A Hydroxy‐Substituted Trialkyloxonium Ion and Its Oxonium Alkoxide Zwitterion

symmetric oxatriquinanetriol can be simply accessed by reaction of the tris-epoxide of 1,4,7-cyclononatriene with aqueous acid. The three OH groups of this hemispherical cation point into the endo space of the bowl and participate in strong intramolecular hydrogen bonding. A close balance in the dynamics of proton exchange between these hydroxy functions and amine bases is predicted by modeling. In practice, treatment of oxatriquinanetriol with the non-nucleophilic base 2-tert-butyl-1,1,3,3-tetramethylguanidine (Barton's base) leads to a zwitterionic oxonium alkoxide.