University Chemistry ›› 2017, Vol. 32 ›› Issue (3): 60-62.doi: 10.3866/PKU.DXHX201608016

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Descriptors for Stereoselectivity of Organic Reactions: %ee, %de or er, dr?

Zhuo CHAI*()   

  • Published:2017-03-15
  • Contact: Zhuo CHAI


The stereoselectivity of organic reactions and the stereoisomerism of organic compounds constitute one of the research topics with paramount importance not only in organic chemistry, but also in related disciplines such as medicinal science and life science. This article introduces the historic origins, connotations and academic usage contentions of several important descriptors for stereoselectivity and stereochemical purity:percent enantiomeric excess (%ee), percent diastereomeric excess (%de), enantiomeric ratio (er) and diastereomeric ratio (dr), and gives suggestion on introducing these terms in the teaching processes of relevant courses.

Key words: Stereoselectivity, Stereoisomerism, Enantioselectivity, Diastereoselectivity