Rules of the Day 3-30-07

Click here for today's lecture mechanism sheet

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. An enamine ("aka mini me") is formed when a secondary amine reacts with a ketone or aldehyde. The enamine can be thought of as the resonance hybrid of two contributing structures. The b-carbon atom is nucleophilic entirely analogous to an enolate. (Yes, you guessed it, "mini me" reacts as a nucleophile like Dr. Evil! Seriously folks, I don't make this stuff up).

3. Enamines can be alkylated by reaction with alkyl halides, or acylated by reaction with acid chlorides.

4. alpha,beta-unsaturated carbonyl species are electrophilic functional groups in which the enolate (or aenamine) nucleophile attacks the b carbon atom, not the carbonyl carbon (also known as "1,4 conjugate addition"). This process, referred to as a Michael reaction, creates a new carbon-carbon bond and retains the carbonyl in the product.

Homework: There is no homework to turn in next week because I want you to concentrate on doing the following homework over this weekend. These are great problems, on the challenging side, and there is no need to make more for you to do. PLEASE DO THE READING AND THESE PROBLEMS EVEN THOUGH YOU DO NOT NEED TO TURN THEM IN!!! Read: 19.6-19.8A, all of Chapter 20 Problems 19.7-19.15, 19.41, 19.45, 19.48, 19.52, 19.53, 19.55, 19.57 (Great one!)