α-H-Übertragungsreaktionen an Vinylmetallverbindungen — Darstellung von (η5-Cyclopentadienyl) (η5-pentamethylcyclopentadienyl) — (2-methyliden)titanacyclobutan
摘要:
The reaction of Cp*CpTiCl*(2) (Cp*: C-5(CH3)(5); Cp: C5H5) with two equivalents of vinyllithium enables the first isolation of a titanium(IV)-divinyl complex Cp*CpTi(CH=CH2)(2) (11). In a molar ratio of 1:1 Cp*CpTi(CH=CH2)Cl (15) can be obtained and converted into Cp*CpTi(CH=CH2)CH3 (16) through further alkylation at a temperature above 0 degrees C a quantitative isomerisation of 11 to the methylidenemetallacyclobutane Cp*CpTiC(=CH2)CH2CH2 (12) occurs as a consequence of characteristic alpha-H-transfer. The influence on the stability of 11 and 16 through Cp*/Cp exchance will be discussed in comparison to Cp*Ti-2 derivatives on the basis of NMR data.