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The general structure of a phosphite ester showing the lone pairs on the P. In organic chemistry, a phosphite ester or organophosphite usually refers to an organophosphorous compound with the formula P(OR) 3. They can be considered as esters of an unobserved tautomer phosphorous acid, H 3 PO 3, with the simplest example being trimethylphosphite ...
Phosphonites are generally more reactive than phosphite esters. They react to produce phosphinates. Heating is also required for the reaction, but pyrolysis of the ester to an acid is a common side reaction. The poor availability of substituted phosphonites limits the usage of this class of reagent in the Arbuzov reaction.
The mechanism starts with an allylic sulfoxide 1 which undergoes a thermal 2,3-sigmatropic rearrangement to give a sulfenate ester 2. This can be cleaved using a thiophile, such as phosphite ester , which leaves the allylic alcohol 3 as the product.
Various specialised methods have been developed on the laboratory-scale for scientific investigations. These are rarely employed in bulk manufacturing. Examples include the Atherton-Todd reaction, which converts a dialkyl phosphite to a phosphoryl chloride. This can then react with an alcohol to give an organophosphate and HCl.
When the substituent on the other hand is phenyl (not shown) the phosphite has a preference for reaction with the acyl group leading to an ethyl enol ether. Key in explaining the difference in reactivity is the electron density on the α-keto carbon atom. Perkow quinoline application
Since orthophosphoric acid has three −OH groups, it can esterify with one, two, or three alcohol molecules to form a mono-, di-, or triester. See the general structure image of an ortho- (or mono-) phosphate ester below on the left, where any of the R groups can be a hydrogen or an organic radical. Di- and tripoly- (or tri-) phosphate esters ...
Phosphites, sometimes called phosphite esters, have the general structure P(OR) 3 with oxidation state +3. Such species arise from the alcoholysis of phosphorus trichloride: PCl 3 + 3 ROH → P(OR) 3 + 3 HCl. The reaction is general, thus a vast number of such species are known.
The phosphite esters and tertiary phosphines also effect reduction: ROOH + PR 3 → P(OR) 3 + ROH. Cleavage to ketones and alcohols occurs in the base-catalyzed Kornblum–DeLaMare rearrangement, which involves the breaking of bonds within peroxides to form these products.