CH2CHZnBr

CH2CHZnBr, also known as vinylzinc bromide, is an organozinc compound with the chemical formula CH2CHZnBr. It is a reactive species used in organic synthesis as a source of the vinyl nucleophile. This compound is typically prepared by the reaction of a vinyl halide, such as vinyl bromide, with activated zinc metal. Alternatively, it can be generated in situ from vinyl Grignard reagents by transmetallation with zinc halides.

Vinylzinc bromide is a valuable reagent for forming carbon-carbon bonds through various cross-coupling reactions. It readily participates in Negishi coupling, a palladium-catalyzed reaction that couples organozinc reagents with organohalides or pseudohalides. This allows for the efficient synthesis of substituted alkenes and other unsaturated organic molecules. The vinyl group can also be transferred to aldehydes and ketones via addition reactions.

Compared to other vinyl organometallic reagents like vinyl Grignard or vinyl lithium compounds, vinylzinc bromide generally exhibits higher functional group tolerance and regioselectivity in coupling reactions. This makes it a preferred reagent in the synthesis of complex molecules where sensitive functional groups may be present. The compound is usually handled under inert atmosphere conditions due to its sensitivity to air and moisture.