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Phenylboronic acid or benzeneboronic acid, abbreviated as PhB(OH) 2 where Ph is the phenyl group C 6 H 5 - and B(OH) 2 is a boronic acid containing a phenyl substituent and two hydroxyl groups attached to boron. Phenylboronic acid is a white powder and is commonly used in organic synthesis.
[18] [19] The acid-catalysed process is dependent on a reaction between boronic acid and an acid, such as sulfuric acid. On the other hand, the base-catalysed process arises from a pre-equilibrium between boronic acid and hydroxide to form the corresponding boronate, this is usually followed by a rate-limiting reaction between boronate and ...
The general structure of a boronic acid, where R is a substituent.. A boronic acid is an organic compound related to boric acid (B(OH) 3) in which one of the three hydroxyl groups (−OH) is replaced by an alkyl or aryl group (represented by R in the general formula R−B(OH) 2). [1]
The boron atom of a boronic ester or acid is sp 2 hybridized possessing a vacant p orbital, enabling these groups to act as Lewis acids. The C–B bond of boronic acids and esters are slightly longer than typical C–C single bonds with a range of 1.55-1.59 Å. The lengthened C–B bond relative to the C–C bond results in a bond energy that ...
The reaction is much slower with ketones than aldehydes. [40] For example, in Nicolaou's epothilones synthesis, asymmetric allylboration (with an allylborane derived from chiral alpha-pinene) is the first step in a two-carbon homologation to acetogenin: [41] Trifluoroborate salts are stabler than boronic acids and selectively alkylate aldehydes ...
Boranes are chemical compounds of boron and hydrogen, with the generic formula of B x H y. These compounds do not occur in nature. Many of the boranes readily oxidise on contact with air, some violently. The parent member BH 3 is called borane, but it is known only in the gaseous state, and dimerises to form diborane, B 2 H 6. The larger ...
The hydrogen ion, or hydronium ion, is a Brønsted–Lowry acid when dissolved in H 2 O and the hydroxide ion is a base because of the autoionization of water reaction H 2 O + H 2 O ↽ − − ⇀ H 3 O + + OH − {\displaystyle {\ce {H2O + H2O <=> H3O+ + OH-}}}
The reaction thus provides a more stereospecific and complementary regiochemical alternative to other hydration reactions such as acid-catalyzed addition and the oxymercuration–reduction process. The reaction was first reported by Herbert C. Brown in the late 1950s [2] and it was recognized in his receiving the Nobel Prize in Chemistry in 1979.