The Ohira-Bestmann Reaction: Pro or Con?
Posted by Cat Herder on June 12, 2008
A major portion of my research on the way to getting a fancy hoodie and sweet-ass piece of paper deals with the reactions of alkynes. For those of you not in the know, an alkyne is what chemists call two carbons with three bonds between them. Think of it as a giant clusterfuck of electrons sandwiched between two carbon nuclei.
But I digress, making these things can be a bit trying and there really aren’t many ways to do it well. However, there is one method for making terminal alkynes that I have a particularly schizophrenic relationship with; the Ohira-Bestmann Homologation.
Sometimes it works, sometimes it doesn’t. You have to make the diazophosphonate from tosyl azide (think explody meets colorless maple syrup). The yields are never as high as you think they will be. If the other method to make alkynes from aldehydes wasn’t the dreaded Corey-Fuchs, I would never run this bitch again.