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The name acyloin is derived from the fact that they are formally derived from reductive coupling of carboxylic acyl groups (−C(=O)OH). [1] They are one of the two main classes of hydroxy ketones , distinguished by the position of the hydroxy group relative to the ketone; in this form, the hydroxy is on the alpha carbon , explaining the ...
Although examples of enantioselective α-ketol rearrangements starting from achiral α-hydroxy ketones are fairly limited, a number of examples of 1,2-asymmetric induction (due to stereoelectronic factors) have been observed. In one example of an enantioselective process, use of nickel(II) diacetoacetonate and pybox provided 4 in 34% ee. [11] (4)
Alpha-hydroxy ketones are also called acyloins. [1] They are commonly formed by condensation or reductive coupling of two carbonyl (C=O) compounds or oxidation of ketones. The simplest such compound is hydroxyacetone. If the alcohol is primary, alpha-hydroxy ketones give a positive Fehling's test. Beta-hydroxy ketones are a type of aldol.
It is an α-hydroxyketone, also called a ketol, and is the simplest hydroxy ketone structure. It is a colorless, distillable liquid. It is a colorless, distillable liquid. Preparation
The net reaction between an aldehyde (or an alpha-hydroxy-ketone) and the copper(II) ions in Benedict's solution may be written as: RCHO + 2 Cu 2+ + 5 OH − → RCOO − + Cu 2 O + 3 H 2 O. The hydroxide ions in the equation forms when sodium carbonate dissolves in water. With the citrate included, the reaction becomes:
The following examples represent only a small portion of syntheses that highlight the use of the Rubottom oxidation to install an important α-hydroxy functionality. Some of the major features of the following syntheses include the use of buffered conditions to protect sensitive substrates and the diastereoselective installation of the α ...
Alpha hydroxy carboxylic acids, or α-hydroxy carboxylic acids (AHAs), are a group of carboxylic acids featuring a hydroxy group located one carbon atom away from the acid group. This structural aspect distinguishes them from beta hydroxy acids , where the functional groups are separated by two carbon atoms. [ 1 ]
The name combines the suffix 'ol' from the alcohol and the prefix depending on the carbonyl group, either 'ald' for an aldehyde, or 'ket' for a ketone, in which case it referred to as a 'ketol'. An aldol may also use the term β-hydroxy aldehyde (or β-hydroxy ketone for a ketol). The term "aldol" may refer to 3-hydroxybutanal. [1] [2]