ABSTRACT

INTRODUCTION According to the International Union of Pure and Applied Chemistry (IUPAC) definition (1), stereoisomerism is a type of isomerism that arises from the differences in the spatial arrangement of atoms without any differences in connectivity or bond multiplicity between the isomers. One of the most important branches of stereochemistry is related to molecular dissymmetry and to the study of chiral molecules. The terminology used to describe stereochemical relationships is often a maze of interchangeable terms (capital D’s and L’s, lowercase d’s and l’s, mixed in with R’s, S’s, (þ)’s, and ()’s, to name a few). It is therefore appropriate to address basic stereochemical terms and concepts to lay a foundation for the more technical discussions that follow. This is not meant to be an in-depth treatment of this topic; there are many fine texts on the subject (2,3), which may be consulted if more detailed understanding is required. The chapter is the update to work previously published by I.W. Wainer and A.A. Marcotte in the 2nd edition of this book.