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Tetrahydropyran (THP) is the organic compound consisting of a saturated six-membered ring containing five carbon atoms and one oxygen atom. It is named by reference to pyran, which contains two double bonds, and may be produced from it by adding four hydrogens.
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]
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.
[2] [3] Boronic acids, and boronic esters are common boryl groups incorporated into organic molecules through borylation reactions. [4] Boronic acids are trivalent boron-containing organic compounds that possess one alkyl substituent and two hydroxyl groups. Similarly, boronic esters possess one alkyl substituent and two ester groups.
The reaction is much slower with ketones than aldehydes. [41] 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: [42] Trifluoroborate salts are stabler than boronic acids and selectively alkylate aldehydes ...
Protodeboronation is a well-known undesired side reaction, and frequently associated with metal-catalysed coupling reactions that utilise boronic acids (see Suzuki reaction). [1] For a given boronic acid, the propensity to undergo protodeboronation is highly variable and dependent on various factors, such as the reaction conditions employed and ...
In aqueous solution, boric acid B(OH) 3 can act as a weak Brønsted acid, that is, a proton donor, with pK a ~ 9. However, it more often acts as a Lewis acid, accepting an electron pair from a hydroxide ion produced by the water autoprotolysis: [11] B(OH) 3 + 2 H 2 O ⇌ [B(OH) 4] − + H 3 O + (pK = 8.98) [12]
The reaction of boron trichloride with alcohols was reported in 1931, and was used to prepare dimethoxyboron chloride, B(OCH 3) 2 Cl. [3] Egon Wiberg and Wilhelm Ruschmann used it to prepare tetrahydroxydiboron by first introducing the boron–boron bond by reduction with sodium and then hydrolysing the resulting tetramethoxydiboron, B 2 (OCH 3) 4, to produce what they termed sub-boric acid. [4]