Synthesis of New Dialkylmagnesium Compounds by Living Transfer Ethylene Oligo- and Polymerization with Lanthanocene Catalysts

摘要

Considerable interest has been devoted to oligomerization and polymerization of ethylene on transition metal catalysts. The aim of these reactions is to produce higher olefms (Alfen. Aiphabutol. SHOP processes) or polymers of higher molecular weight(Ziegler--Natta catalysis). Such reactions and those with the relatively recently discovered metallocene-based catalysts produce linear, vinyl-terminated chains, which can be transformed by the use of stoichiometric amounts of zirconocene compounds intofunctionalized compounds. This kind of functionalized oligomers, however, can be obtained by anionic polymerization of ethylene with n-butyllithium followed by electrophihc substitution of the resulting living oligorner. In contrast, organomagnesium compounds have been synthesized from olefms by using zirconocene-based catalysts and dialkyl-magnesium compounds or Grignard reagents as coreactants. and zirconium tetrachloride has been used as catalyst for the synthesis of diaikylmagnesium compounds fromMgH, and α-olefins, a process, which could be followed by ethylene addition, but only under severe conditions.