Draw the structure of 1-ethyl-2-methylcyclopentane, creating specific stereogenic sites (i.e., use wedgedash at each site). Label each site as R or S. b) Draw the ENANTIOMER of your original molecule. Draw ONE DIASTEREOMER of your original molecule: H) Draw ONE CONSTITUTIONAL ISOMER of your original molecule and make it MESO. Name your MESO compound.
The correct Answer and Explanation is:
Here’s how the molecular design would look in terms of description:
- 1-Ethyl-2-Methylcyclopentane with Specific Stereogenic Sites:
- The molecule has a five-membered ring (cyclopentane) with an ethyl (-CH₂CH₃) group at position 1 and a methyl (-CH₃) group at position 2.
- If both carbon centers at positions 1 and 2 are chiral, we use wedge-dash notation to show the stereochemistry.
- Assigning R/S configurations depends on the priority of substituents based on the Cahn-Ingold-Prelog rules.
- Enantiomer of the Original Molecule:
- The enantiomer is the non-superimposable mirror image of the original molecule.
- It will have opposite configurations at all stereogenic centers (if both are R in the original, they would be S in the enantiomer).
- One Diastereomer:
- A diastereomer differs from the original molecule in at least one but not all stereogenic centers.
- If the original molecule has (R, R), one diastereomer could be (R, S) or (S, R), meaning only one stereocenter is flipped.
- One Constitutional Isomer (Meso Compound):
- A meso compound has chiral centers but is achiral overall due to an internal plane of symmetry.
- A possible meso form would be a different arrangement of ethyl and methyl groups where symmetrical stereochemistry cancels chirality.
- The meso form could be 1,3-dimethylcyclopentane, where each chiral center is opposite in configuration but symmetric.
Explanation:
Stereoisomers include enantiomers and diastereomers, which differ in spatial orientation of atoms. Enantiomers are mirror images, while diastereomers are non-mirror-image stereoisomers. Meso compounds, despite having chiral centers, are optically inactive because they possess an internal symmetry that negates optical rotation. Constitutional isomers, on the other hand, differ in connectivity rather than spatial arrangement.
