I recently was doing up a nice old jazz standard, “All The Things You Are”. It has a very pretty progression and takes very well to using a lot of 2-5-1 transitions between chords. There's a moment in the first verse where there is the perfect opportunity to play a minor 2-5-1 going into a cmin7 chord. SO of course your progression, as everyone typically accepts the minor 2-5-1, should be a d half diminished, G dominant, into the c minor 7. Now, this had never struck me before because I had just generally accepted that that's how everyone plays the 2-5-1, but now I realized that if I play a G dominant 7, it's third is B, a half step above the seventh of cmin7. This makes your progression harmonically incorrect. I was puzzling over this for a while, curious as to why the minor 2-5-1 is played this way, when I realized the answer: the common minor 2-5-1 is not derived from the natural minor scale, but rather the melodic minor scale. The melodic minor scale is an alteration of the natural minor in which one raises the sixth and seventh step of the scale when ascending, and then makes them natural again descending. SO in the minor 2-5-1, one ascends from the 2 to the five, meaning that you need to raise the seventh step of the scale up, which is actually the third of the 5 chord. Then you natural that to make it into the regular minor seventh of the root chord because you have descended from the fifth to the root. Not only was this a really cool thing to think about and figure out, it also provides you with another way of soloing over minor 2-5-1, something that is one of the most important skills for playing jazz. You can play over the minor 2-5-1 using the melodic minor scale, something which will sound interesting and unusual and will create an intriguing dissidence that you can resolve by descending on the natural minor once you hit the root chord. I thought this was an interesting thought to share that someone might be interested in.

Edstar221
I thought this was an interesting thought to share that someone might be interested in.

Thanks for sharing! It's great making these breakthroughs yourself.

For anyone who wants to review the melodic vs natural minor scale, check out this video:
https://www.youtube.com/watch?v=Q7WqKpD7w4Q