EXAM 4

CHEMISTRY 220a

Friday, December 3, 2004

NAME (print): ___________________________________________________

TA:_____________________ Day:_________________ Time:__________

Take a few moments to look over the exam. Answer each question on the exam paper.

Important clues, points, and structures are in bold.

Do all preliminary drawing or computations on the work sheets at the end of the exam. The work sheets will not be graded

The exam is 55 minutes.

STOP writing and hand in your exam when you are asked to do so.

Remember: Neatness is to your advantage.

1. Structure (25 pts) ______

2. Synthesis (25 pts) ______

3. Reactions (25 pts) Do 4 of 5. ______

4. Potpourri (25 pts) Do 4 of 5. ______

_______________________________

Total (100 pts)

1. Structure: (25 pts.) When compound A (C₉H₁₈O₂) is treated with two equivalents of Grignard reagent B, two alcohols are isolated: 3-pentanol C and 2-methyl-3-ethyl-3-pentanol (D). When A is treated with excess LiAlH₄, alcohol C is formed along with the primary alcohol, isobutyl alcohol (E). What are the structures A-E? Explain and illustrate.

2. Synthesis: (25 pts.) A chemist requires a sample of 2-octanone. Unfortunately, it is the weekend and the stockroom is closed. She finds in the laboratory the following organic compounds: 1-butanol (n-butyl alcohol), methanol, and ethylene. She designs a synthesis of 1 using these three building blocks. She discovers that the required reagents are in the lab. Illustrate her plan, or your’s.

3. Reactions: (25 pts.) Provide the reaction conditions in 4 of 5 of the following chemical transformations. Several steps may be required. If you do all five problems, cross out the one you do not want graded.

4. Potpourri: (25 pts.) Complete 4 of 5 of the following. If you do all five problems, cross out the one you do not want graded.

a) Circle the compound(s) that are the most highly oxidized.

b) Circle the compounds that react with Grignard reagents.

cholesterol limonene methyl salicylate benzaldehyde THF

c) Circle the “alcohol” with the lowest pKa value.

Ethanol F₃CCH₂OH PhOH ClCH₂CH₂OH methanol

d) Circle the major hydroboration product derived from a-pinene (boxed).

e) Circle the chemical reaction(s) that involve a 4-electron change in oxidation level.

Work Sheets
Work Sheets
Work Sheets