Mechanisms Like Chords

by Kiley Lynch

When I was learning how to play guitar (badly!) in high school, one of the cool things was learning that SO MANY songs – thousands!!!! – could be played with a handful of chords. It’s amazing what you can do with G, C, and D.

Here’s the most important piece of advice I can give you about carbonyl chemistry.

Just like songs, every mechanism you will learn is built up out of a SMALL number of steps (“chords”). And the steps repeat, again and again.

Here are the 5 most important mechanistic steps you learn in carbonyl chemistry.

  1. Addition (break C-O pi bond, form new bond to C)
  2. Elimination (form C-O pi bond, break new bond to C)
  3. Protonation (remember – speeds up addition reactions)
  4. Proton transfer (usually occurs before elimination, because we’re making a better leaving group)
  5. Deprotonation (usually the last step, to get a neutral product).

Every new reaction you learn, try to identify each individual mechanistic step.

Then, make a little abbreviation for each step (A, E, P, D, Pt)

Go through some of the mechanisms you’ve learned so far and try to identify the patterns according to this.

You will be amazed by how much the patterns repeat.

More tomorrow.

Here’s a sneak preview of how knowing a small number of mechanistic steps can help you see the patterns behind dozens of reactions.
Thanks for reading! James

P.S. Have you seen this video by Axis of Awesome? Same principle!