Grignard reagents Suzuki reaction

Completely aromatic, hyperbranched polyphenylenes were synthesized as monodendrons from AB2 type monomers by Kim and Webster [111, 112]. These dendrimers were prepared either by the homocoupling of 3,5-dibromophenyl boronic acid under modified Suzuki conditions, or by aryl-aryl coupling reactions involving 3,5-dihalo-phenyl Grignard reagents in the presence of Ni(II) catalysts as shown in Scheme 7. 

Suzuki [59] also shows the high Sn2 selectivity of the reaction between allyl acetates and Grignard reagents by Li2CuCl4 catalysis in THF but modification of the nature of the solvent, temperature, quantity of catalyst, and the Grignard reagent used, had a moderate elTect on the regioselectivity [Eq. (46) and Table 9]. 

The Kumada reaction offers a more direct approach to the desired products compared with Suzuki and Negishi reactions. However, the Kumada reaction shows poorer functional group compatibility. When the substrates tolerate the background reactivity of a Grignard reagent, the Kumada reaction is a powerful tool to construct new carbon-carbon bonds. 

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