EXAM 3

CHEMISTRY 220a

Friday, November 8, 2002

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

There is a Periodic Table on the last page of the exam.

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 (20 pts) ______

2. Synthesis (20 pts) ______

3. Reactions (30 pts) ______

4. Potpourri (30 pts) ______

_______________________________

Total (100 pts)

1. Structure: (20 pts.) Compound A (C₉H₁₄) reacts with two moles of H₂ in the presence of Pd or Pt to form B. Compound B is found to be not identical with 1-cyclobutylpentane. Ozonolysis of A and subsequent reduction with dimethyl sulfide affords keto dialdehyde D and compound E. What are the structures A-E? Explain and illustrate.

2. Synthesis: (20 pts.) A chemist requires a sample of racemic 4,5-octanediol (C₈H₁₈O₂). She designs and executes a synthesis of the diol using acetylene (C₂H₂) and propene (C₃H₆) as her sources of carbon. All other reagents were available to her. Show how she may have accomplished her goal.

3. Reactions: (30 pts.) In each of the following chemical transformations, provide the reaction conditions or the products. Several steps may be required. Pay attention to stereochemistry.

4. Potpourri: (30 pts.) Circle the best answer(s) in each of the following.

a) The reactions that are conducted in the presence of a catalytic reagent.

Hg⁺⁺ hydration of acetylenes dihydroxylation with OsO₄/H₂O₂

anti-Markovnikov addition of Lindlar reduction

HBr to alkenes

hydroboration

b) Racemates are expected in the reaction of (Z)-5-decene with

Br₂ Br₂/H₂O peracid OsO₄/H₂O₂ CH₂I₂/Zn(Cu)

c) The structure(s) that represent the correct stereochemistry from the hydroboration of (E)-3-methyl-2-pentene.

d) The compound(s) in violation of Bredt’s Rule

e) The compound(s) with the smallest heat of hydrogenation

Work Sheets
Work Sheets
Periodic Table