Click here for a copy of my lecture notes from today's lecture

Click here for a copy of the handout used in class today

Featured Golden Rules of Chemistry: Nothing today

1. Carbocation intermediates can rearrange if migration of an H atom or less often a methyl group will create a more stable carbocation. This is relatively rare, but can occur in certain situations. This is not a new effect, it is simply hyperconjugation taken to the extreme.

2. Alkenes react with X2 to give vicinal dihalides via a three-membered ring halonium ion intermediate. Attack from the face of the halonium ion intermediate opposite to the halogen atom leads to anti stereochemistry of addition leading to trans products. Watch the stereochemistry here! Halonium ions do not rearrange.

3. Anti stereochemistry means that the atoms add to either side of a C=C double bond, syn means they add to the same side, and mixed means they add both syn and anti in the same reaction.

4. Many reaction mechanism intermediates and products are chiral and formed as racemic mixtures. To avoid having to write too many structures, for mechanism questions, you will only need to draw one of the stereoisomers formed as an intermediate or product but you will have to LABEL ALL CHIRAL CENTERS WITH AN ASTERISK (*) AND WRITE "RACEMIC" EVERY PLACE IT IS TRUE.

5. Alkenes react with X2 in the presence of water to give halohydrins. Holonium ion intermediates again so anti adition leading to trans products. Regiochemistry is Markovinikov (OH ends up on more substituted carbon atom) because of extra charge on the more substituted carbon atom of the halonium ion intermediate.

6. Of the intermediates we have seen or will see, only carbocations rearrange, all other intermediates such as the halonium ions do not.

HOMEWORK:

If you have not already, you must Watch the Terpene video. You are responsible for this information for the next midterm! Last time we will mention it!

Read: Sections 6.5 and 6.6 in the eBook.

Take the Daily Quiz 12 before 10 PM tomorrow. Click here to access the quiz. These quizzes are designed to review the important material from today's lecture.

Keep Working on Homework Problem Set 6, due at 10 PM on Wednesday, October 15.

Click here to go to the Aktive Homework Problem Set 6

Click here to get a copy of the Gradescope Homework Problem Set 6