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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."
President Herbert Hoover's newly created United States law enforcement and observance commission (circa. 1920). The National Commission on Law Observance and Enforcement (also known unofficially as the Wickersham Commission) was a committee established by the U.S. president, Herbert Hoover, on May 20, 1929.
Selective enforcement has become a topic of great discussion in the illegal immigration debate. The 2011 "Morton Memo" [7] laid out enforcement priorities for the U.S. Immigration and Customs Enforcement, and was intended to channel limited resources into prioritized pursuit of cases involving criminals and felons. It was interpreted as the ...
Stereoconvergence can be considered an opposite of stereospecificity, when the reaction of two different stereoisomers yield a single product stereoisomer. The quality of stereoselectivity is concerned solely with the products, and their stereochemistry. Of a number of possible stereoisomeric products, the reaction selects one or two to be formed.
The Cram's rule of asymmetric induction named after Donald J. Cram states In certain non-catalytic reactions that diastereomer will predominate, which could be formed by the approach of the entering group from the least hindered side when the rotational conformation of the C-C bond is such that the double bond is flanked by the two least bulky groups attached to the adjacent asymmetric center. [3]
The code is one example of police corruption and misconduct. Officers who engaged in discriminatory arrests, physical or verbal harassment, and selective enforcement of the law are considered to be corrupt, while officers who follow the code may participate in some of these acts during their careers for personal matters or in order to protect or support fellow officers. [5]
Enantioselective ketone reductions convert prochiral ketones into chiral, non-racemic alcohols and are used heavily for the synthesis of stereodefined alcohols. [1]Carbonyl reduction, the net addition of H 2 across a carbon-oxygen double bond, is an important way to prepare alcohols.
An autocatalytic reaction, a reaction in which the product acts as a catalyst for itself, serves as a model for homochirality. The asymmetric Soai reaction is commonly referred to as chemical plausibility for this pre-biotic hypothesis. In this system, an asymmetric amplification is observed during the process of autocatalytic catalysis.