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

1. In most cases only one enantiomers is useful for a biological process. Explain briefly why.

2. In which of the following properties are enantiomers identical?

a. Boiling point
b. IR spectrum
e. 13C-NMR spectrum in CDCl3
e. optical rotation

3. How can asymmetric induction be introduced to an achiral substrate?

4. Suggest a procedure to resolve a racemic mixture of 2-pentanol.

5. Why is it important that you add the 30% hydrogen peroxide solution slowly to the cerium solution?

6. What is the advantage of using Ce(OH)₃(OOH) for the oxidation of the alcohol over conventional reagents for the oxidation?

7. Why is it important to cool down a solution slowly during recrystallization?

8. A student isolated a compound from a natural source. The observed rotation a of a 0.5 g sample of cholesterol in 30 mL of methanol solution contained in a 5 cm polarimeter tube is -2.5^o. Calculate the specific rotation [a]_D²⁰.

9. A student isolated Jacobsen ligand from his reaction. He dissolved 0.5 g in 10 mL of dichloromethane and places the solution in a 1 dm-cell. The observed value is 15.5^o. Calculcate the optical purity for his sample assuming that the specific rotation is 315^o.