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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."
The Schöllkopf method or Schöllkopf Bis-Lactim Amino Acid Synthesis is a method in organic chemistry for the asymmetric synthesis of chiral amino acids. [1] [2] The method was established in 1981 by Ulrich Schöllkopf. [3] [4] [5] In it glycine is a substrate, valine a chiral auxiliary and the reaction taking place an alkylation.
Chiral auxiliaries are incorporated into synthetic routes to control the absolute configuration of stereogenic centers. David A. Evans' synthesis of the macrolide cytovaricin, considered a classic, utilizes oxazolidinone chiral auxiliaries for one asymmetric alkylation reaction and four asymmetric aldol reactions, setting the absolute stereochemistry of nine stereocenters.
Chiral technology is an active subject matter related to asymmetric synthesis [18] and enantioselective analysis, particularly in the area of chiral chromatography. As a consequence of the advances in chiral technology, a number of pharmaceuticals currently marketed as racemic drugs are undergoing re-assessment as chiral specific products or ...
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]
Diisopinocampheylborane is an organoborane that is useful for asymmetric synthesis. This colourless solid is the precursor to a range of related reagents. The compound was reported in 1961 by Zweifel and Brown in a pioneering demonstration of asymmetric synthesis using boranes. The reagent is mainly used for the synthesis of chiral secondary ...
(R)-α-methoxy-α-(trifluoromethyl)- phenylacetic acid (Mosher's acid). In analytical chemistry, a chiral derivatizing agent (CDA), also known as a chiral resolving reagent, is a derivatization reagent that is a chiral auxiliary used to convert a mixture of enantiomers into diastereomers in order to analyze the quantities of each enantiomer present and determine the optical purity of a sample.
Such chiral diols are important in organic synthesis. The introduction of chirality into nonchiral reactants through usage of chiral catalysts is an important concept in organic synthesis . This reaction was developed principally by K. Barry Sharpless building on the already known racemic Upjohn dihydroxylation , for which he was awarded a ...