This Perspective describes general methods for the preparation of polyfunctional zinc organometallics and their use in Negishi cross-coupling reactions. Recent advances including new ligands and palladium catalysts are described. Related Negishi cross-coupling reactions involving Ni-, Cu-, Co-, and Fe-catalyzed cross-couplings are covered. The availability of a range of zinc organometallics combined with new efficient catalysts allows for efficient crosscoupling reactions with various organic electrophiles under usually mild conditions.

N-Acetylindoles can be oxidatively coupled with arenes such as benzene or pentafluorobenzene in dioxane. The use of Cu(OAc)(2) as the stoichiometric oxidant produces selective arylation at the 3-position of indole while AgOAc produces selective arylation at indole's 2-position.

We report a cobalt-catalyzed cross-coupling of di(hetero)arylzinc reagents with primary and secondary alkyl iodides or bromides using THF-soluble CoCl2 ⋅2 LiCl and TMEDA as a ligand, which leads to the corresponding alkylated products in up to 88 % yield. A range of functional groups (e.g. COOR, CN, CF3 , F) are tolerated in these substitution reactions. Remarkably, we do not observe rearrangement of secondary alkyl iodides to unbranched products. Additionally, the use of cyclic TBS-protected iodohydrins leads to trans-2-arylcyclohexanol derivatives in excellent diastereoselectivities (up to d.r.=99:1).

We report a robust and broadly applicable CoCl -catalyzed cross-coupling between functionalized aryl and heteroaryl zinc pivalates and various electron-poor aryl and heteroaryl halides (X=Cl, Br, I). Couplings with (E)- or (Z)-bromo- or iodo-alkenes proceed with retention of configuration. Also, alkynyl bromides react with arylzinc pivalates providing arylated alkynes.

A catalytic system consisting of CoCl2 ⋅2 LiCl (5 mol %) and HCO2 Na (50 mol %) enables the cross-coupling of various N-heterocyclic chlorides and bromides as well as aromatic halogenated ketones with various electron-rich and -poor arylzinc reagents. The reactions reached full conversion within a few hours at 25 °C.