As mentioned in my new video, Elemental Extractions 5: Boron, I've been doing a lot of research on the element and how to isolate it. My chosen reaction for that video (and my old one on boron) was the magnesiothermic reduction of boric oxide:
B2O3 + 3Mg == 2B + 3MgO
But it turns out that this pathway only produces very impure boron, for several reasons. Read on for some of the results of my research, with links to the papers I mention. You can also see my thread on ScienceMadness for some extra discussion.