1. General

Review the following topics: extraction, recrystallization, organometallic chemistry

2. Experiment

a. Safety

1.  4-Iodophenol and 4-bromophenol are corrosive and an irritant. Phenylboronic acid (PhB(OH)₂) is hygroscopic.

2. Methanol is toxic and flammable.

b. Experiment

It is important that the reaction mixture is properly refluxed because the reagents do not dissolve well in cold water.

The catalyst is provided by lab support in a small vial. Please do not waste it because it is fairly expensive.

The reaction time have to adjusted according to the phenol being used. Since the bromophenol is less reactive than the iodophenol, the reaction employing the bromophenol requires a longer reaction time (45 min vs. 30 min).

The addition of the hydrochloric acid has to be done careful because the carbon dioxide is formed in large quantities. This step should be performed in a large beaker.

The crude product is recrystallized from a methanol:water (~1:1).

The catalyst is removed by filtration and disposed in a separate container that is provided by lab support.

3. Things to think about

a. Why are aryl fluorides are considered poor substrates for the Suzuki coupling?

b. What is the rate-determining step in the reaction?

c. Why is palladium used in the reaction and not magnesium?