[gavinray]

Oh wow, now this is interesting.

To ELI5 this, what the commenter is saying is that you can take the "useless" L-Meth, and convert it to racemic, mixed D/L Meth.

Which you can then perform a second resolution step on, to convert/purify further, to the opposite chirality and get D-Meth.

The very interesting thing about this (if I were a clandestine chemist, or someone who wanted to get high at home), is that:

- AIBN is a readily available reagent, it's not difficult to acquire or would put you on any lists. This is in comparison to much of what you need for other synthesis techniques

- You can buy L-Meth legally over the counter. The extraction process would be a bit of a mess (quite literally) but should be doable, some basic recrystallization and/or conversion to freebase.

[hinoki]

To further ELI5, racemic means a mixture of left handed (Dextrorotatory) and right handed (Laevorotatory) versions of the same compound. Some molecules can have two different shapes that are mirror images of each other, and these different shapes can interact differently with our biology.

In this case, the right handed version is available in stores with no prescription, while the left handed version is a very controlled substance.