (CH3)3CO-, (CH3)3COH.

Answer:  (CH3)3COH < (CH3)3CO- < CH3CH2O- < CH3CH2S-

Diff: 2

Section: 

42) Which halide is a better nucleophile, iodide or fluoride?  Explain.

Answer:  The iodide ion is the better ; The larger size of this ion renders its electron cloud more polarizable.

Diff: 2

Section: 

 

43) Which is more nucleophilic, t-butoxide or ethoxide?  Explain.

Answer:  Ethoxide is the better ; The steric bulk of t-butoxide decreases its effectiveness as a nulcoephile.

Diff: 2

Section: 

 

44) Rank the species below in order of increasing nucleophilicity in hydroxylic solvents:

CH3CO2-, CH3S-, HO-, H2O.

Answer:  H2O  <  CH3CO2-  <  HO-  <  CH3S-

Diff: 2

Section: 

 

45) What type of solvent is best for SN2 reactions which employ anionic nucleophiles: polar, protic solvents; polar, aprotic solvents; or nonpolar solvents? Explain.

Answer:  Polar, aprotic solvents are best. These solvents have strong dipole moments to enhance solubility of the anionic species but lack the ability to solvate the anion by hydrogen bonding.

Diff: 3

Section: 

 

46) Which of the following compounds will undergo an SN2 reaction most readily?

1. A) (CH3)3CCH2I
2. B) (CH3)3CCl
3. C) (CH3)2CHI
4. D) (CH3)2CHCH2CH2CH2I
5. E) (CH3)2CHCH2CH2CH2Cl

Answer:  D

Diff: 2

Section: 

 

47) Which of the following alkyl chlorides will undergo SN2 reaction most readily?

1. A) 1-chloro-4-methylpentane
2. B) 2-chloro-4-methylpentane
3. C) 2-chloro-3-methylpentane
4. D) 3-chloro-2-methylpentane
5. E) 2-chloro-2-methylpentane

Answer:  A

Diff: 2

Section: 

48) Arrange the following substrates in order of their increasing SN2 reactivity with NaCN:

bromoethane, 1-chloro-3,3-dimethylpentane, 1-chloro-2,2-dimethylpentane, and 2-bromo-2-methylpentane.

Answer:  2-bromo-2-methylpentane < 1-chloro-2,2-dimethylpentane < 1-chloro-3,3-dimethylpentane < bromoethane

Diff: 2

Section: 

 

49) List the following bromides in order of their increasing reactivity as substrates in SN2 reactions:  PhBr, PhCH2Br, and PhCH(CH3)Br.

Answer:  PhBr < PhCH(CH3)Br < PhCH2Br

Diff: 2

Section: 

 

50) List the following bromides in order of their increasing reactivity as substrates in SN2 reactions:  2-chlorobutane, 2-iodobutane, and 1-iodobutane.

Answer:  2-chlorobutane < 2-iodobutane < 1-iodobutane

Diff: 2

Section: 

 

51) Do all primary iodides react with N3- at the same rate via the SN2 mechanism?  Explain.

Answer:  No, not all primary alkyl react with N3- at the same rate via the SN2 ; Some primary iodides are more hindered than ; (CH3)3CCH2I and CH3CH2I are both primary, but (CH3)3CCH2I is significantly more ; Additionally, some primary iodides have increased activity due to a benzylic or allylic positioning.

Diff: 2

Section: 

 

52) Do all primary alkyl iodides undergo SN2 reactions with sodium cyanide in DMSO at identical rates? Explain.

Answer:  No. All primary iodides are not equally accessible to attack by the CN-. Steric hindrance varies among primary iodides.

Diff: 2

Section: 

 

 

53) Which of the following alkyl chlorides would undergo substitution most rapidly when treated with  ºCH chloroethane 2-chloropropane or 1-chloro-2,2-dimethylpropane  Provide the structure of the substitution product.

Answer:  CH3CH2CºCH

Diff: 2

Section: 

 

54) Show the best way to prepare CH3OCH(CH3)2 by an SN2 reaction.

Answer:  CH3I  +  NaOCH(CH3)2

Diff: 2

Section:  

55) SN2 reactions take place with __________ of stereochemistry at the center undergoing substitution.

Answer:  inversion

Diff: 1

Section: 

 

56) Complete the following SN2 reaction by providing structures for the necessary starting materials.

 

 

 

Answer:

 

Diff: 2

Section: 

 

57) Provide the major organic product of the reaction below.

 

Answer:

Diff: 2

Section: 

 

58) Provide the major organic product of the reaction below.

 

Answer:

Diff: 2

Section: 

 

59) Provide the major organic product of the reaction below.

 

Answer:

Diff: 2

Section: 

 

60) Provide the structure of the major organic product which results when (S)-2-iodopentane is treated with KCN in DMF.

Answer:

Diff: 2

Section: 

 

61) Provide the structure of the major organic product in the following reaction.

 

Answer:

Diff: 2

Section: 

 

62) Which of the compounds below undergoes solvolysis in aqueous ethanol most rapidly?

1. A) cyclohexyl bromide
2. B) methyl iodide
3. C) isopropyl chloride
4. D) 3-chloropentane
5. E) 3-iodo-3-methylpentane

Answer:  E

Diff: 2

Section: 

 

63) Which of the following alkyl bromides undergoes solvolysis in aqueous methanol most rapidly?

1. A) PhCHBrCH3
2. B) (CH3)2CHCH2CH2Br
3. C) (CH3)2CHCH2CHBrCH3
4. D) CH3CH2CH2CH2Br
5. E) PhBr

Answer:  A

Diff: 2

Section: 

 

64) Rank the following molecules in order of increasing relative rate of SN1 solvolysis  with methanol and heat (slowest to fastest reacting).

1. A) 3 < 2 < 4 < 5 < 1
2. B) 2 < 3 < 4 < 1 < 5
3. C) 5 < 4 < 3 < 2 < 1
4. D) 2 < 3 < 4 < 5 < 1
5. E) 1 < 2 < 5 < 4 < 3

Answer:  B

Diff: 3

Section: 

 

65) Arrange the following compounds in order of increasing reactivity toward ethanol solvolysis:

t-butyl bromide, t-butyl iodide, isopropyl chloride, methyl iodide.

Answer:  methyl iodide < isopropyl chloride < t-butyl bromide < t-butyl iodide

Diff: 2

Section: 

 

66) List the following bromides in order of their increasing reactivity as substrates in SN1 reactions:  PhBr, PhCH2Br, and PhCH(CH3)Br.

Answer:  PhBr < PhCH2Br < PhCH(CH3)Br

Diff: 2

Section: 

 

67) List the following bromides in order of their increasing reactivity as substrates in SN1 reactions:  2-chlorobutane, 2-iodobutane, and 1-iodobutane.

Answer:  1-iodobutane < 2-chlorobutane < 2-iodobutane

Diff: 2

Section: 

 

68) List the following bromides in order of their increasing reactivity as substrates in SN1 reactions:  1-iodo-1-ethylcyclopentane, chlorocyclopentane, and iodocyclopentane.

Answer:  chlorocyclopentane < iodocyclopentane < 1-iodo-1-ethylcyclopentane

Diff: 2

Section: 

 

69) Draw the highest energy transition state in the solvolysis of (CH3)3CI in CH3OH.

Answer:

Diff: 2

Section: 

 

70) List the following compounds in order of increasing reactivity in an SN1 reaction.

 

CH3Br,  CH3CH2CH2I,  (CH3)3CI,  CH3CHBrCH3,  CH3CHICH3

Answer:  CH3Br  <  CH3CH2CH2I  <  CH3CHBrCH3  <  CH3CHICH3  <  (CH3)3CI

Diff: 2

Section: 

 

71) When t-butyl chloride undergoes solvolysis in a solvent mixture composed of 70% water/30% acetone, the reaction rate is slower then when the same compound is solvolyzed in 80% water/20% acetone. Explain.

Answer:  This is purely a solvent effect. The greater the percentage of water in this solvent mixture, the more polar the solvent. The more polar the solvent, the more easily solvated the developing carbocation and the more rapidly it is formed.

Diff: 3

Section: 

 

72) When ionization occurs at the single sterocenter of a chiral compound, the resulting carbocation is:

1. A) achiral
2. B) chiral
3. C) racemic
4. D) optically active
5. E) none of the above

Answer:  A

Diff: 2

Section: 

 

73) SN1 reactions usually proceed with:

1. A) equal amounts of inversion and retention at the center undergoing substitution.
2. B) slightly more inversion than retention at the center undergoing substitution.
3. C) slightly more retention then inversion at the center undergoing substitution.
4. D) complete inversion at the center undergoing substitution.
5. E) complete retention at the center undergoing substitution.

Answer:  B

Diff: 3

Section: 

 

74) If the absolute configuration at an asymmetric carbon does not change during the course of a reaction, the reaction is said to occur with __________ of stereochemistry.

Answer:  retention

Diff: 1

Section: 

 

75) Provide the structure of the major organic products which result in the reaction below.

 

Answer:

Diff: 2

Section: 

 

76) Provide two circumstances under which solvolysis of a chiral alkyl halide would not result in the generation of a mixture of enantiomeric products.

Answer:  Choose from among:

(i)   leaving group not bound to stereocenter

(ii)  rearrangement yields a carbocation in which two groups bound to the cationic center are the same

(iii) the molecule contains at least one additional stereocenter which is unaffected by the ionization

(iv)  rearrangement ultimately results in a meso compound

Diff: 3

Section: 

 

77) Which of the cations below would be subject to a structural rearrangement?

 

 

1. A) 1
2. B) 3
3. C) 1, 2, & 3
4. D) 2 & 3

Answer:  B

Diff: 2

Section: 

 

78) Which of the following alkyl halides is most likely to undergo rearrangement in an SN1 reaction?

1. A) 3-bromopentane
2. B) 2-chloro-3,3-dimethylpentane
3. C) 3-chloropentane
4. D) bromocyclohexane
5. E) 1-bromo-4-methylcyclohexane

Answer:  B

Diff: 2

Section: 

 

79) Which of the following alkyl chlorides is least likely to undergo rearrangement during a solvolysis reaction?

1. A) 2-chloro-4-methylpentane
2. B) 2-chloro-3-methylpentane
3. C) 2-chloro-2-methylpentane
4. D) cis-1-chloro-2-ethylcyclohexane
5. E) trans-1-chloro-2-ethylcyclohexane

Answer:  C

Diff: 2

Section: 

 

80) A sample of 1-chloro-1-phenylethane with an [α]25D of ; is reacted with NH3 in methanol/water ; The major substitution product of the reaction is 1-phenyl-1-ethylamine with an [α]25D of ;.  Given that optically pure (R) 1-chloro-1-phenylethane has a specific rotation of ; and  that optically pure (R) 1-phenyl-1-ethylamine has a specific rotation of +;, which of the following statements best describes this reaction?

1. A) Net inversion 25% with 75% racemization — SN1 mechanism
2. B) Net inversion 12% with 88% racemization — SN1 mechanism
3. C) Net inversion 75% with 25% racemization — SN2 mechanism
4. D) Net inversion 12% with 88% racemization — SN2 mechanism
5. E) Net inversion 88% with 12% racemization — SN2 mechanism

Answer:  A

Diff: 3

Section: 

 

81) Predict the structure of the expected product for the following reaction.

 

 

Answer:

 

Diff: 3

Section: 

 

82) Provide the major organic product of the reaction below and a detailed, stepwise mechanism which accounts for its formation.

 

Answer:

Diff: 3

Section: 

 

83) Provide the structure of the major organic product which results in the following reaction.

 

Answer:

Diff: 3

Section: 

 

84) Which of the following statements correctly describe(s) E1 reactions of alkyl halides (RX)?

 

1. Rate = k[base]
2. Rate = k[base][RX]

III.       Rate = k[RX]

1. The reactions occur in two or more distinct steps.
2. Rearrangements are sometimes seen.

 

1. A) II and IV
2. B) III and V
3. C) I, IV, and V
4. D) I only
5. E) III, IV, and V

Answer:  E

Diff: 2

Section: 

 

85) Why does CH2CHCHBrCH3 undergo solvolysis much more rapidly than 2-bromobutane?

Answer:  The intermediate carbocation is resonance stabilized.

Diff: 3

Section: 

 

86) When 1-bromo-2, 2-dimethylcyclopentane is heated in ethanol, one of the products which results is shown below. Provide a detailed, stepwise mechanism for the production of this compound, and give the name of the mechanism by which it is produced.

 

Answer:

Diff: 3

Section: 

 

87) Dehydration of 1-butanol with concentrated sulfuric acid at 140°C results in the formation of mainly ; According to these results, which of the following conclusions might be valid?

1. A) The reaction undergoes an E2-type elimination mechanism
2. B) The reaction follows a new mechanism involving the formation of a carbanion intermediate
3. C) The reaction undergoes an E1-type elimination mechanism in conjunction with a hydride shift
4. D) The reaction undergoes an E2-type elimination mechanism in conjunction with a methyl shift
5. E) The reaction undergoes an E1-type elimination mechanism with no shifting

Answer:  C

Diff: 3

Section: 

 

88) What is Zaitsev’s rule?

Answer:  In elimination reactions, the most highly substituted alkene product is the major product.

Diff: 2

Section: 

 

89) How many distinct alkene products are possible when the alkyl iodide below undergoes E2 elimination?

 

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

Answer:  E

Diff: 2

Section: 

 

90) Which of the following alkyl halides can produce only a single alkene product from when treated with sodium methoxide?

1. A) 2-chloro-2-methylpentane
2. B) 3-chloro-3-ethylpentane
3. C) 3-chloro-2-methylpentane
4. D) 2-chloro-4-methylpentane
5. E) 2-chloro-3-ethylpentane

Answer:  B

Diff: 2

Section: 

 

91) How many distinct alkene products results when 1-bromo-1-ethylcyclopenatne is treated with NaOCH3?

1. A) 1
2. B) 2
3. C) 3
4. D) 4

Answer:  B

Diff: 2

Section: 

 

 

92) Provide a structure for the major substitution and major elimination product resulting from the reaction below.

 

 

 

Answer:

 

Diff: 2

Section: 

93) Provide the structure of the major alkene product of the reaction below.

 

Answer:

Diff: 2

Section: 

 

94) Provide the major organic product of the reaction below.

 

Answer:

Diff: 2

Section: 

 

 

95) Provide a series of synthetic steps by which (CH3)2C=CH2 could be prepared from 2-methylpropane.

Answer:  1. Br2, hν

2. NaOCH3, CH3OH

Diff: 2

Section: 

 

96) Provide the structure of the major organic product which results when 2-bromo-2-methylbutane is treated with sodium ethoxide.

Answer:

Diff: 2

Section: 

97) When 1-iodo-1-methylcyclohexane is treated with NaOCH2CH3, the more highly substituted alkene product predominates. When KOC(CH3)3. is used instead, the less highly substituted alkene product predominates. Offer an explanation.

Answer:  The unhindered ethoxide procedures the more stable alkene product (ie, the more highly substituted alkene possible). When the bulky t-butoxide is used, the most accessible hydrogen is removed. This results in the least highly substituted alkene possible.

Diff: 3

Section: 

 

 

98) When (cis)-1-bromo-2 methylcyclohexane is treated with methanol and heat, four different  products are formed –  two by substitution and two by elimination.

 

Which of the following conditions would change the outcome of this reaction by promoting the production of 3-methylhexene as the major product?

 

1. A) KOH, ethanol and heat
2. B) water/acetone and heat
3. C) tert-butoxide/tert-butyl alcohol
4. D) tert-butyl alcohol and heat
5. E) methoxide/methanol

Answer:  C

Diff: 3

Section: 

 

99) Provide the major organic product of the reaction below.

 

Answer:

Diff: 2

Section: 

 

100) Provide the structure of the major organic product which results in the following reaction.

 

Answer:

Diff: 2

Section: 

 

101) Provide the structure of the major organic product which results in the following reaction.

 

Answer:

Diff: 2

Section: 

 

102) Provide the structure of the major organic product which results in the following reaction.

 

Answer:

Diff: 2

Section: 

 

103) Provide the structure of the major organic product which results in the following reaction.

 

Answer:

Diff: 3

Section: 

 

104) Which diastereomer of 1-bromo-4-t-butylcyclohexane, the cis or the trans, undergoes elimination more rapidly when treated with sodium ethoxide? Explain your answer.

Answer:  The cis isomer reacts more quickly. An axial orientation of the C-Br bond is required for E2 in six-membered ring systems. In order for this to occur in the trans isomer, the bulky

 t-butyl group must also assume an axial orientation; this requires substantial energy of activation.

Diff: 3

Section: 

 

105) Provide the structure of the major organic product in the following reaction.

 

Answer:

Diff: 3

Section: 

 

106) Provide the structure of the major organic product in the following reaction.

 

Answer:

Diff: 3

Section: 

 

107) Which of the following mechanisms (SN1, SN2, E1, E2) feature(s) a carbocation intermediate?

1. A) SN1 only
2. B) SN2 only
3. C) E1 only
4. D) E2 only
5. E) both SN1 and E1

Answer:  E

Diff: 1

Section: 

 

108) In which of the following mechanisms (SN1, SN2, E1, E2) are alkenes the major reaction products?

1. A) SN1 only
2. B) SN2 only
3. C) E1 only
4. D) E2 only
5. E) both E1 and E2

Answer:  E

Diff: 1

Section: 

 

 

109) Predict the most likely mechanism for the reaction shown below.

 

1. A) SN1
2. B) SN2
3. C) E1
4. D) E2
5. E) E1cb

Answer:  A

Diff: 2

Section: 

110) Predict the most likely mechanism for the reaction shown below.

 

1. A) SN1
2. B) SN2
3. C) E1
4. D) E2
5. E) E1cb

Answer:  D

Diff: 2

Section: 

 

111) Predict the two most likely mechanisms for the reaction of 2-iodohexane with sodium ethoxide.

1. A) SN2 and SN1
2. B) E1 and E2
3. C) SN2 and E2
4. D) E1 and SN1
5. E) E2 and SN1

Answer:  C

Diff: 2

Section: 

 

 

112) Predict the two most likely mechanisms which occur when 2-iodohexane is heated in ethanol.

1. A) SN2 and SN1
2. B) E1 and E2
3. C) SN2 and E2
4. D) E1 and SN1
5. E) E2 and SN1

Answer:  D

Diff: 2

Section: 

 

113) The major product from the reaction of 2-chloro-2-methylpentane with sodium ethoxide in ethanol results from which of the following mechanistic pathways?

1. A) SN1
2. B) SN2
3. C) E1
4. D) E2
5. E) E1cb

Answer:  D

Diff: 2

Section: 

114) The major product which results when 2-chloro-2-methylpentane is heated in ethanol is an ether. From which mechanistic pathway does this ether arise?

1. A) SN1
2. B) SN2
3. C) E1
4. D) E2
5. E) E1cb

Answer:  A

Diff: 2

Section: 

 

115) When 3-iodo-3-ethylpentane is treated with sodium methoxide in methanol, the major organic product is an __________ that is generated through an __________ mechanism.

1. A) ether, SN1
2. B) ether, SN2
3. C) ether, E1
4. D) alkene, E2
5. E) alkene, E1

Answer:  D

Diff: 2

Section: 

 

 

116) When 3-iodo-3-ethylpentane is heated in methanol, the major organic product is an __________ that is generated through an __________ mechanism.

1. A) ether, SN1
2. B) ether, SN2
3. C) ether, E1
4. D) alkene, E2
5. E) alcohol, E1

Answer:  A

Diff: 2

Section: