Chemistry CHEM S-20ab Lecture Notes - Lecture 5: Hydrogen Peroxide, Bromine, Ozonolysis
30 Apr 2018
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Department
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Professor
Chemistry E-2a: Lecture 4 October 16, 2008
6
The Structure of the Bromonium Ion
• Explain why only one product is observed in the following reaction:
Br
2
H
2
O
HO
Br
• Is this observation consistent with Markovnikov’s Rule? Why or why not?
• Given all that you know about the addition of Br2 to alkenes, predict which of the four
products shown below would be the main product observed in the addition of bromine to
1-methylcyclohexene in the presence of water:
Br
2
H
2
O
Br
OH
Br OH
Br
OH
OH Br
A B C D
Reading: Section 5.1
Chemistry S-20ab
Week 1
67
Chemistry E-2a: Lecture 4 October 16, 2008
7
Conversions of Alkenes into Alcohols:
Review of Alkene Hydration
• You already know one method for accomplishing the following transformation. What is
that method? What is its mechanism?
OH
• Now suppose you want to carry out the following transformation. Can you use the same
method as you did above? Why or why not?
OH
• What kinds of reactions might we want to avoid when carrying out organic synthesis in
the laboratory?
Reading: Section 4.9
Chemistry S-20ab
Week 1
68
Document Summary
Explain why only one product is observed in the following reaction: Given all that you know about the addition of br2 to alkenes, predict which of the four products shown below would be the main product observed in the addition of bromine to. You already know one method for accomplishing the following transformation. Now suppose you want to carry out the following transformation. We can convert an alkene into an alcohol with the following two-step process: Let"s take a close look at the mechanisms of the following reactions. We can accomplish the anti-markovnikov addition of water to an alkene with the following two-step process: Let"s take a closer look at the first step of this reaction: Now, let"s look at the mechanism of the second step of the hydroboration-oxidation sequence: Explain why hydroboration-oxidation of 1-methylcyclohexene gives only the product shown below: bh3 , thf, h2o2 , oh .
