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 Tuesday, January 15, 2008 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. Please make sure that you arrive on time. Late arrivals will not be allowed into the class room since they disturb the rest of the class!! This also means that you will not be allowed to take the quiz!!!

2. The second workshop (Monday, 1/14/2008, 5-5:50 pm, CS 24) will cover problem solving in infrared spectroscopy. Please make sure to print out the IR handout from the web site.

Questions

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

a. In which way does the presence of the hydroxy group on the ring influence the reactivity of the benzylic alcohol? Explain briefly.

b. Why should the reaction be carried out under the hood?

c. The reaction is monitored using TLC. Which solvent is used to dissolve the samples? What is used as eluent?

d. After the reaction is completed, the mixture is poured into water. Rationalize this step.

e. Why is hexane is used as solvent for extraction in this experiment and not dichloromethane?

f. Why is methanol used to recrystallize the crude product? Which precaution(s) should be taken here?

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

a. Why is the resolution step necessary?

b. In the beginning of the reaction a precipitate is observed that dissolves on further addition of the amine, and reappears upon addition of glacial acetic acid. Explain.

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= +11.0^o (corrected for concentration). Detemine the optical purity and rationalize the result. Which impact does this result haves for the project overall?

e. Suggest two alternative methods (other than optical rotation) to identify the optical purity of the isolated tartrate salt.

3. When designing an asymmetric synthesis reaction, what is the experimenter looking for in terms of

a. the products

b. the activation energy