Rules of the Day 320N

1. The anions of terminal alkynes add to aldehydes and ketones to give tetrahedral alkoxide intermediates (can be isolated). These alkoxides are protonated when the chemist opens the flask and adds acid to give alkyne alcohols. Mechanism A. Carbon-carbon bond forming! See the movie by clicking here

2. HCN is in equilibrium with H+ and CN-. CN- reacts with aldehydes and ketones to give a tetrahedral alkoxide intermediate that cannot be isolated becuase it is immediately protonated to give a cyanohydrin product. Mechanism A. Carbon-carbon bond forming! Time Capsule: Cyanohydrins are hydrolyzed in strong H3O+ to give alpha-hydroxy carboxylic acids. See the movie by clicking here

3. Wittig reactions form C=C bonds from C=O bonds through reaction of the nucleophilic ylide via the famous four-membered ring intermediate (See Pictures of the Day). This is a useful reaction because carbonyl compounds are easily made, and the ylides are made from haloalkanes, also easy to make. Unique mechanism! (See Pictures of the Day) Carbon-carbon bond forming!

4. Alkyl Wittig reagents give predominantly "Z" (cis) alkene products, while Wittig reagents with a carbonyl adjacent to the negative charge give predominantly "E" (trans) products.

5. Aldehydes and ketones can be reduced by H2/Pd to give alcohols. (Watch for racemic mixtures!) Note that this method will also reduce any carbon-carbon double or triple bonds that happen to be in the molecule.

Homework:

Read: Sections 16.7, 16.8 in the ebook textbook. This text is part of the Longhorn Textbook access program.

If you are new to my class, you might want to take my old CH320M/CH328M final (from 12-10-22). This will give you a calibration regarding your preparation for this class. Click here for a copy of the old CH320M/CH328M final.My class average on this exam was right around 79% on this final. (GREAT JOB shout out to my Fall of 2024 class by the way!!!) Click here for a copy of the same final exam with answers.

Take the Daily Quiz 4 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.

Start working on the Gradescope Homework Problem Set 2, due at 10 PM on Wednesday, Juanuary 29. Click here to access the Homework Problem Set 2.

There is also an Aktiv Learning Homework Problem Set 2 as well (there was no Aktiv Learning homework Problem Set 1) If you already have an Aktiv Learning account, click here to get the Aktiv Homework Problem set 2 (there was no Aktiv Homework Problem set 1)

Click here if you need to set up an Aktiv Learning account. This takes you to the Modules page of Canvas. Then Click on "Active Sign Up (Click this one if you are creating an account)" Warning, it costs $36 to sign up for Aktiv Learning but previous students found this to be worth the money (although I am always open to that conversation). If you need help getting this to work, click here.

Homeworks will be worth 10% of your final grade (20% from the Aktiv Learning and 80% from the Gradescope portions of the homework).

Click here for directions on how to use Gradescope