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

The first quiz will be administered on Monday, October 9, 2006 at 12 pm covering step 2, step 3 and the theoretical aspects of asymmetric synthesis. Please make sure to come on time.

Questions

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

a. What is the function of the dimethyl sulfoxide in this reaction?

b. Why does the reaction mixture have to be heated to 105 ^oC? How is this accomplished in the lab?

c. How does the experimenter know if the reaction is completed?

d. Hexane used as solvent for extraction in this experiment. Rationalize this choice.

e. Which purpose does the extraction with sodium chloride solution serve?

f. The crude product is recrystallized from hot methanol. Rationalize this choice. Which precautions should be taken here?

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

a. Why should the diamine be added slowly to the tartaric acid solution?

b. During the course of the reaction a precipitate forms initially which redissolves upon further addition of the diamine. Rationalize this observation.

c. Which purpose does the addition of the acetic acid serve?

d. What is the maximum yield (in g) based on the amounts given in the reader?

e. The accepted optical rotation value for the product is a= +12.5^o. A student observes an specific optical rotation for his sample of a= +12.0^o. Rationalize the difference.