α-Hydroxy-Tetrazoles as Latent Ethynyl Moieties: A Mechanistic Investigation

This article focuses on the dehydration of -hydroxy-tetrazoles, leading to tetraazafulvenes and then to vinylic carbenes that rearrange into ethynyl moieties through the Fritsch-Buttenberg-Wiechell rearrangement. Each step of this sequence was scrutinized, either by examination of the substrate and/or dehydrating agent scope, or through AM1 calculations, in order to understand the limiting step of this process. This underrated transformation appears to be a viable alternative to existing methods used for transforming aldehydes into alkynes.