An immobilized organocatalyst for cyanosilylation and epoxidation

An immobilized organocatalyst has been synthesized by covalently anchoring an N-octyldihydroimidazolium hydroxide fragment onto SiO2 (denoted as 1-OH/SiO2). This catalyst exhibits high catalytic performance for the cyanosilylation of various carbonyl compounds with trimethylsilyl cyanide (Me3SiCN). The effectiveness of the system is evidenced by the high to excellent yields of the corresponding trimethylsilyl ethers under mild reaction conditions, which are superior to those obtained with commercially available MgO and anion exchange resins. This catalyst also acts as a heterogeneous catalyst for the epoxidation of electron-deficient olefins with hydrogen peroxide. Further, the catalyst/product(s) separation can be easily carried out by the simple filtration (or centrifugation) and the reaction is immediately stopped by the removal of the solid catalyst, suggesting that the nature of the observed catalysis is truly heterogeneous.