This document presents a series of practice problems for reactions involving alkenes. It includes 20 slides with questions about reaction mechanisms and predicting products. The exercises are part of a research project evaluating an interactive online tutorial on these topics. Users are asked to provide feedback by completing a short survey after working through the problems.

1. Prepared by Bill Weigel and Dr. Laurie Starkey
[Version 3.2]
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3. These exercises are part of research project being conducted at
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5. Reaction Reagents Added Groups Regioselectivity Stereoselectivity
Hydrohalogenations
HBr -H -Br Markovnikov Mixed
HBr, ROOR -H -Br Anti-Markovnikov Mixed
Halogenation Br2 -Br -Br N/A Anti
Halohydrin Formation Br2, H2O (or ROH) -Br -OH (or OR) "Markovnikov" Anti
Acid Catalyzed Hydration H2SO4, H2O -H -OH Markovnikov Mixed
Oxymercuration-Demercuration
1) Hg(Oac)2, H2O
-H -OH Markovnikov Anti
2) NaBH4
Hydroboration-Oxidation
1) BH3·THF, H2O
-H -OH Anti-Markovnikov Syn
2) H2O2, NaOH
Hydroxlyation KMnO4 or OsO4 -OH -OH N/A Syn
Epoxidation mCPBA (RCO3H) Epoxide Ring N/A Syn
Hydrogenation H2, Ni/Pt/Pd cat. -H -H N/A Syn
ContinuePrevious

6. For each transformation shown, propose an acceptable reaction mechanism. Be sure to use
proper arrow pushing, and include all lone pairs and formal charges.
A)
C) D)
B)
BA C D
Check Your Answers
1
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7. For each transformation shown, propose an acceptable reaction mechanism. Be sure to use
proper arrow pushing, and include all lone pairs and formal charges.
A)
C) D)
B)
BA C D
Check Your Answers
2
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8. Predict the product in each of following reactions.
A)
C) D)
B)
B DCA
Check Your Answers
3
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9. For each transformation shown, propose an acceptable reaction mechanism. Be sure to use
proper arrow pushing, and include all lone pairs and formal charges.
A)
C)
D)
For additional practice, determine if the products shown are chiral and if so, propose a
separate mechanism for the formation of its enantiomer.
B)
BA C D
Check Your Answers
4
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10. For each transformation shown, propose an acceptable reaction mechanism. Be sure to use
proper arrow pushing, and include all lone pairs and formal charges.
A) B)
C) D)
(±)
(±)
(±)(±)
BA C D
Check Your Answers
5
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11. Predict the major product(s) in each of the following reactions.
A)
B)
C)
E)
F)
D)
BA C D
Check Your Answers
E F
6
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12. D)
For each transformation shown, propose an acceptable reaction mechanism accounting for the
products shown. Be sure to use proper arrow pushing, and include all lone pairs and formal
charges.
Acid-Catalyzed Hydration
A)
B)
C)
BA C D
Check Your Answers
7
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13. Acid-Catalyzed Hydration
A)
B)
C)
D)
E)
F)
Predict the major product in each of the following reactions.
BA C D
Check Your Answers
E F
8
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14. Complete the mechanism pathway for the oxymercuration of propene by filling in the missing
arrows, lone pairs, and formal charges.
The reductive demercuration step involves a more complex mechanism pathway in which the acetomercury
group is displaced by a borohydride hydrogen. (You do not need to show this)
Oxymercuration-Demercuration
Check Answer
This reaction can be used to achieve “Markovnikov” additions of H2O
to an alkene without the possibility of rearrangements.
Explain why this is.
9
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15. Oxymercuration-Demercuration
A)
B)
C)
D)
Predict the major product in each of the following reactions.
BA C D
Check Your Answers
10
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16. Hydroboration-Oxidation of an alkene is a 2 step process as shown in the reaction above. Fill in
the missing intermediate compounds for the hydroboration portion of this reaction below. Use
arrows to account for the formation of the intermediates.
Hydroboration-Oxidation
Speculate as to why the successive intermediates become increasingly more regioselective for
the anti-markovnikov orientation.
Check Answer
11
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17. Hydroboration-Oxidation
Predict the major product in each of the following reactions.
A)
B)
D)
C)
E)
BA C D
Check Your Answers
E
12
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18. A)
B)
Predict the major product in each of the following reactions.
C)
D)
BA C D
Check Your Answers
13
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19. For each transformation shown, propose an acceptable chemical mechanism. Be sure to use
proper arrow pushing, and include all lone pairs and formal charges.
A)
B)
C)
D)
BA C D
Check Your Answers
14
NextBack

20. A)
B)
Predict the major product in each of the following reactions.
C)
D)
BA C D
Check Your Answers
15
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21. A)
B)
C)
Predict the major product in each of the following reactions.
D)
E)
F)
BA C D
Check Your Answers
E F
16
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22. Predict the major product in each of the following reactions.
BA C E
Check Your Answers
D
17
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23. Predict the major product in each of the following reactions.
BA C D
Check Your Answers
E F
18
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24. Predict the reagent(s) needed to accomplish the following transformations.
BA C D
Check Your Answers
E
19
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25. End of Exercises
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26. The next slides contain only the answers. There
are no more questions from this point forward.

27. Hydrohalogenation of Alkenes (I)
Exercise A
For each transformation make sure your mechanism correctly accounts for the Markovnikov
addition of HX.
Return to
Question

28. Hydrohalogenation of Alkenes (I)
(Exercise B)
For each transformation make sure your mechanism correctly accounts for the Markovnikov
addition of HX.
Return to
Question

29. Hydrohalogenation of Alkenes (I)
(Exercise C)
For each transformation make sure your mechanism correctly accounts for the Markovnikov
addition of HX.
Return to
Question

30. Hydrohalogenation of Alkenes (I)
Exercise DFor each transformation make sure your mechanism correctly accounts for the Markovnikov
addition of HX.
Return to
Question

31. Hydrohalogenation of Alkenes (II)
(Exercise A)
Each of the following mechanisms first involves homolytic cleavage of a peroxide and the
subsequent creation of a bromine radical:
Return to
Question

32. Hydrohalogenation of Alkenes (II)
(Exercise B)
Each of the following mechanisms first involves homolytic cleavage of a peroxide and the
subsequent creation of a bromine radical:
Return to
Question

33. Hydrohalogenation of Alkenes (II)
(Exercise C)
Each of the following mechanisms first involves homolytic cleavage of a peroxide and the
subsequent creation of a bromine radical:
Return to
Question

34. Hydrohalogenation of Alkenes (II)
(Exercise D)
Each of the following mechanisms first involves homolytic cleavage of a peroxide and the
subsequent creation of a bromine radical:
Return to
Question

35. Hydrohalogenation of Alkenes (III)
(Exercise A)
Return to
Question

36. Hydrohalogenation of Alkenes (III)
(Exercise B)
Return to
Question

37. Hydrohalogenation of Alkenes (III)
(Exercise C)
Return to
Question

38. Hydrohalogenation of Alkenes (III)
(Exercise D)
Return to
Question

39. Reactions Involving Halonium Ion Intermediates (I)
(Exercise A)
Return to
Question

40. Reactions Involving Halonium Ion Intermediates (I)
(Exercise B)
Return to
Question

41. Reactions Involving Halonium Ion Intermediates (I)
(Exercise C)
Return to
Question

42. Reactions Involving Halonium Ion Intermediates (I)
(Exercise D)
Return to
Question

43. Reactions Involving Halonium Ion Intermediates (II)
(Exercise A)
Return to
Question
Bromide and water have lone pairs that in theory can allow either to act as a lewis base. However, solvents
are typically present in large excess compared to reagents. In terms of probability, what would be the more
likely base, the solvent (H2O) or a reagent (Br-)?
When proposing deprotonations, also take into consideration the relative strengths of any proton acceptors
in solution. What will be more likely to perform deprotonation, water (a weak base) or bromide (the conj.
base of a strong acid)?

44. Reactions Involving Halonium Ion Intermediates (II)
(Exercise B)
Return to
Question
Bromide and water have lone pairs that in theory can allow either to act as a lewis base. However, solvents
are typically present in large excess compared to reagents. In terms of probability, what would be the more
likely base, the solvent (H2O) or a reagent (Br-)?
When proposing deprotonations, also take into consideration the relative strengths of any proton acceptors
in solution. What will be more likely to perform deprotonation, water (a weak base) or bromide (the conj.
base of a strong acid)?

45. Reactions Involving Halonium Ion Intermediates (II)
(Exercise C)
Return to
Question
Bromide and water have lone pairs that in theory can allow either to act as a lewis base. However, solvents
are typically present in large excess compared to reagents. In terms of probability, what would be the more
likely base, the solvent (H2O) or a reagent (Br-)?
When proposing deprotonations, also take into consideration the relative strengths of any proton acceptors
in solution. What will be more likely to perform deprotonation, water (a weak base) or bromide (the conj.
base of a strong acid)?

46. Reactions Involving Halonium Ion Intermediates (II)
(Exercise D)
Return to
Question
Bromide and water have lone pairs that in theory can allow either to act as a lewis base. However, solvents
are typically present in large excess compared to reagents. In terms of probability, what would be the more
likely base, the solvent (H2O) or a reagent (Br-)?
When proposing deprotonations, also take into consideration the relative strengths of any proton acceptors
in solution. What will be more likely to perform deprotonation, water (a weak base) or bromide (the conj.
base of a strong acid)?

47. Be mindful of the creation of chiral products and when this is the case, indicate so by either
drawing out both enantiomers or indicating the presence of the enantiomer.
Return to
Question
A)
Reactions Involving Halonium Ion Intermediates (III)
(Exercise A)

48. Be mindful of the creation of chiral products and when this is the case, indicate so by either
drawing out both enantiomers or indicating the presence of the enantiomer.
Return to
Question
B)
Reactions Involving Halonium Ion Intermediates (III)
(Exercise A)

49. Be mindful of the creation of chiral products and when this is the case, indicate so by either
drawing out both enantiomers or indicating the presence of the enantiomer.
Return to
Question
C)
Reactions Involving Halonium Ion Intermediates (III)
(Exercise C)

50. Be mindful of the creation of chiral products and when this is the case, indicate so by either
drawing out both enantiomers or indicating the presence of the enantiomer.
Return to
Question
D)
Reactions Involving Halonium Ion Intermediates (III)
(Exercise D)

51. Be mindful of the creation of chiral products and when this is the case, indicate so by either
drawing out both enantiomers or indicating the presence of the enantiomer.
E)
Return to
Question
Reactions Involving Halonium Ion Intermediates (III)
(Exercise E)

52. Be mindful of the creation of chiral products and when this is the case, indicate so by either
drawing out both enantiomers or indicating the presence of the enantiomer.
Return to
Question
F)
Reactions Involving Halonium Ion Intermediates (III)
(Exercise F)
The first step installs two leaving groups (the halogens) and the second step involves E2
between the base and each alkyl halide (two individual eliminations for each Cl).

53. Additions of H2O to Alkenes (I)
(Exercise A)
Be sure to correctly apply Markovnikov’s Rule in your mechanism. Ask the question “How can a
proton be added to the alkene in such a way that the resulting carbocation is in the more stable
location?”
Note how the acid-catalyzed mechanism begins with the consumption of the acid and ends with
its regeneration
Acid-Catalyzed Hydration
Return to
Question

54. Additions of H2O to Alkenes (I)
(Exercise B)
Be sure to correctly apply Markovnikov’s Rule in your mechanism. Ask the question “How can a
proton be added to the alkene in such a way that the resulting carbocation is in the more stable
location?”
Note how the acid-catalyzed mechanism begins with the consumption of the acid and ends with
its regeneration
Acid-Catalyzed Hydration
Return to
Question

55. Additions of H2O to Alkenes (I)
(Exercise C)
Be sure to correctly apply Markovnikov’s Rule in your mechanism. Ask the question “How can a
proton be added to the alkene in such a way that the resulting carbocation is in the more stable
location?”
Note how the acid-catalyzed mechanism begins with the consumption of the acid and ends with
its regeneration
Acid-Catalyzed Hydration
Return to
Question

56. Additions of H2O to Alkenes (I)
(Exercise D)
Each if the three products involves a rearrangement of the carbocation intermediate. The answer
below shows the rearrangement steps using green arrows for clarity.
Acid-Catalyzed Hydration
Return to
Question

57. Additions of H2O to Alkenes (II)
(Exercise A)
Acid-Catalyzed Hydration
Return to
Question
A)

58. Additions of H2O to Alkenes (II)
(Exercise B)
Acid-Catalyzed Hydration
Return to
Question
B)

59. Additions of H2O to Alkenes (II)
(Exercise C)
Acid-Catalyzed Hydration
Return to
Question
C)

60. Additions of H2O to Alkenes (II)
(Exercise D)
Acid-Catalyzed Hydration
Return to
Question
D)

61. Additions of H2O to Alkenes (II)
(Exercise E)
Acid-Catalyzed Hydration
Return to
Question
E)

62. Additions of H2O to Alkenes (II)
(Exercise F)
Acid-Catalyzed Hydration
Return to
Question
F)
(Ring Expansion Product)

63. Additions of H2O to Alkenes (III)
Oxymercuration-Demercuration
Rearrangements are not observed because no carbocation is ever
generated in the mechanism and therefore no carbocation shifts can occur.
The carbons in this case only develop partial charges and the water attacks
the more substituted location (similar to bromonium ion) that results in
the final markovnikov orientation.
Return to
Question

64. Additions of H2O to Alkenes (IV)
(Exercise A)
Oxymercuration-Demercuration
Consider both regiochemistry and stereochemistry. Remember to indicate stereoisomerism
when appropriate.
Return to
Question
A)

65. Additions of H2O to Alkenes (IV)
(Exercise B)
Oxymercuration-Demercuration
Consider both regiochemistry and stereochemistry. Remember to indicate stereoisomerism
when appropriate.
Return to
Question
B)

66. Additions of H2O to Alkenes (IV)
(Exercise C)
Oxymercuration-Demercuration
Consider both regiochemistry and stereochemistry. Remember to indicate stereoisomerism
when appropriate.
Return to
Question
C)

67. Additions of H2O to Alkenes (IV)
(Exercise D)
Oxymercuration-Demercuration
Consider both regiochemistry and stereochemistry. Remember to indicate stereoisomerism
when appropriate.
Return to
Question
D)

68. Additions of H2O to Alkenes (V)
Hydroboration-Oxidation
As successive alkyl groups are added, steric bulk increases and increasingly favors a transition
state that minimizes steric forces. The anti-markovnikov orientation is thus preferred; the more
substituted alkene carbon across from the smaller borohydride H.
Return to
Question

69. Additions of H2O to Alkenes (VI)
(Exercise A)
Hydroboration-Oxidation
Return to
Question
You should consider both regio and stereo selectivity when predicting the
products. Be mindful of any chiral products that are generated.
A)

70. Additions of H2O to Alkenes (VI)
(Exercise B)
Hydroboration-Oxidation
Return to
Question
You should consider both regio and stereo selectivity when predicting the
products. Be mindful of any chiral products that are generated.
B)

71. Additions of H2O to Alkenes (VI)
(Exercise C)
Hydroboration-Oxidation
Return to
Question
You should consider both regio and stereo selectivity when predicting the
products. Be mindful of any chiral products that are generated.
C)

72. Additions of H2O to Alkenes (VI)
(Exercise D)
Hydroboration-Oxidation
Return to
Question
You should consider both regio and stereo selectivity when predicting the
products. Be mindful of any chiral products that are generated.
D)

73. Additions of H2O to Alkenes (VI)
(Exercise E)
Hydroboration-Oxidation
Return to
Question
You should consider both regio and stereo selectivity when predicting the
products. Be mindful of any chiral products that are generated.
E)

74. Epoxidation Reactions
(Exercise A)
A)
Return to
Question

75. Epoxidation Reactions
(Exercise B)
B)
Return to
Question

76. Epoxidation Reactions
(Exercise C)
C)
Return to
Question

77. Epoxidation Reactions
(Exercise D)
D)
Return to
Question

78. Acid/Base Catalyzed Ring Openings of Epoxides (I)
(Exercise A)
Return to
Question

79. Acid/Base Catalyzed Ring Openings of Epoxides (I)
(Exercise B)
Return to
Question

80. Acid/Base Catalyzed Ring Openings of Epoxides (I)
(Exercise C)
Return to
Question

81. Acid/Base Catalyzed Ring Openings of Epoxides (I)
(Exercise D)
Return to
Question

82. Acid/Base Catalyzed Ring Openings of Epoxides (II)
(Exercise A)
Return to
Question
A)

83. Acid/Base Catalyzed Ring Openings of Epoxides (II)
(Exercise B)
Return to
Question
B)

84. Acid/Base Catalyzed Ring Openings of Epoxides (II)
(Exercise C)
Return to
Question
C)

85. Acid/Base Catalyzed Ring Openings of Epoxides (II)
(Exercise D)
Return to
Question
D)

86. A)
Oxidative Cleavage via Ozonolysis
(Example A)
Return to
Question
*NOTE* The reagents used in the second step of these reactions (Zn and DMS) are said to be
“reductive” workups for their ability to leave 1° carbons as aldehydes. However there are
other reagents (H2O2) that that convert 1° carbons to carboxylic acids and are thus termed
“oxidative” workups.
The terms “reductive” and “oxidative” in this case are relative to each other; both workups
still yield products that are more oxidized than the alkene staring material.

87. Oxidative Cleavage via Ozonolysis
(Example B)
Return to
Question
B)
*NOTE* The reagents used in the second step of these reactions (Zn and DMS) are said to be
“reductive” workups for their ability to leave 1° carbons as aldehydes. However there are
other reagents (H2O2) that that convert 1° carbons to carboxylic acids and are thus termed
“oxidative” workups.
The terms “reductive” and “oxidative” in this case are relative to each other; both workups
still yield products that are more oxidized than the alkene staring material.

88. Oxidative Cleavage via Ozonolysis
(Example C)
Return to
Question
C)
*NOTE* The reagents used in the second step of these reactions (Zn and DMS) are said to be
“reductive” workups for their ability to leave 1° carbons as aldehydes. However there are
other reagents (H2O2) that that convert 1° carbons to carboxylic acids and are thus termed
“oxidative” workups.
The terms “reductive” and “oxidative” in this case are relative to each other; both workups
still yield products that are more oxidized than the alkene staring material.

89. Oxidative Cleavage via Ozonolysis
(Example D)
Return to
Question
D)
*NOTE* The reagents used in the second step of these reactions (Zn and DMS) are said to be
“reductive” workups for their ability to leave 1° carbons as aldehydes. However there are
other reagents (H2O2) that that convert 1° carbons to carboxylic acids and are thus termed
“oxidative” workups.
The terms “reductive” and “oxidative” in this case are relative to each other; both workups
still yield products that are more oxidized than the alkene staring material.

90. Oxidative Cleavage via Ozonolysis
(Example E)
Return to
Question
E)
*NOTE* The reagents used in the second step of these reactions (Zn and DMS) are said to be
“reductive” workups for their ability to leave 1° carbons as aldehydes. However there are
other reagents (H2O2) that that convert 1° carbons to carboxylic acids and are thus termed
“oxidative” workups.
The terms “reductive” and “oxidative” in this case are relative to each other; both workups
still yield products that are more oxidized than the alkene staring material.

91. Oxidative Cleavage via Ozonolysis
(Example F)
Return to
Question
*NOTE* The reagents used in the second step of these reactions (Zn and DMS) are said to be
“reductive” workups for their ability to leave 1° carbons as aldehydes. However there are
other reagents (H2O2) that that convert 1° carbons to carboxylic acids and are thus termed
“oxidative” workups.
The terms “reductive” and “oxidative” in this case are relative to each other; both workups
still yield products that are more oxidized than the alkene staring material.
The pi-bonds within the phenyl ring are less reactive (due to aromatic properties) and are
thus resistant to ozonolysis.

92. Predict the Products (I)
(Exercise A)
Return to
Question
A)

93. Predict the Products (I)
(Exercise B)
Return to
Question
B)

94. Predict the Products (I)
(Exercise C)
Return to
Question
C)

95. Predict the Products (I)
(Exercise D)
Return to
Question
D)

96. Predict the Products (I)
(Exercise E)
Return to
Question
E)

97. Predict the Products (II)
(Exercise A)
Return to
Question
A)

98. Predict the Products (II)
(Exercise B)
Return to
Question
B)

99. Predict the Products (II)
(Exercise C)
Return to
Question
C)

100. Predict the Products (II)
(Exercise D)
Return to
Question
D)

101. Predict the Products (II)
(Exercise E)
Return to
Question
E)

102. Predict the Products (II)
(Exercise F)
Return to
Question
F)

103. Predict the Reagents
(Exercise A)
Return to
Question
A)

104. Predict the Reagents
(Exercise B)
Return to
Question
B)

105. Predict the Reagents
(Exercise C)
Return to
Question
C)

106. Predict the Reagents
(Exercise D)
Return to
Question
D)

107. Predict the Reagents
(Exercise E)
Return to
Question
E)

108. We would like to evaluate these exercises by seeing how helpful you found them.
Please click the link below to take a quick 3 minute survey:
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