[organosurf]

Does anyone know if it is possible for a molecule of a secondary dibromo alkyl, Br-R1-Br ( eg R1 = 1,4-dibromo cyclohexane ) to undergo conventional Negishi coupling with two molecules ( or slight excess ) of a bromozinc alkylester, BrZn-R2 ( eg R2 = BrZnCH2COO.C2H5 ) to give R2- R1 – R2 ?
Will BOTH the Br in Br-R1-Br react together equally at the same rate ? If yes, and if there is a Journal reference mentioning dibromo couplings,similar to above, then kindly quote this.
All the Journal literatures and study is only about monobromo compounds ( Br – R ). No one has researched or mentioned about dibromo compound couplings. Your input will be appreciated,thanks.

[hailhail]

Alkyls generally don't couple well in palladium coupling, so you might need to play about with different catalysts (tri-tert-butylphosphine palladium is expensive but probably a good start if your standard tetrakis or bistriphenylphosphine dichloride palladium catalysts don't work). If you manage to find a catalyst it should be doable, assuming you can couple the zinc bromoester. As for the reaction rates I'm not sure, it depends on numerous factors including steric hindrance in the resulting product.

Try it and see is my only advice. If you're unsure if the zinc species will couple, try coupling with bromobenzene or something. If you find out it works and don't want to waste your zinc species, try coupling your alkyl bromide to a zinc species derived from a cheap Grignard.

[organosurf]

Will give your suggestion a go, thanks !