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An enantioselective reaction is one in which one enantiomer is formed in preference to the other, in a reaction that creates an optically active product from an achiral starting material, using either a chiral catalyst, an enzyme or a chiral reagent. The degree of selectivity is measured by the enantiomeric excess.
Enantioselective synthesis, also called asymmetric synthesis, [1] is a form of chemical synthesis.It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in unequal amounts."
The Sharpless epoxidation is viable with a large range of primary and secondary alkenic alcohols. Furthermore, with the exception noted above, a given dialkyl tartrate will preferentially add to the same face independent of the substitution on the alkene.To demonstrate the synthetic utility of the Sharpless epoxidation, the Sharpless group created synthetic intermediates of various natural ...
The enantioselective oxidation of unsymmetrical thioethers to sulfoxides is a well established. [6] The common over the counter medication Esomeprazole (brandname: Nexium) involves such an asymmetric oxidation as its final step. [7] Even disulfides are susceptible to oxidation to chiral thiosulfinites. [8]
Asymmetric versions of the above reaction have taken advantage of a number of strategies for achieving asymmetric induction. The highest yielding and most enantioselective methods include: Use of stoichiometric chiral oxidant [5] Use of stoichiometric metal peroxides substituted with chiral ligands [6] Use of stoichiometric chiral base [7]
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Many circuit courts have said that law enforcement can hold your property for as long as they want. D.C.’s high court decided last week that’s unconstitutional.
In law, selective enforcement occurs when government officials (such as police officers, prosecutors, or regulators) exercise discretion, which is the power to choose whether or how to punish a person who has violated the law. The biased use of enforcement discretion, such as that based on racial prejudice or corruption, is usually considered a ...