Rules of the Day 3-17-08

Click here for a copy of the mechanism sheet used in lecture today.

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. Acid chlorides react with Gilman reagents to create ketones via Mechanism B.

3. 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. A special reagent called DIBALH can be used which stops at the aldehyde stage.

4. 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.

5. The reactions described in 1-4. above 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 (an do not use NaBH4).

6. We have learned how chemists make amide bonds, namely with an acid chloride and an amine. Click on the following link then hit "Launch Video" so see how mother nature makes the amide bonds in proteins, namely with a ribosome. http://pubs.acs.org/cen/coverstory/85/8508cover.html

Homework:Continue Working on Homework Problem Set 7. It will be due before class on Wednesday, March 19. Reading: Sections 19.1-19.3Problems in Book: 19.1-19.6, 19.20, 19.21, 19.28, 19.29, 19.30 You will not turn these in but they are very helpful to PREPARE for the next lecture.