A CYCLOMETALATED ARYLOXY(CHLORO)NEOPENTYLIDENETUNGSTEN COMPLEX - A HIGHLY-ACTIVE AND STEREOSELECTIVE CATALYST FOR THE METATHESIS OF CIS-2-PENTENE, AND TRANS-2-PENTENE, NORBORNENE, 1-METHYL-NORBORNENE, AND ETHYL OLEATE

The intramolecular C-H activation of a diphenylphenoxy ligand by an electrophilic W(VI) center is the crucial step in the synthesis of the extremely active and stereoselective metathesis catalyst 1 formed from [WCl3(CCMe3)(dme)] or [WCl4(O-2,6-C6H3Ph2)2]. In the metathesis of ethyl oleate, replenishing of the catalyst is not required; 500 moles of substrate per mole of 1 are converted in one hour at 25-degrees-C.