ATTN: answers to the below questions are due at the start of your second lab period; these answers should be part of your pre-lab write-up.

Announcements

1. The first quiz will be administered on Monday, April 9, 2007 at 12 pm covering step 2, step 3 and the theoretical aspects of asymmetric synthesis. Bring a ruler, non-graphing calculator and pen with you. Make sure to come on time.

Questions

1. Referring to the oxidation of the benzylic alcohol (step 3), answer the following questions:

a. How long is the reaction expected to take under normal circumstances? What does this mean logistically speaking?

b. The reaction is monitored using TLC. What should the student spot on the plate?

c. Why is it imperative to control the temperature in this reaction well (100 +/- 5^oC)?

d. After the reaction is terminated, the solution is poured into water? Explain briefly why.

e. Hexane is used as solvent for extraction in this experiment. Which advantage does this solvent have compared to dichloromethane?

f. Assuming a student wants to use the same reaction to oxidize p-nitrobenzylalcohol. What would he observe?

2. Referring to the resolution of 1,2-diaminocyclohexane (step 1), answer the following questions.

a. The separation of the different enantiomers is based on the different solubilities of the tartrate salts? Which factors influence their solubility?

b. What is glacial acetic acid? Why is it used in this reaction?

c. What is the maximum yield (in g) based on the amounts and chemicals given in the reader? Show all calculations.

d. The accepted optical rotation value for the product of step 1 is a= +12.5^o. A student observes a specific optical rotation for his sample of a= +11.8^o (corrected for concentration). Rationalize the difference and explain which impact each of it has for the project overall.

e. In addition to polarimetry, gas chromatography can be used to evaluate the optical purity. Explain briefly how the student has to set up the experiment.