Grignard reagent zinc halide reaction with

Zinc forms numerous organometallic compounds, with the dialkyls being the most important. Although these compounds do not associate to give aggregates, they are spontaneously flammable. The reaction of a zinc halide with a Grignard reagent can be used to prepare the compounds. 

Thienylmagnesium or zinc derivatives can be coupled with vinyl halides, bromo- or iodobenzene, or ethynyl bromide under Ni or Pd catalysis (Scheme 148) a thien-2-yl Grignard reagent was coupled twice to 3,6-dibromocar-bazole using nickel catalysis <1997CM1578>. The reaction can be extended to the synthesis of -styrylthiophene in this case the double-bond configuration is retained in the product. 

---