W?oxo Adamantylidenes: Stable Molecular Precursors for Efficient Silica?Supported Metathesis Catalysts

Tungsten oxo adamantylidenes (=Ad) are a new class of readily accessible alkylidenes, that opens the possibility to evaluate broader molecular and supported olefin metathesis catalysts. In this context, W(O)(=Ad)X2, with X=pyrrolide perfluoro-tert-butoxide, were grafted on partially dehydroxylated silica, generate corresponding silica-supported tungsten adamantylidenes. The high thermal stability perfluoro-tert-butoxide complex, exists as dimer in solid state, even enables its grafting through sublimation. Evaluation their catalytic activities toward using standardized protocols show these species display activity internal terminal olefins. particular, avoiding use solvent during highly electrophilic compounds, can bind W center, enable significantly more active