Problems

 

1. The molecule given below is menthol with the stereochemistry omitted.

 

1. Identify all stereocenters in menthol.
   
   
2. How many stereoisomers exist for the menthol structure?
   
   
3. Draw all the stereoisomers of menthol, and identify all pairs of enantiomers.
   
   
4. Natural (-)-menthol, the essential oil primarily responsible for the flavour and aroma of peppermint, is the 1 R ,2 S ,5 R -stereoisomer. Identify (+)-menthol from the structures.
   
   
5. Another of the naturally occurring diastereomers of menthol is (+)-isomenthol, the 1 S ,2 R ,5 R -stereoisomer. Identify (+)-isomenthol among your structures.
   
   
6. A third is (+)-neomenthol, the 1 S ,2 S ,5 R -compound. Find (+)-neomenthol among your structures.
   
   
7. What is the stability order (from most stable to least) for the three diastereomers, menthol, isomenthol and neomenthol?

 

Text Books

 

•  P. Y. Bruce and K J R. Prasad, Essential Organic Chemistry , Pearson Education, New Delhi, 2008.

•  C. M. Loudon , Organic Chemistry , Oxford University Press, New Delhi, 2002.