Catalytic Degradation of Aliphatic Ethers using the Lewis Superacidic Bis(perfluoropinacolato)silane

The exceptional catalytic activity of a neutral Si(IV) Lewis superacid was highlighted on the degradation of oligo- and polyethers via ring closing metathesis. Model reaction experiments with diglyme and 1,5-dimethoxypentane outlined a significantly increased reactivity surpassing comparable Lewis acid catalyst presented in the literature. The high observed activity was explained by the kinetic effect of the bulky perfluorinated substituents, blocking a second coordination site that is responsible for catalyst deactivation by substrate chelation. Further experiments with aliphatic oligoethers outlined a gradual activity loss of the catalyst due to mechanistic disparities favoring side-reactions when more than one internal product unit is present. The extraordinary affinity for the cleavage of etheric C−O bonds was ultimately demonstrated by the reaction with diethylether, producing a pentavalent silicate species that was fully characterized including SC-XRD analysis.