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Writing Equations for Each of the Given Reagents

1. Write an equation for the reaction of 3-methyl-2-pentene with each of the following reagents:
a. hydrogen bromide
b. BH3 followed by H2O2, OH¯
c. hydrogen (Pt catalyst)
d. KMnO4, OH¯
e. bromine
f. H2O, H+

2. What reagent will react by addition to what unsaturated hydrocarbon to form each of the following compounds?



3. Which of the following reagents is an electrophile? Which is a nucleophile?
a. Br¯
b. BF3
4. Explain in your own words why the water molecule can act either as an electrophile or as a nucleophile.
5. The acid-catalyzed hydration of 1-ethylcyclopentene gives 1-ethylcyclopentanol. Write every step in the mechanism of this reaction. +
6. Draw the resonance contributors to the carbocation CH3CHCH=CHCH2CH3 does the ion have a symmetric structure? (positive sign over the first CH single bond)
7. Adding one equivalent of sulfuric acid to 2,4-hexadiene gives two products. Give the structures, and write all the steps in a reaction mechanism that explains how each product is formed.
8. Predict the product of this Diels-Alder reaction.

9. Write an equation that clearly shows the structure of the alcohol obtained from the sequential hydroboration and H2O2/OH¯ oxidation of 1-methylcyclohexene.
10. Write equations to show how 2-methyl-1-pentene could be converted to
a. 2-hydroxy-2-methylpentane
b. 1-hydroxy-2-methylpentane
11. Write equations for the following reactions:
a. 2-pentyne + H2 (1 mol, Lindlar's catalyst)
b. 1-butyne + HBr (2 mol).

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Solution Preview

See the attachment.

1. See Figure 1 for equations. Note: the reactant has E- and Z- isomers, but both would give the same products in this problem.
a. Gives Markovnikov addition
b. Gives anti-Markovnikov addition of water
c. Produces an alkane
d. Produces a diol
e. Bromination of an alkene gives a 1,2 dibromoalkane. Note: If the alkene is cyclic, only the trans dibromo product is formed.
f. Gives Markovnikov addition
2. See Figure 2.
a. Reactant is 2-butyne.
Notes on part a: The product could be cis or trans (not specified in the question). Lindlar's catalyst plus hydrogen gas (see problem 11a) will give the cis isomer. The treatment shown here ...

Solution Summary

The solution assists in writing equations for each of the given reagents.