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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."
Examples of absolute configuration of some carbohydrates and amino acids according to Fischer projection (D/L system) and Cahn–Ingold–Prelog priority rules (R/S system) The R/S system is an important nomenclature system for denoting enantiomers. This approach labels each chiral center R or S according to a system by which its substituents ...
There are three common naming conventions for specifying one of the two enantiomers (the absolute configuration) of a given chiral molecule: the R/S system is based on the geometry of the molecule; the (+)- and (−)- system (also written using the obsolete equivalents d- and l-) is based on its optical rotation properties; and the D/L system is based on the molecule's relationship to ...
In chemistry, a racemic mixture or racemate (/ r eɪ ˈ s iː m eɪ t, r ə-, ˈ r æ s ɪ m eɪ t / [1]) is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates.
(P-P= (R)-BINAP, X= Cl, H, H2, or solvent) The steric bulk of the BINAP ligand coupled with the coordination of ruthenium to the carbonyl oxygen atoms results in high selectivity for hydrogen insertion on one face. This resulting stereochemistry of (R,S) and (R,R) is obtained in 94.5% yield while the other three stereoisomers range from 0.5-3% ...
As indicated earlier, the (R)- enantiomer is the pharmacologically active diuretic. Like most other diuretics, the (R)-isomer possesses an undesirable side-effect of retaining uric acid. But the (S)-enantiomer, the distomer , has the property of assisting uric acid secretion (uricosuric effect), and, therefore, antagonizing the undesirable side ...
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The unforeseen teratogenicity of the (R)-(+)-isomer caused it to become an important case study of stereochemistry in medicine. Although it is possible to chemically isolate just the desired (S)-(−)-isomer from the racemic mixture, the two enantiomers rapidly interconvert in vivo; thus rendering their separation to be of little use. [14]