REACTION OF ETHER AND THIOETHER FUNCTIONALIZED 1-ALKENES WITH THE CATIONIC PERMETHYLZIRCONOCENE OLEFIN POLYMERIZATION CATALYST [(ETA(5)-C5ME5)(2)ZRME](- MOLECULAR-STRUCTURE OF THE INSERTION PRODUCT [(ETA(5)-C5ME5)(2)ZRCH2CH(ME)CH2OET](+)() )

Reaction of [(eta(5)-C5Me5)(2)ZrMe][MeB(C6F5)(3)] (1) with (thio)ether functionalised alkenes: 3-ethoxy-1-propene and 3-(methylthio)-1 prope ne gives stable insertion products [(eta(5)-C5Me5)(2)ZrCH2CH(Me)CH2XR] [MeB(C6F5)(3)] (2: X = 0, R = Et 3. X = S, R = Me) in which the (thio) ether function is intramolecularly coordinated to zirconium. The molec ular structure of 2 shows a regular 1-oxa-2-zirconacyclopentane in an envelope conformation. The metallacycles in 2 and 3 are stable toward further insertion of (functionalised) alkenes and cannot be activated for ethene polymerisation by pre-complexation of the (thio)ether funct ion with strong Lewis acids (AlCl3, MgCl2, B(C6F5)(3) or [Ph3C](+)). T he strong alkylating co-catalyst Me3Al regenerates complex 1 by exchan ge of the (thio)ether function for methyl and thus initiates polymeris ation of ethene. (C) 1998 Elsevier Science S.A.