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Since a meso isomer has a superposable mirror image, a compound with a total of n chiral centers cannot attain the theoretical maximum of 2 n stereoisomers if one of the stereoisomers is meso. [4] A meso isomer need not have a mirror plane. It may have an inversion or a rotoreflexion symmetry such as S 4. For example, there are two meso isomers ...
These include meso compounds, cis–trans isomers, E-Z isomers, and non-enantiomeric optical isomers. Diastereomers seldom have the same physical properties. In the example shown below, the meso form of tartaric acid forms a diastereomeric pair with both levo- and dextro-tartaric acids, which form an enantiomeric pair.
The achiral meso compound (1R,2S)-1,2-diphenyloxirane arises from cis-stilbene, though peroxide epoxidations of the cis-isomer produce both cis- and trans-epoxide products. For example, using tert-butyl hydroperoxide, oxidation of cis-stilbene produces 0.8% cis-stilbene oxide, 13.5% trans-stilbene oxide, and 6.1% benzaldehyde.
However, since all other isomers are meso (non-chiral) compounds, the name myo-inositol is now preferred (myo- being a medical prefix for "muscle"). Inositol was once considered a member of the vitamin B complex, namely vitamin B 8 before the discovery that it is made naturally in the human body, and therefore cannot be a vitamin or essential ...
A meso compound is superposable on its mirror image, therefore it reduces the number of stereoisomers predicted by the 2 n rule. This occurs because the molecule obtains a plane of symmetry that causes the molecule to rotate around the central carbon–carbon bond. [12] One example is meso-tartaric acid, in which (R,S) is the same as the (S,R) form
Isomers do not necessarily share similar chemical or physical properties. Two main forms of isomerism are structural (or constitutional) isomerism, in which bonds between the atoms differ; and stereoisomerism (or spatial isomerism), in which the bonds are the same but the relative positions of the atoms differ. Isomeric relationships form a ...
The compound exists as three stereoisomers, a pair of enantiomers and the meso isomer. All are colorless liquids. Preparation and reactions 2,3 ...
For example, when this probability is 0.25 then the probability of finding: an isotactic triad is P m 2, or 0.0625; an heterotactic triad is 2P m (1–P m), or 0.375; a syndiotactic triad is (1–P m) 2, or 0.5625; with a total probability of 1. Similar relationships with diads exist for tetrads. [5]: 357