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 second quiz will be administered on Thursday, October 9, 2008 at 11 am covering the resolution and the ligand synthesis. Bring a ruler, non-graphing calculator and pen with you. Please make sure that you arrive on time (this also applies to the morning sections!). 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!!!

Questions

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

a. What is the function of the hydrobromic acid in the reaction?

b. How is the temperature controlled during the reaction? Which temperature is desirable here?

c. The reaction is monitored using TLC. Which samples should be spotted here? What is he looking for here?

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

e. A student extracts the mixture from d. with hexane. Rationalize this choice.

f. Can dichloromethane be used to recrystallize the crude aldehyde? Explain.

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

a. When the diamine is added to the acid solution, a small amount of precipitate is initially observed that dissolves upon further addition of the diamine. Explain.

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

c. The accepted optical rotation value for the product is [a]_D²⁰= +12.5^o. A student observes a specific optical rotation for his sample of [a]= +8.2^o. Determine the optical purity of the sample. Which impact does this result haves for the project overall?

d. What is the basis of the resolution of the enantiomers/diastereomers of the diamine?