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Le Bel-van't Hoff rule states that for a structure with n asymmetric carbon atoms, there is a maximum of 2 n different stereoisomers possible. As an example, D-glucose is an aldohexose and has the formula C 6 H 12 O 6. Four of its six carbon atoms are stereogenic, which means D-glucose is one of 2 4 =16 possible stereoisomers. [20] [21]
There are eight stereoisomers of cocaine (excluding mesomers and modifications to the internal portion of the tropane ring). [d] Due to the presence of four asymmetric carbon atoms in the 1- & 5- to 8 (N) position bond bridge that could adopt R-& S-configurations, cocaine can be considered to have as many as sixteen stereoisomers. However ...
Discounting isomers that are equivalent under rotations, there are nine isomers that differ by this criterion, and behave as different stable substances (two of them being enantiomers of each other). The most common one in nature ( myo -inositol) has the hydroxyls on carbons 1, 2, 3 and 5 on the same side of that plane, and can therefore be ...
A molecule having multiple stereocenters will produce many possible stereoisomers. In compounds whose stereoisomerism is due to tetrahedral (sp 3) stereogenic centers, the total number of hypothetically possible stereoisomers will not exceed 2 n, where n is the number of tetrahedral stereocenters. However, this is an upper bound because ...
There are many more pairs of diastereomers, because each of these configurations is a diastereomer with respect to every other configuration excluding its own enantiomer (for example, R,R,R is a diastereomer of R,R,S; R,S,R; and R,S,S). For n = 4, there are sixteen stereoisomers, or
Besides the 2-ketoses, there are only the 3-Ketoses, and they do not exist in nature, although at least one 3-ketohexose has been synthesized, with great difficulty. In the linear form, the 2-ketohexoses have three chiral centers and therefore eight possible stereoisomers (2 3 ), comprising four pairs of enantiomers.
The second case studied here is of 3-methylfentanyl. There are two potential stereocenters, at the 4-carbon and also at the 3-carbon, where there is additionally a methyl group. Now, we mark both 3 and 4 carbon as potential stereocenters with an asterisk (*), and see how many potential stereoisomers we can eliminate.
In stereochemistry, an asymmetric carbon is a carbon atom that is bonded to four different types of atoms or groups of atoms. [1] [2] The four atoms and/or groups attached to the carbon atom can be arranged in space in two different ways that are mirror images of each other, and which lead to so-called left-handed and right-handed versions (stereoisomers) of the same molecule.