last updated Thursday, May 17, 2007

Meeting 15 (Acetyl Ferrocene)

Important Announcements:

1. The proposal is due on May 25, 2007 at 5 pm in YH 3077 E (If you have problems please see me asap!). Late proposal will not be accepted and will lead to an automatic "F"-grade for the course since you will not be allowed to carried out the project. The important references have to be attached to the proposal. The proposal has to be submitted to turnitin.com as well (same course ID as before) by 10 pm on this day, only once per group!

2. The next quiz will be administered on May 23, 2007 at 12 pm. It will cover the ferrocene, the acylation reaction and the formation of heterocycles. Make sure to come on time since you will not be allowed to take the quiz on Wednesday if you arrive late. There have been several complaints about this very disruptive and inconsiderate behavior.

3. In the lab, you will only carry out the acylation of ferrocene, but not the synthesis of ferrocene. This part will be done individually and not in groups.

Homework assignments (due May 22/23, 2007)

1. Referring to the synthesis of ferrocene, answer the following questions.

a. Why is cyclopentadiene not commercially avaible? How is it obtained in the lab? Which precautions have to be taken?

b. Rank the following compounds according to their acidity: cyclopentane, cyclohpentadiene, 1-pentene. Explain briefly.

c. Why should an iron(II) salt be used as iron source in this reaction and not an iron(III) salt?

d. A student decides to use petroleum ether as solvent for the reaction. What would he observe?

e. Why can the final product be purified by sublimation?

f. The ¹³C-NMR spectrum of ferrocene exhibits one signal at ~68 ppm. Rationalize the observation.

2. Referring to the synthesis of acetyl ferrocene, answer the following questions.

a. How is the acylium ion generated in the lab? Show pertinent chemical equation(s).

b. Why does a Friedel-Crafts acylation usually lead to mono-acylation even with "activated" arene systems?

c. Which compounds does the reaction mixture contain after the completion of the reaction?

d. A student observe a blue-greenish color of the aqueous layer during the work-up. Rationalize this observation.