4.1. Preamble – Stereochemistry and Other Textbooks

Stereochemistry is a very complex topic that requires a high degree of practice and dedication to master. Many chemists find it genuinely beautiful, natural complexity, geometries, and patterns that can influence the world in profound ways.

Most important molecules in nature (amino acids, nucleotides, sugars, etc.) possess complex stereochemistry. As a result, pharmaceuticals (and anything else designed to affect biology) must be designed for an environment where exact three-dimensional shape is important for proper function. How one can do this is incredibly interesting, but can rapidly become incredibly complicated. When working through this chapter keep in mind that this is meant only as a foundation covering the fundamentals of stereochemistry; the field of stereochemistry is far too complex and varied to be covered in-depth in any introductory course.

All introductory organic chemistry courses teach the basics of stereochemistry. However, as our understanding of stereochemistry has evolved our terminology has evolved with it. Despite this, the vast majority of sources continue to use outdated, misleading, or in some cases outright incorrect terminology and definitions. This text will heavily discourage their use, emphasizing newer/correct terminology and definitions.

Stereochemistry is often especially challenging for new students. For many the largest issue is visualizing three-dimensional geometries from two-dimensional images. Physical models (molecular model kits) and computer images can be helpful, especially when first becoming familiar with a stereochemical concept. However, it is very important to remember that in the overwhelming majority of cases only simple wedges and hashes are given in drawings. Students should become as familiar with the concepts, geometries, and approaches to internal visualization as possible; a significant amount of practice is usually required to be comfortable when discussing stereochemistry in later chapters.