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DOI: 10.1055/sos-SD-007-00562

Takahashi, T.; Liu, Y.Science of Synthesis, (20047618.

Ethylmagnesiation of alkynes is rather difficult. One reason is that alkynes readily dimerize on zirconium(II) species to give zirconacyclopentadienes, which do not react with ­ethylmagnesium bromide. This reaction can be circumvented by the use of diynes, which do not dimerize. Octa-3,5-diyne (59) reacts with ethylmagnesium bromide in the presence of 30mol% of dichlorobis(η5-cyclopentadienyl)zirconium(IV) in tetrahydrofuran at 50°C. The ethylmagnesiation product 60 is obtained in 70% yield (Scheme 43).[‌169‌]

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