Rules of the Day
2-29-2024
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
Featured Golden Rule of Chemistry: 10. A reaction mechanism describes the sequence of steps occurring during a reaction.10
1. Esters react with Grignard reagents twice to give tertiary alcohols. The reaction occurs through Mechanism B followed by Mechanism A, with a ketone produced inbetween.
2. Esters react with LiAlH4 then H2O to give two alcohol molecules through a mechanism that can be described as Mechanism B followed by Mechanism A with an aldehyde formed inbetween. Click here for an animated illustration of the mechanism on a mechanism sheet. Note how this is the same mechanism as the reactions of esters with Grignard reagents, only with different nucleophiles (alkyl group vs. hydride).
3. Acid chlorides react with Gilman reagents to create ketones.
4. The Grignard/esters as well as acid chlorides/Gilmans are very specific with regard to the carboxylic acid derivative and reagents used. Do not "mix and match" reagents with different types of carboxylic acid derivatives.
5. A special reagent called DIBALH (diisobutyl aluminum hydride) can be used to reduce esters that stops at the aldehyde stage due to steric hindrance caused by the two isobutyl "antlers".
6. Amides react with LiAlH4 to give amines. The mechanism is Mechanism B in which the -OAlH3 leaves!!! followed by H- attack of a C=N bond. Remember to think of LiAlH4 as a nucleophilic H- attached to the Lewis acid AlH3.action mechanism describes the sequence of steps occurring during a reaction
7. In summary, you can make any of the less reactive carboxylic acid derivatives directly from any of the more reactive carboxylic acid derivatives by using the appropriate nucleophiles and reaction conditions.
8. However, you can make a more reactive carboxylic acid derivative from a less reactive carboxylic acid derivative if you first hydrolyze the less reactive carboxylic acid derivative to the carboxylic acid, then use SOCl2 to make the acid chloride, that, in turn, can make any of the other carboxylic acid derivatives.
Homework:
Read: Sections 19.1-19.3 in the ebook textbook. This text is part of the Longhorn Textbook access program.
Take the Daily Quiz 11 before 10 PM tomorrow. Click here to access the quiz.
Continue working on the Homework Problem Set 6, due at 10 PM on Monday, March 4. Click here to access the Homework Problem Set 6. Remember to do both the Aktiv learning and Gradescope portions of the homework! We will grade one problem for accuracy, and the rest for completeness.
