Spring 1995 Exam Questions relevant to Spring 1997 Exam 2
© Kenn Harding, Texas A&M University

1. (2 pts)

Draw the structure corresponding to the IUPAC name below.

a) (3E, 5Z)-3-ethyl-6-methyl-1,3,5-octatriene

2. (6 pts)

Label the following structures as (E) or (Z) isomers:

a) b)

3. (4 pts)

Calculate the number of rings plus double bonds (degrees of unsaturation) in mescaline (C11H17NO3), a hallucinogen isolated from peyote cactus.

4. (12 pts)

Predict the major products for the following reactions. If more than one product is expected in significant amounts, draw all of them.

a)

b)

c)

d)

5. (18 pts) Write the major products expected for the following reactions. Show the expected stereochemistry.

a)

b)

c)

d)

e)

f)

6. (9 pts)

Consider the following alkenes:

a) Which alkene is the most stable? _______________

b) Which alkene will have the highest heat of hydrogenation? ______________

c) Which alkene(s) will give a single product upon reaction with HBr and peroxides? _________________

7. (20 pts)

Draw the 10 isomers (including stereoisomers) of C4H7Cl that are alkenes.

8. (15 pts)

Give the best reagent combination for carrying out each of the transformations shown below. Write the answers over the arrows.

a)

b)

c)

d)

e)

9. (9 pts)

Draw the structure of the starting material that would produce the product shown as the major product.

a)

b)

c)

10. (6 pts)

a) Which of the following reactions result in syn addition to alkenes? _____________

1) hydrogenation
2) hydrobromination
3) hydration
4) hydroboration

b) Which of the following reactions involve carbocation intermediates? ________________

1) hydrogenation
2) hydroxylation
3) hydration
4) hydroboration

c) Which of the following react with alkenes by a free radical mechanism? ______________

1) HBr/peroxides
2) BH3
3) Hg(OAc)2
4) OsO4

16. (10 pts)

Write a complete stepwise mechanism for the following reaction. Show all intermediate structures and show all electron flow using the curved arrow convention. Show stereochemistry clearly at all steps.

17. (10 pts)

Show all the reagents and intermediates necessary to carry out the following conversion. More than one step is required. You may use any needed reagents and organic halides of up to four carbons.

15. Consider the following reaction:

a) Label the electrophile and the nucleophile (4 pts)

b) This is an example of which class of reaction? (Circle the correct answer) (3 pts)

- polar addition reaction

- radical elimination reaction

- polar substitution reaction

- rearrangement reaction

c) Although this reaction is slow, the products are favored at equilibrium. Draw a reaction energy diagram for the above reaction. (Label the transition state, the activation energy, and the DGo on the diagram.) (6 pts)

16. Consider the following reaction energy diagram:

a) Label the DGo for the reaction. Is it positive or negative? . (4 pts)

b) How many steps are involved in the reaction? . Which step is faster? (4 pts)

c) Label the transition states and the activation energies for each step. (6 pts)