[Reelin]

> but how do researchers even figure out how to make these reactions happen?

Disclaimer: I'm terrible at organic chemistry.

As with software engineering, you develop a general sense (I didn't) of what might work and what probably won't. You aren't coming at it blind and reinventing the wheel every time. You learn to recognize patterns in chemical structures and reason about how they will interact under various conditions based on that. You do electron pushing in your head without giving it much thought, similar to a programmer reasoning about object lifetimes or dataflow in an application.

As to -100 C or +5 atm, that's the easy part. You alter environmental conditions when what you're working with is too reactive, or not reactive enough, or you have some other general problem. It's roughly analogous to determining the minimum amount of RAM the machine hosting your production database requires.