Rules of the Day 3-21-08

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

1. There are four new concepts associated with chapter 19. Click on these one at a time to get more information.

A) Reactions favor the formation of weaker bases at equilibrium (provides a motive), so you need to have a Table of pKa values

B) Enolates as nucleophiles

C) Beta-Dicarbonyl species are especially acidic

D) Conjugate addition to alpha,beta unsaturated carbonyl species.

2. The classic aldol reaction combines two molecules of the same aldehyde. A complex mixture results (four different consititutional isomers plus stereoisomers) when two different aldehydes are used and both of them can make enolates. You can see a movie of the aldol reaction by clicking here.

3. Aldol products can dehydrate to give a mixture of E and Z alpha,beta unsaturated aldehydes when heated in dilute acid. The more stable alkene (usually E) generally predominates.

Homework: Begin studying for next week's midterm! Read: No new reading Problems: 19.22, 19.23, 19.24, 19.25, 19.31, 19.33. You will not turn these in but they are very helpful to PREPARE for the next lecture.