Download CH 420, Spring 2015 Name ___________________________ CH 18 practice problems

CH 420, Spring 2015
CH 18 practice problems
Name ___________________________
1) Draw the products of the following ester reduction. Consider the mechanism of the reaction and
relative reactivity of carbonyl compounds towards nucleophiles.
2) Tert-butyloxycarbonyl (Boc) is a common protecting group for amines. Removal of this group is
accomplished by treatment with acid. Outline the mechanism of the initial steps of Boc cleavage,
noting that this reaction works only for tert-butyl carbamate – not methyl, ethyl, propyl, etc.
3) Determine the product obtained by treatment of the following chiral alcohol with base. Clearly
indicate stereochemistry.
What is the mechanism in the above reaction?
4) Indicate the product with its appropriate regio- and stereochemistry. Note the reaction conditions.
5) Thiols can be converted to disulfides by treatment with iodine. In this transformation, iodine is a(n):
a.
b.
c.
d.
e.
f.
Acid
Base
Nucleophile
Electrophile
Oxidizing agent
Reducing agent
6) Complete the following scheme. The pKa of thiophenol is ca. 7.
Are thiols more or less nucleophilic than their corresponding alcohols?
Are sulfides (thioethers) more or less prone to oxidation than the corresponding ether?
7) Rank the following compounds according to their relative acidity: cyclohexanol, phenol, pmethoxyphenol, p-nitrophenol.
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Most acidic
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________________
Least acidic