There is no direct relation between focal length and minimum focal distance.
Usually a long focal length means a long minimum focal distance, but that is just because a lens built that way also has other characteristics that are preferable, like having a reasonable focus range.
If you add extension tubes between the lens and the camera, the minimum focal distance will be shorter. That's because you change the characteristics of the lens. With enough extension tubes you can even get a negative minimum working distance (the distance between the front of the lens and the subject), i.e. it can focus behind the front lens element. That shows that you could easily build a lens with any focal length and a very short minimum focal distance, but it would also have a very short focus range.