Haloarene boronic acids

On the other hand, aromatic monomers containing a boronic acid function apart from a halide function, i.e. haloarene boronic acids, undergo coordination homopolycondensation in the presence of transition metal-based catalysts, which results in the formation of poly(arylene)s [2] ... 

The cross-coupling protocol provides a valuable method for homologation of arylboronic acids or direct borylation of haloarenes. The coupling takes place at the Sn-C bond in preference to the boronic ester because the B-C bond is inert to biaryl coupling in the absence of a base (Eq. 11). Bulky 1,3-diphenylpropandiol protects boronic acid during... 

The aryl (or alkyl) palladium species needed for a Heck reaction can be generated fi om boronic acids and their derivatives if the overall reaction is conducted under oxidative conditions. In contrast to haloarenes, transmetalation is leaving the metal oxidation state unchanged. Therefore, an additional oxidant is needed to gain back Pd(ll) after a completed catalytic circle. So-called oxidative Heck reactions have been reported for the first time by Cho and Uemura and Karami et al The group of Park has shown that enamides are suitable substrates for this carbopalladation mode (Scheme 5-40). ... 

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