ATTN: answers to the below questions are due at the start of your second meeting; these answers should be part of your pre-lab write-up. There will be a quiz in lecture on Thursday 10/7/2004. Please make sure that you arrive on time since the quiz will be administered in the beginning of the lecture.

1. Referring to step 2, answer the following questions:

a. What is the function of the sodium hydroxide in this step? Show pertinent equations.

b. How much solvent would be appropriate to use for the extraction part of the procedure? Rationalize your choice.

c. Why is dichloromethane used as a extraction solvent here and not hexane?

d. How can the removal of the solvent be sped up while overheating of the crude product is avoided?

e. Why is it necessary to use capillary tubes for the spotting of the TLC plates?

f. Sketch the TLC plate with your product in lane 1, the starting material in lane 2 and the aldehyde in lane 3.

2. Referring to step 3, answer the following questions:

a. Show a balanced equation for the reaction.

b. What is the function of the conc. HBr?

c. Why is it imperative that the reaction temperature does not significantly raise above 120 ^oC?

d. Which evidence do the authors provide for their proposed mechanism?

3. Draw a transition state for the reduction of acetophenone with with R-BINAL. Which enantiomer of the alcohol is obtained after hydrolysis of this intermediate?

4. Why is it desirable to have both enantiomers of a chiral auxiliary?