Biocatalyzed desymmetrization of meso-diols has recently emerged as a powerful strategy for chiral synthesis. The products of this reaction have defined chirality and are suitable intermediates for the synthesis of biologically active compounds. Desymmetrization of meso compounds with organocatalysts is an important step in natural product synthesis.
The asymmetric Pauson-Khand catalysts have been used in the desymmetrization of meso dienynes. The process also produces the enantioenriched bromocycloalkenes. The enantioenriched bromocycloalkene products are obtained via asymmetric allylic substitution. These products are widely used in synthesis.
Stereochemistry of meso compounds
The stereochemistry of meso compounds refers to the property of having two or more chiral centers on the same molecule. These stereocenters are connected by an internal symmetry plane, which divides the compound into two halves. The stereochemistry of each side of the compound should cancel out, with the left side having the opposite stereochemistry of the right side. Therefore, meso compounds do not display optical activity.
This symmetry plane does not appear immediately, so identifying meso compounds involves recognizing molecules drawn in different projections, observing the rotations of their chiral centers, and using the (R)/(S) designations. There are two main strategies for meso compound identification. The first strategy is to identify the stereoisomer with its mirror image. The second strategy is to determine which is the chiral carbon on the left-hand side of the molecule.
Isomerism in meso compounds
Meso compounds are two-dimensional organic molecules that have one or more stereocenters. The two chiral centers share the same substituents, making the molecule meso. The symmetry plane of a meso compound leads to the mirror image of the other meso compound. This is how meso compounds are classified. These types of compounds can be cyclic, achiral, or diatomic.
Isomerism in meso compounds is a property of many cyclic compounds. These enantiomers have the same atomic arrangements but differ in their chirality. Hence, stereoisomers are classified as achiral and cis enantiomers. In case of diatomic cyclohexanes, for example, the cis enantiomer behaves as a meso compound. In the presence of chiral reagents, however, the stereoisomers behave similarly.
Identification of meso compounds
Unlike ordinary molecules, meso compounds have an internal mirror plane, or plane of symmetry. This plane divides the compound into two parts, the left and the right, and acts like an internal mirror. The stereochemistry of the two halves should cancel each other out, or they should be mirrored, which results in optical inactivity. To identify meso compounds, you can use an internal mirror. Aside from using an internal mirror, you can use a chiral center diagram to help you identify these compounds.
Meso compounds are cyclic compounds that have two or more chiral centres. This symmetry plane gives them the ability to superimpose their mirror images. A typical example of a meso compound is tartaric acid, which is achiral and cis-stackable. Another example of a meso compound is cis-1,2-dichlorocyclohexane, which is the opposite of its trans-stackable form.
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