Rules of the Day 4-13-09 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. Adjacent 2p orbitals overlap, allowing the pi electron density to delocalize into all the adjacent 2p orbtials , their wave functions adding constructively to provide for extra stability . ( See Golden Rule #7 ). 3. H-X and X 2 add to conjugated dienes to give both 1,2 and 1,4 addition products , via a resonance stabilized allylic cation intermediate. 4. The 1,2 addition is usually the kinetic product , that is, it forms faster (better opportunity since the reaction is occuring at a more stabilized secondary carbocation), but the 1,4 addition product is the thermodynamic product because it is more stable (greater motive since the double bond
This is the end of the preview. Sign up
access the rest of the document.