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Boronic Acid Products From Alfa Aesar

Boronic acids are the boron-containing analogues of the carboxylic acids. They are trivalent, the boron atom possessing two hydroxyl groups, with a third C-B bond filling the final valency.

Despite not occurring naturally they have a number of properties that make them increasingly important in organic synthesis - not least because of their relatively low toxicity and ‘green credentials'; they degrade down to the environmentally friendly boric acid.

The last 25 years has seen something of a revolution in the use and applications of this class of compounds and their standing, with the development of boronic acid-containing drugs, has never been higher. It is therefore not surprising to see that Alfa Aesar, a leading supplier of chemicals for research, development and production has recognised, and helped contribute to, this expanding field.

As is the case with other comparable acids, it is possible to produce alkyl-, aryl-, alkynyl- and alkenyl- acids. Alfa Aesar offer a comprehensive range of all these boronic acids, their esters, and also an extensive selection of the reagents, ligands and catalysts involved in their chemistry and applications.

Although frequently referred to as stable, most boronic acids do in fact spontaneously undergo dehydration at room temperature to form boroxines (cyclic trimeric anhydrides). It is fortunate that both acid and anhydride subsequently react, for most purposes, in a similar manner. Said reactions vary in whether it is the acid carbon-boron bonds or boron-oxygen bonds that are involved.

Reactions involving the C-O bond include boronate (cyclic boronic esters) production by reaction with diols. This is reaction proceeds ‘easily' and has lead to the use of boronic acids as derivatizing and protecting agents, particularly in carbohydrate chemistry, where they have also found a role in the design of artificial receptors and in selective transportation of sugars. Further important reactions involving the boronic acid C-O bond include the production of oxazaborolidines after reaction with chiral amino alcohols, and the synthesis of chiral boronates.

Reactions that involve cleavage of the C-B bond, displacing the boron moiety by an electrophilic species, include the now widely employed ‘Suzuki reaction' and the oxidative cleavage of arylboronic acids to give phenols. It is apparent that boronic acids, within the ever-expanding field of modern organic chemistry, are only going to become more important, and it is also apparent, that as a leading supplier and manufacturer of boronic acids, Alfa Aesar will be there for every exciting step of the journey.

Date added: 2015-05-25 11:48:29