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 10-26-2007 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 Monday, October 15, 2007 at 10 am covering the resolution step and the ligand synthesis. Please make sure that you show up on time. Otherwise you will not be allowed to take the quiz.

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. Why is the ligand suspension refluxed before the Mn(OAc)₂ is added?

b. Upon addition of Mn(OAc)₂ to the ligand suspension, the color of the reaction mixture already turns brown in some cases. Rationalize this observation.

c. Why is the reaction monitored with TLC? What is used as mobile phase?

d. Why is heptane added to the catalyst solution?

e. In which way are the C=N stretching frequencies in the ligand and the catalyst different? How can one rationalize this difference?

2. Referring to the use of metals in organic synthesis, answer the following questions.

a. Why are many metals used in catalytic cycles of redox reactions are transition metals?

b. Many transition metal halides are Lewis acids. In which way is this useful to synthetic chemists. Give two examples.

c. In which way is cobalamin important to the human body?