Polysubstituted olefins as attractive and useful compounds are generally acquired by traditional acid or metal catalyzed system. Herein, a convenient and environmentally friendly method using acidic ionic liquid as a metal-free catalyst and dimethyl carbonate (DMC) as a green solvent has been demonstrated to synthesize polysubstituted olefins through construction of new CÀ C bonds by activating of ethers and alkenes. In the system, the usage of metal, halogen, traditional toxic solvents, and a large number of additives was avoided, neutralization after the reaction was not required, and waste production was reduced. The system was suitable for benzyl ethers and styrene derivatives, and recyclable [MeBs(dio)TMP][OTf] exhibited best activity. Density functional theory (DFT) calculations suggest synergistic functions of the cation and anion of ILs and show hydrogen bonds and π-π stacking interactions between catalyst and substrates, which can lead to lower barriers.

We have established H3PW12O40·xH2O catalyzed O-alkylation of oximes with alcohols in DMC, and investigated the corresponding mechanism.