Rules of the Day 320N

Click here for a copy of the lectures notes I wrote in class

Click here for a copy of the handouts I used in class today

1. Substituents already on the ring influence reactivity and orientation by interacting with the partial positive charges of the arenium ion intermediate. The groups are analyzed on the basis of pi donation (resonance of lone pairs on atoms attached to ring donated into aromatic pi system), hyperconjugation (alkyl groups donate electron density into aromatic pi system), and inductive effects (electron withdrawing groups remove electron density).

2. Activating ortho,para directing groups operate by stabilizing an adjacent positive charge through resonance (for groups with lone pairs on atoms attached to the ring) or hyperconjugation (for alkyl groups). These are sometimes called electron releasing groups. THE GOOD

3. Deactivating, meta directing groups operate by destabilizing an adjacent positive charge through an inductive effect. These are sometimes called electron withdrawing groups and they usually have pi bonds to heteroatoms on the atoms attached to the ring or a highly positively-charged atom attached to the ring.THE BAD

4. Halogens are deactivators due to inductive effects, but ortho,para directors due to a resonance effect. THE UGLY

5. If there are two groups on the ring, and they predict different products, then just like in the movie, Good beats Ugly or Bad, and Ugly beats Bad. Bad always loses. Because of steric hindrance, electrophiles never add between meta substituents.

6. H2 and Ni will convert a -NO2 group into a -NH2 group on an aromatic ring.

7. GOOD groups lower the energy of arenium ion intermediates complared to benzene, UGLY and especially BAD groups raise the energy of arenium ion intermediates compared to benzene. Rings with GOOD groups react faster than benzene, while rings with UGLY and especially BAD groups react slower than benzene.

Homework:

Read: Sections 23.1 - 23.6, 23.8 in the ebook textbook. This text is part of the Longhorn Textbook access program.

Take the Daily Quiz 19 before 10 PM tomorrow. Click here to access the quiz.

Start working on the Homework Problem Set 10, due at 10 PM on Monday, April 22. Click here to access the Homework Problem Set 8. This IS AN IMPORTANT ONE!! We will be grade it for completion only. There is no Aktiv learning portion of this homework, just Gradescope.