Die Bildung eines Zirconium-substituierten Phosphor-Ylids durch sigmatrope Wasserstoffverschiebung / Formation o f a Zirconium Substituted Phosphorus Ylide by Sigmatropic Hydrogen Migration
Open Access
- 1 September 1985
- journal article
- Published by Walter de Gruyter GmbH in Zeitschrift für Naturforschung B
- Vol. 40 (9) , 1177-1180
- https://doi.org/10.1515/znb-1985-0914
Abstract
σ-Crotylmetallocenyl substituted ylides (1) Cp2M(-CH2CH=CHCH3)(CHPPh3), M=Zr,Hf, are formed upon treatment of a mixture of (s-cis-) and (s-trans-η4-butadiene)metallocene complexes with the phosphorus ylide methylenetriphenylphosphorane (4). From the ( s-cis-/s-trans-butadiene) zirconocene equilibrium mixture (7/5) only the (s-cis-conjugated diene)metallocene isomer reacts with the ylide at -50 °C. Under kinetic control the fram-σ-crotylzirconocenyl-ylide (lb) is formed selectively; subsequent crotyl cis-trans-isomerization (1b⇆1b′) takes place at higher temperature (> -20 °C ). A mechanism including a concerted intramolecular homo-1,5- hydrogen migration step is proposed.Keywords
This publication has 0 references indexed in Scilit: