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Please login to access the full content or check if you have access via Variation 3: Reactions with Organometals Containing Electropositive Metals

DOI: 10.1055/sos-SD-002-00797

Negishi, E.-i.; Takahashi, T.Science of Synthesis, (20032759.

In addition to relatively electronegative metals discussed in Section, relatively electropositive metals, such as lithium, magnesium, zinc, and aluminum, have also been shown to participate in transmetalation or σ-bond metathesis with zirconacycles. For example, the reaction of a zirconacyclopentane derivative, such as 181, with 2 equivalents of an alkyllithium gives a most intriguing bimetallic complex containing only one cyclopentadienyl group, e.g. 236, in which the 2,3-dialkyl-1,4-tetramethylene moiety is flux­ional, thereby rendering its two halves magnetically equivalent; however, the two hexyl moieties are magnetically nonequivalent (Scheme 98).[‌261‌] Facile displacement of the cyclopentadienyl group appears to occur predominantly with organolithiums, but may also be possible with other organoalkali metals.

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