When determining the R and S configuration of a molecule, what does clockwise represent?

When determining the R and S configuration of a molecule, what does clockwise represent?

• A. S
• B. R
• C. Neither
• D. Both

Answer: (B)

In the context of determining the stereochemistry of a molecule using the Cahn-Ingold-Prelog priority rules, clockwise representation indicates an R configuration. This is established through the assignment of priorities to the substituents attached to the chiral center. When the lowest priority group (often the one with the lowest atomic number) is placed at the back of the configuration (pointing away from the viewer), if the sequence of the remaining groups is observed to progress in a clockwise direction, the chiral center is designated as having an R configuration. Therefore, recognizing how to interpret the orientation of substituents and understanding that clockwise arrangement corresponds to R is crucial for accurately assigning stereochemical configurations.

In the context of determining the stereochemistry of a molecule using the Cahn-Ingold-Prelog priority rules, clockwise representation indicates an R configuration. This is established through the assignment of priorities to the substituents attached to the chiral center.

When the lowest priority group (often the one with the lowest atomic number) is placed at the back of the configuration (pointing away from the viewer), if the sequence of the remaining groups is observed to progress in a clockwise direction, the chiral center is designated as having an R configuration.

Therefore, recognizing how to interpret the orientation of substituents and understanding that clockwise arrangement corresponds to R is crucial for accurately assigning stereochemical configurations.