Grignard reagents react with boronic acid

Many methods have been developed for synthesizing alkenyl and aryl boronic acids. For example, an aryl Grignard reagent reacts with trimethoxyborane, B(OCH3)3, which is commercially available, to give a dimethoxyaryl borane, AtB(OCH3)2. Hydrolysis of the borane ves the aryl boronic acid, as shown below. 

Not only Grignard reagents but also boronates may be employed as nucleophiles in iron-catalyzed cross-coupling. Aryl iodides and bromides react in a Suzuki-Miyaura-type coupling with arylboronic acids in the presence of 10 mol% iron(lll) chloride and a stoichiometric amount of potassium fluoride in ethanol at 100 °C under air to give the corresponding biaryl compounds with good to excellent yields (Scheme 4-227). ... 

Boronic acid chemistry has its roots in the work of Frankland, who in 1860 documented the preparation of ethylboronic acid, with the first synthetic publication on organoboron chemistry (The structures of boric acid and phenyl boronic acid are shown in Figure 4). " In 1880 Michaelis and Becker reacted borontrichloride and diphenyl mercury to form dichlorophenylborane. This in turn was added to water and recrystallised as white needles in the first synthesis of phenylboronic acid. The route was refined in 1909 and the classical synthesis of boronic acids from Grignard reagents and trialkyl borates was established. ... 

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