Click here for a copy of the mechanism sheet used in lecture today.
Click here for the base equivalents handout from today's class.
Rules of the Day 4-11-08
1. The 36 kcal/mol extra stability (unreactivity) of aromatic species derives from putting all the pi electrons in low energy molecular orbitals that extend over the sp2 hybridized ring atoms. These molecular orbitals involve overlap (in phase and out of phase) of the 2p orbitals on the sp2 hybridized ring atoms.
2. Aromaticity stabilizes ions and atoms in molecules exist in hybridizaiton states that maximize aromatocity. The lone pair on a ring atom will be in a 2p orbital if that leads to aromaticity. This explains why pyridine is muchmore basic than pyrrole. You will need to understand this before the next test.
3. Fused benzenoid compounds are aromatic no matter how many pi electrons they have.
4. You must learn many common names (pg. 818) and how to use ortho, para, and meta.
5. Knowing when to use phenyl vs. benzyl can be tricky!
Homework: Continue working on homework Set 9. Click here to download a copy. Read 22.1-22.2 Problems: 21.35, 21.38, 21.47, 21.49 (great problem here!, 21.54 (great practice, 22.1-22.3)
