Die Reaktivitaetsabstufung von Trimethylsiloxygruppen gegenueber dem Hydrozirconierungsreagenz Cp2Zr(H)Cl

Article abstract of DOI:10.1016/0022-328X(90)85217-M

The trimethylsilylethers of unsaturated alcohols yield different compounds on reaction with Cp2Zr(H)Cl (1) depending on the length and branching of the alkenyl chain.With the hex-1-en-6-ol derivative the usual product of hydrozirconation is obtained in high yield.The reaction of the silylated 3-methyl-but-1-en-3-ol (11) is however, accompanied by hydrogenation of the Si-O bond.The main products are trimethylsilane and the yellow complex Cp2Zr(Cl)CH2CH2C(CH3)2OZr(Cl)Cp2 (12).The molar ratio of the reactants determines the final products of the reaction of allyl trimethylsilyl ethers 3 and 1.An equimolar preparation yields mainly the usual product of hydrozirconation, whereas an excess of 1 favours the formation of a binuclear five-membered chelate (5) and trimethylsilane.CO inserts readily into the Zr-C bond of 12, but 5 does not react with CO.The binuclear structure of 12 was established by an X-ray diffraction study.The character of the Zr-O and Zr-C bonds is discussed in terms of these results.