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Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer.

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Presentation on theme: "Stereoisomer Descriptor. Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer."— Presentation transcript:

1 Stereoisomer Descriptor

2 Stereoisomer Enantiomer Enantiomer Diastereomer Diastereomer Erythro, threo Erythro, threo Meso Compound Meso Compound Epimer Epimer ChiralMolecules With No Chiral Centers Chiral Molecules With No Chiral Centers

3 Definitions Stereoisomers – compounds with the same connectivity, different arrangement in space Stereoisomers – compounds with the same connectivity, different arrangement in space Enantiomers – stereoisomers that are non- superimposible mirror images; only properties that differ are direction (+ or -) of optical rotation Enantiomers – stereoisomers that are non- superimposible mirror images; only properties that differ are direction (+ or -) of optical rotation Diastereomers – stereoisomers that are not mirror images; different compounds with different physical properties Diastereomers – stereoisomers that are not mirror images; different compounds with different physical properties

4 enantiomer

5 Erythro dan threo

6 Diastereomer: Stereoisomer yang bukan pasangan enantiomer 1 dan 2 enantiomer 3 dan 4 juga enantiomer Diastereomer: 1-3; 1-4; 2-3 dan 2-4

7 Epimers: distereomer yang berbeda hanya pada satu pusat kiral saja

8 Senyawa meso

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11 ChiralMolecules With No Chiral Centers Allenes can be Chiral Chiral Molecules With No Chiral Centers Allenes can be Chiral

12 Mycomycin, an antibiotic

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15 Specifying Configuration (Chirality); Cahn-Ingold-Prelog Notation Specifies the "configuration" at each chiral center, equivalent to "cis-" and "trans-" etc. Abbreviated rules Assign priorities to groups attached to chiral center according to atomic # (same as Z/E rules) Compare 2nd, 3rd etc. atom from center as necessary, look for first point of difference Multiple bonds "add up" Determine direction of rotation 1 > 2 > 3 looking with #4 group pointing "away"

16 Prioritize Using Cahn-Ingold-Prelog Rules Look at atoms directly attached to chirality center a) higher atomic number = higher priority b) heavier isotopes = higher priority If no difference at first attached atom, move along the chain until the first point of difference. Multiple-bonded atoms are equivalent to the same number of single-bonded atoms.


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