| abstract |
Method of making an immobilized tungsten catalyst comprising or consisting of (≡SiO)X W(═O)(═CR1R2)(R3 or R4)2-x(L)z, comprising at least the following step (i): (i) reacting silica (Si02) with a tungsten oxo alkylidene complex comprising or consisting of (R3)(R4)W(═O)(═CR1R2)(L)y, preferably wherein ═CR1R2 is selected from ═CHC(CH3)3 or ═CH(C(CH3)2)C6H5 and R3 and R4 are independently selected from pyrrol-1-yl, 2,5-dimethylpyrrol-1-yl, or 2,5-diphenylpyrrol-1-yl, or —OR, wherein R is a six membered or 10 membered aryl ring, optionally substituted. |