Previously, we were able to generate and spectroscopically characterize the (tertiary) oxocarbenium ions from various protected ketofuranoses and ketopyranoses, in superacidic solutions at low temperature. For such complex species, it was perhaps surprising that they were stable at all in superacidic media.

We have now extended this methodology to the even more reactive secondary oxocarbenium ions obtainable from various protected 2-deoxyaldoses. Through the measurement of J-couplings, this has allowed for the first determination of the conformation of these important intermediates in solution.