.R/S-E/Z Configuration Exercises

Select a compound from the black panel. It will appear in the white panel. In the examples under "Several Chiral Centers", the numbers in brackets indicate the number of chiral centers. Determine the R/S-configuration of each chiral center and the E/Z-configuration of the double bonds. Gold buttons have E/Z double bond configurations in addition to R/S chiral centers. Click the "show R/S" or "show E/Z" button to check your answer and display any comments (Notes:). Atom Colors: carbon, gray; hydrogen, light blue; bromine, magenta; chlorine, green; nitrogen, blue; oxygen, red; sulfur, yellow. Notice: Atom numbers (hovering) may not agree with nomenclature numbers. Read How to Manipulate JSmol Structures to move structures if you use the clockwise vs. counterclockwise method to determine R/S configuration. There is a better (hand) method discussed in a primer on R/S-configuration. The double bonds in some substituted benzenoid rings will have different E/Z designations depending upon which canonical resonance structure is shown. These designations have no meaning in delocalized structures.