2-Formylphenylboronic Acid

Abstract

[40138-16-7] C7H7BO3 (MW 149.94) InChI = 1S/C7H7BO3/c9-5-6-3-1-2-4-7(6)8(10)11/h1-5,10-11H InChIKey = DGUWACLYDSWXRZ-UHFFFAOYSA-N (a reagent and substrate that participates in palladium-catalyzed coupling reactions2-9 as well as other metal-catalyzed reactions,10-14 is commonly employed in reductive amination reactions15-18 and certain three-component reactions,19, 20 and as a precursor for other boron derivatives21-24) Physical Data: mp 115–120 °C (contains varying amounts of the anhydride). Solubility: soluble in water (sparingly) and in most of the organic solvents. Form Supplied in: white crystalline solid. Analysis of Reagent Purity: HPLC, IR, NMR. Preparative Methods: refluxing 2-bromobenzaldehyde, ethylene glycol and p-toluenesulfonic acid in toluene for 6 h provides the protected aldehyde. Addition of the aryl bromide to Mg in THF, followed by transfer of the resulting Grignard reagent to a solution of trimethyl borate in THF (−78 °C to room temperature), and subsequent hydrolysis provides the product.25 2-Formylphenylboronic acid can also be prepared by reaction of o-tolylboronic acid with N-bromosuccinimide followed by reaction at reflux with benzoyl peroxide for 6 h.26 Purification: recrystallization from water26 or CH2Cl2/hexane.27 Handling, Storage, and Precautions: the compound should be handled with protective gloves and eyewear in a ventilated area. The compound is stable, but care should be taken to avoid contact with strong oxidizing agents. Hazardous decomposition products include carbon monoxide, carbon dioxide, and boron oxides.