Alternative Methods

One alternative method to transform aldehydes into terminal alkynes is through the Wittig-Reactions, which yields either 1-1-dibromoolefins or vinylhalides. This two-step procedure, unliked the Ohira-Bestmann procedure, requires the use of strong bases and an environment at low temperatures under an inert gas atmosphere.

Another common approach is called Horner-Wadsworth-Emmons reaction, which uses the anion of dimethyldiazomethylphosphonate as a reagent. In this particular reaction, an aldehyde furnishes a vinylidenecarbene that spontaneously rearranges to the desire alkyne. The reagent, dimethyldiazomethylphosphonate, should be prepared freshly and must be isolated prior to metalation with n-BuLi or KOBu at -78°C.

Muller, S.; Liepold, B.; Roth, G. J.; Bestmann, H. J. Synlett 1996, 6, 521-522.