(a)
Interpretation:
The way in which four stereoisomers arise for 3-penten-2-ol has to be explained.
Concept Introduction:
Alkene:
Geometric isomers: Two compounds are considered as geometric isomers of each other if both contain same number of atoms but different in their arrangement.
E configuration: The geometric isomers are given E configuration if high priority groups are placed on opposite sides of the double bond.
Z configuration: The geometric isomers are given Z configuration if high priority groups are placed on same sides of the double bond.
Chirality: It refers to a Carbon atom in a molecule that contains four different substituents.
According to Cahn-Ingold-Prelog system,
The group attached to asymmetric center should be ranked based on the
Check the direction of arrow drawn in the direction of decreasing priority. If the arrow points clockwise direction, then the atom has R configuration. If the arrow points counterclockwise direction, then the atom has S configuration. If the group with lowest priority is not bonded by a hatched wedge, then interchange this group (lowest priority) by group bonded to hatched wedge and draw the arrow in priority order but the configuration is assigned as just reverse.
(a)
Interpretation:
The stereoisomer having the E configuration at the carbon-carbon double bond and the R configuration at the chiral center has to be drawn.
Concept Introduction:
Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.
Geometric isomers: Two compounds are considered as geometric isomers of each other if both contain same number of atoms but different in their arrangement.
E configuration: The geometric isomers are given E configuration if high priority groups are placed on opposite sides of the double bond.
Z configuration: The geometric isomers are given Z configuration if high priority groups are placed on same sides of the double bond.
Chirality: It refers to a Carbon atom in a molecule that contains four different substituents.
According to Cahn-Ingold-Prelog system,
The group attached to asymmetric center should be ranked based on the atomic number of atom which directly connected to asymmetric center. The higher the atomic number of atom, higher the priority. If there is tie, then consider the next atoms attached to the connected atom and so on.
Check the direction of arrow drawn in the direction of decreasing priority. If the arrow points clockwise direction, then the atom has R configuration. If the arrow points counterclockwise direction, then the atom has S configuration. If the group with lowest priority is not bonded by a hatched wedge, then interchange this group (lowest priority) by group bonded to hatched wedge and draw the arrow in priority order but the configuration is assigned as just reverse.
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Chapter 5 Solutions
Organic Chemistry
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