Ethenylmagnesium bromide

Alkenyl, alkynyl, and aryl halides, like alkyl halides, can be converted to the corresponding magnesium and lithium compounds. However, the reaction conditions, such as choice of solvent, can be critical. Bromoethene, for instance, can be converted to ethenylmagnesium bromide in good yield if the solvent is oxacyclopentane [tetrahydrofuran, (CH2)40] ... 

Membered macrocycle 26 containing four phosphorus atoms was synthesized from tert-butylphosphinous dichloride and ethenylmagnesium bromide in 11% isolated yield (Scheme 12.10). The cis-trans isomer was the only one observed for 9-membered cyclic compound 27 and all-trans for 12-membered 26. The all-trans isomer was isolated in a pure state [46]. 

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