ω-Phenylalkyl-substituted zirconocene dichloride complexes as catalyst precursors for homogeneous ethylene polymerization
作者:Erik H Licht、Helmut G Alt、M.Manzurul Karim
DOI:10.1016/s0022-328x(00)00009-7
日期:2000.4
The reaction of ω-phenyl-1-bromoalkanes with cyclopentadienyl sodium, indenyl lithium or fluorenyl lithium forms ω-phenylalkyl-substituted ligand precursors in high yields. The corresponding anions react with zirconium tetrachloride to give ω-phenylalkyl-substituted zirconocene dichloride complexes. After activation with methylaluminoxane, these complexes are highly active catalysts for homogeneous
Asymmetric Electrophilic Fluorocyclization with Carbon Nucleophiles
作者:Jamie R. Wolstenhulme、Jessica Rosenqvist、Oscar Lozano、John Ilupeju、Nathalie Wurz、Keary M. Engle、George W. Pidgeon、Peter R. Moore、Graham Sandford、Véronique Gouverneur
DOI:10.1002/anie.201304845
日期:2013.9.9
helical‐shaped fluorinated tetracyclic molecules were prepared by fluorocarbocyclization of prochiral alkenes. The development of a new class of chiral Selectfluor (1) proved instrumental in developing an asymmetric variant of this transformation. These novel chiral N‐F reagents are readily accessible by fluorine transfer from shelf‐stable N‐fluoropyridinium salts.
An efficient intermolecular carbon-carbon bond formation via SmI2-promoted anion radical alkylation
作者:Osamu Ujikawa、Junji Inanaga、Masaru Yamaguchi
DOI:10.1016/s0040-4039(00)99138-x
日期:1989.1
Anion radicals generated from the corresponding ketones with the efficient one electron transfer system, SmI2-THF-HMPA, attacked a variety of activated olefins at room temperature affording the corresponding addition products in good to excellent yields, some of which are hardly accessible by the conventional nucleophilic alkylation of ketones.
Unbridged metallocene dichloride complexes with mono-substituted indenyl ligands and their application for the polymerization of propene
作者:Roland Schmidt、Helmut G Alt
DOI:10.1016/s0022-328x(00)00776-2
日期:2001.3
synthesis of unbridged metallocene dichloride complexes of the type Ind′2ZrCl2 (Ind′=2-alkyl- or arylalkyl-substituted indenyl) is described. The complexes are characterized by 1H- and 13C-NMR spectroscopy and mass spectrometry. After activation with methylalumoxane these complexes can be used for propenepolymerization; they produce block copolymers consisting of alternating isotactic and atactic blocks