Chem 242 @ Dickinson

Rearrangements

Yesterday was a rearrangement day. We spent nearly all of the class period going over the Curtius and the Hofmann rearrangements. The key to each is that a leaving group is attached to a nitrogen atom -- heat (energy) allows the compound to undergo the desired rearrangement. It is important that you understand these mechanisms, and the similarities between them.

We also touched on the Hofmann elimination. In this example, Hofmann took advantage of the ability of a nitrogen to "overalkylate" and obtain a positive charge. Such an atom is a good leaving group and with clever use of (non-nucleophilic) base an elimination reaction can take place.

Tomorrow we will finish up Chapter 24 by looking at some chemistry of aromatic amines and hopefully start Chapter 25.

posted by DCChem @ 10:51 AM