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. In some cases the solution starts to turn brown immediately after the Mn(OAc)₂ was added, in other cases only after the introduction of air. Explain briefly why and show pertinent equations.

b. The literature indicates that the reaction takes anywhere between 30-60 minutes to complete the reaction? How can the reaction time be optimized?

c. What is the function of the LiCl in the experiment?

d. Which changes are observed in the IR spectrum going from the ligand to the catalyst?

e. A student plans to acquire the UV-Vis spectrum for the catalyst in the range from 200-700 nm. Determine the appropriate concentration.

f. Why is heptane added during the workup?

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

a. Which function do the tert.-butyl groups have in the catalyst?

b. Why are only the (R,R) and the (S,S)-form of the catalyst used in asymmetric synthesis?

c. To a certain degree the catalyst works similar compared to cytochrome P₄₅₀. Explain briefly.

3. Why are transition metal complexes like Jacobsen's catalyst often used in catalysis? (Hint: Would the corresponding Mg-compound also be catalytically active?)