Chem 334 - Fall 2001
Organic Chemistry I
Dr. Carl C. Wamser

EXAM 2

1. (20 points) Write complete names for each of the following, including stereochemistry if it is specifically shown:

a)

b)

c)

d)

2. (15 points) Arrange the following sets of compounds in order with respect to the property indicated.
Write "MOST" and "LEAST" under the compounds with the highest and lowest values of the property.

a) stability

b) stability

c) rate of dehydration

d) rate of bromine addition

e) rate of SN2 substitution by HBr

3. (15 points) Complete each of the following reactions by adding the missing part - either the starting compound, the necessary reagents and conditions, or the final major product. Show stereochemistry if it would be specific.

a)

b)

c)

d)

e)

4. (15 points) Heats of combustion for four isomers are indicated below.
Arrange the four compounds in order of stability.

Heats of combustion

cyclobutane 2721 kJ/mol
1-butene 2717 kJ/mol
cis-2-butene 2710 kJ/mol
trans-2-butene 2706 kJ/mol

The heat of hydrogenation for trans-2-butene is 115 kJ/mol. Calculate what the other three values should be.

Heats of hydrogenation

cyclobutane
1-butene
cis-2-butene
trans-2-butene 115 kJ/mol

Using C4H8 to represent any of the four isomers, write the balanced reaction that corresponds to the heat of combustion.

Using C4H8 to represent any of the four isomers, write the balanced reaction that corresponds to the heat of hydrogenation.

Heating cyclobutane can lead to a ring opening to form 1-butene.
Calculate the expected delta H for this reaction.
Is it exothermic or endothermic?

5. (10 points) Free radical halogenation of ethylcyclopropane can lead to five possible monochlorination products.
Write structures for all of them.

6. (10 points) Complete the following synthetic sequence by adding the missing parts.

Elimination products may also occur in this reaction. Show the structure of any elimination products expected.