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Chirality (chemistry) Two enantiomers of a generic amino acid that are chiral. (S)-Alanine (left) and (R)-alanine (right) in zwitterionic form at neutral pH. In chemistry, a molecule or ion is called chiral (/ ˈkaɪrəl /) if it cannot be superposed on its mirror image by any combination of rotations, translations, and some conformational changes.
Chiral media. Chirality with hands and two enantiomers of a generic amino acid. The direction of current flow and induced magnetic flux follow a "handness" relationship. The term chiral / ˈkaɪrəl / describes an object, especially a molecule, which has or produces a non-superposable mirror image of itself. In chemistry, such a molecule is ...
Chirality(/kaɪˈrælɪti/) is a property of asymmetryimportant in several branches of science. The word chiralityis derived from the Greekχείρ(kheir), "hand", a familiar chiral object. An object or a system is chiralif it is distinguishable from its mirror image; that is, it cannot be superposed(not to be confused with superimposed) onto it.
For example, amines with three distinct substituents are chiral, but with few exceptions (e.g. substituted N-chloroaziridines), they rapidly undergo "umbrella inversion" at room temperature, leading to racemization. If the racemization is fast enough, the molecule can often be treated as an achiral, averaged structure.
The "D-" and "L-" prefixes are used to specify the enantiomer of chiral organic compounds in biochemistry and are based on the compound's absolute configuration relative to (+)-glyceraldehyde, which is the D-form by definition. The prefix used to indicate absolute configuration is not directly related to the (+) or (−) prefix used to indicate ...
Chiral auxiliary. In stereochemistry, a chiral auxiliary is a stereogenic group or unit that is temporarily incorporated into an organic compound in order to control the stereochemical outcome of the synthesis. [1][2] The chirality present in the auxiliary can bias the stereoselectivity of one or more subsequent reactions.
Racemic mixture. In chemistry, a racemic mixture or racemate (/ reɪˈsiːmeɪt, rə -, ˈræsɪmeɪt / [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.
The chiral-altering ligands employed for synthesizing these acids often have multiple Lewis basic sites (often a diol or a dinitrogen structure) that allow the formation of a ring structure involving the metal atom. [1] [2] Achiral Lewis acids have been used for decades to promote the synthesis of racemic mixtures in myriad different reactions ...