How to pronounce“cycloaddition”in English

Let’s try lining up our orbitals for the cycloaddition again.

So with UV light, cycloaddition can occur – so we say that the photochemical reaction is allowed.

So we say the thermal reaction is forbidden in the cycloaddition world.

And, besides the cycloaddition we just learned, two more happen thanks to the Sun interacting with our bodies.

The pyrimidine dimers we saw at the beginning of the episode are a cycloaddition, and we can draw arrows for the mechanism like this.

In this episode, we saw: The Diels-Alder reaction is a cycloaddition that gives very specific stereochemistry and regiochemistry because of molecular orbital interactions,

We've been talking about the Diels-Alder reaction this whole time, but it's just one example of a cycloaddition, a type of ring-forming reaction where two new bonds form simultaneously.