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.

Automated summary

The exceptional catalytic activity of a neutral Si(IV) Lewis superacid was demonstrated in the degradation of oligo- and polyethers via ring closing metathesis. The catalyst showed significantly higher reactivity than comparable Lewis acid catalysts reported in the literature. The high activity was attributed to the bulky perfluorinated substituents blocking a coordination site responsible for catalyst deactivation. However, the catalyst exhibited gradual activity loss when multiple internal product units were present due to mechanistic disparities favoring side-reactions. The cleavage of etheric C-O bonds was ultimately demonstrated by the reaction with diethylether, forming a fully characterized pentavalent silicate species.