Announcements

1. Make sure that you make progress on your formal report as well in terms of literature search and writing the parts that you completed already in the lab. The draft version of paper is due on 2-2-2007 at 5 pm. The draft version is worth 15 points, the final paper 45 points. For more information what the draft is supposed to contain see here. Late submission will receive less credit. The more of your work you submit here, the more feedback you will get, which will beneficial for the final version. We will try to return the reports by Monday.

2. The next quiz will be administered on Tuesday, January 23, 2007 at 12 pm covering the resolution step and the ligand synthesis. Please make sure that you show up on time.

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. Referring to the synthesis and characterization of the Jacobsen catalyst, answer the following questions.

a. After adding Mn(OAc)₂ to the ligand suspension, the reaction mixture is stirred for some time. In many cases the color remains yellow at this point, in some cases the mixture turns brown already. Rationalize this observation.

b. The progress of the reaction is monitored by TLC. Which solvent should be used here? Sketch a plate showing an incomplete reaction.

c. After drying the solution, heptane is added to the organic layer and then the volume of the mixture reduced. As soon as a precipitate appears, the student stops the evaporation of the solvent and places the mixture in an ice-bath. In the end he only isolates a relative small quantity of the catalyst. Explain.

d. A student plans to acquire the UV-Vis spectrum for the catalyst in the range from 200-700 nm. Determine the appropriate concentration. Which solvent and which cuvette should be used?

2. Referring to the design of the catalyst, anser the following questions.

a. In which way are the cytochrome P 450 and the Jacobsen catalyst similar?

b. What is the function of the tert.-butyl groups in the catalyst?

c. What is the function of the cyclohexane part in the molecule?