Rules of the Day CH320M/328M

Featured Golden Rules of Chemistry: Nothing today

1. For each reaction of an alkene we have covered you need to remember to call a NIRRS:

Nature of the reaction; what is the starting material/product? (i.e. alkene converted to an alcohol)

Intermediate (or "Important transition state" if applicable) of the reaction, the key to the mechanism (carbocation, halonium ion, etc.)

Reagents Learn the exact way to designate the reagents for each reaction

Regiochemistry What is the regiochemistry of addition? (Markovnikov, non-Markovinikov, etc.)

Stereochemistry of addition (anti, syn or mixed)

2. When studying for the exam, remember this material is very different then the first midterm material. You CAN do this. I suggest you follow these steps before looking through old exams: 1) Read each Rule of the Day so you can identify those things you are not familiar with. 2) Binge-watch the lectures recordings, skipping the things you undersrtand and spending time watching the things you do not yet understand (last year's class used this study method and they did great!) 3) Consult the Missed the Wave topics to see if you can get help from those recordings 4) Ask questions at office hours and the Review Session on Tuesday night 5) Start working through the old exams.

3. Alkenes react with 1) BH3, 2) H2O2/HO- to give an alcohol. The reaction involves a four-membered ring transition state in which the H ends up on the more highly substituted carbon, largely for steric reasons, so the reaction shows non-Markovnikov regiochemistry. Note the BH3 reacts three times, so one BH3 molecule reacts with three alkenes. The last step does not mix the stereochemistry, so overall it is syn stereochemistry.

4. An oxidation reaction involves a net loss of electrons and replaces C-H bonds with C-O bonds or pi bonds. A reduction reaction involves a net gain of electrons and replaces C-O or pi bonds with C-H bonds.

5. Alkenes are oxidized with 1) OsO4, 2) NaHSO3/H2O to give vicinal diols (glycols) . You are not responsible for Ozzy Osbourne mechanism because it involves metal species, but you should know about the key cyclic osmate intermediate because this explains the syn addition stereochemistry. Regiochemistry is not important because OH adds to both atoms.

Nothing after this is going to be covered on the 2nd midterm.

6. Alkenes react with O3 (ozone) followed by (CH3)2S to give C=C bond cleavage and two new C=O bonds. You are not responsible for entire mechanism but you should be familiar with malozonide and ozonide intermediates. Regiochemistry and stereochemistry do not apply. THIS IS THE ONLY WAY TO BREAK CARBON-CARBON BONDS that you will see this semester so this is a very important chemical reaction for synthesis!

HOMEWORK:

Read: Study for the exam next week.

Take the Daily Quiz 14 before 10 PM tomorrow. Click here to access the quiz. These quizzes are designed to review the important material from today's lecture. Together, they will count as 3% of your final grade.

Finish working on the Homework Problem Set 7, due at 10 PM on Tuesday, October 22. Click here to access the Homework Problem Set 7. Note there are Aktiv Learning and Gradescope Questions, and you MUST DO BOTH. Collectively, homeworks count for 10% of your final course grade. The Aktiv Learning homework provides multiple attempts and provides feedback. It is intended to help you prepare for the Gradescope Questions, so we recommend you do the Aktiv Learning questions first.

There is also a 2nd Midterm problem set. You will not turn this in, but it will help you prepare. Click here for the Problems and click here for the Answers.