17. Reaction Analogies and Carbonyl Reactivity

Freshman Organic Chemistry (CHEM 125)

Continuing the examination of molecular orbital theory as a predictor of chemical reactivity, this lecture focuses on the close analogy among seemingly disparate organic chemistry reactions: acid-base, SN2 substitution, and E2 elimination. All these reactions involve breaking existing bonds where LUMOs have antibonding nodes while new bonds are being formed. The three-stage oxidation of ammonia by elemental chlorine is analyzed in the same terms. The analysis is extended to the reactivity of the carbonyl group and predicts the trajectory for attack by a high HOMO. This predicted trajectory was validated experimentally by Bürgi and Dunitz, who compared numerous crystal structures determined by X-ray diffraction.

00:00 - Chapter 1. Similarities Among Acid-Base, SN2 Substitution, and E2 Elimination Reactions
15:23 - Chapter 2. The Oxidation of Ammonia by Chlorine in Molecular Orbital Terms
26:05 - Chapter 3. Reactivity of the Carbonyl Group
36:11 - Chapter 4. Dunitz and Burgi's Experimental Results on Carbonyl Attack Trajectory

Complete course materials are available at the Open Yale Courses website: http://open.yale.edu/courses

This course was recorded in Fall 2008.