Unit 6: Reaction Fundamentals

Organic chemistry becomes much easier when students see mechanisms as recurring patterns of electron flow rather than as disconnected reaction lists.

• Identify nucleophiles, electrophiles, leaving groups, and likely acid-base steps in a proposed mechanism.
• Use curved-arrow notation correctly to show electron-pair movement and bond-making/bond-breaking events.
• Interpret reaction-coordinate diagrams and distinguish activation energy from overall free-energy change.
• Relate structure, solvent, and conditions to rate, selectivity, and likely mechanistic pathway.

Checkpoint Questions

Q: What does the highest point on a reaction-coordinate diagram represent?

A: The transition state for that step; its energy relative to the reactants controls the rate of the step.

Q: Why do tertiary carbocations rearrange less often than primary carbocations?

A: They are already relatively stable, so there is less driving force for a shift to a lower-energy cation.