BA
I II III IV
VVI VII VIII
Cl
Br
Br
OH
OH
+ En
OH
A) B = I and A = VI
B) B = VI and A = I
C) B = V and A = II
D) B = IV and A = VII
E) B = I and A = III
F) B = VIII and A = V
68. Show that you understand the concept of retrosynthetic analysis by working
backwards two steps in the synthesis below. Identify possible combinations of A
and B that can lead to the alkene (C):
BA
Br
III III
V VI VII
Br HO
A) B = I and A = V
B) B = II and A = VII
C) B = III and A = I
D) B = I and A = VII
E) B = II and A = VI
F) B = III and A = II
69. Devise a method of converting methylcyclobutane into cyclopentene.
??
70. Devise a method of converting ethylene into PVC (polyvinyl chloride).
71. Devise a method of converting acetylene into the polymer shown below.
Cl
n
Chapter 12
Topic: Retrosynthetic Analysis
Section: 12.5
Difficulty Level: Medium
72. Devise a method of converting trans-2-methyl-3-hexene into 5-methylhexanal.
73. Devise a method of converting trans-2-methyl-3-hexene into 4-methylpentanoic
acid.
74. Which of the following effectively produces 4,4-dimethyl-2-pentyne?
A) Br
+ NaCCCH3
B) + CH3Br
C)
Br Br
+ 2 NaNH2
D) Br
+ 1 NaNH2
75. Devise an efficient synthesis of the diol shown below starting with 1,1,3,3-
tetramethyl-2-ethylcyclohexane.
OH
OH
+ En
76. Devise an efficient synthesis of the diol shown below starting with 1,1,3,3-
tetramethyl-2-ethylcyclohexane.
OH
OH
+ En
Chapter 12
Topic: Retrosynthetic Analysis
Section: 12.5
Difficulty Level: Difficult
77. Devise an efficient synthesis of the compound shown below starting with 4-
methyl-2-pentanol.
O
O
OH
78. To add one carbon directly to the end of a primary alkyl bromide, one could:
A) substitute bromide with acetylide, then cleave the triple bond.
B) substitute bromide with acetylide, then reduce the alkyne to an alkene.
C) substitute bromide with methoxide.
D) eliminate hydrogen bromide to produce an alkene.
79. To remove one carbon from the end of a primary alkyl bromide, one could:
A) substitute bromide with acetylide, then cleave the triple bond.
B) substitute bromide with acetylide, then reduce the alkyne to an alkene.
C) substitute bromide with methoxide.
D) eliminate hydrogen bromide to produce an alkene, then cleave the
double bond.
80. Devise a method to complete the following synthesis.
Br
OH
+
OH
??
81. Devise a method to complete the following synthesis.
O
acetylene
82. Devise a method to complete the following synthesis.
O
acetylene
+ En
83. Devise a method to complete the following synthesis.
N N
84. Devise a method to prepare 1,7-heptanediol from propene.
85. Devise a method to prepare 1,3-dibromopropanol from propene.
86. Devise a method to prepare 3-bromo-1-propanol from propene.
87. Devise a method to complete the following synthesis.
N
88. Devise a synthesis to lengthen the legs of “Ralph” as requested below.
