Organic Stereochemistry. Part 8

This review terminates our general presentation of the principles of stereochemistry with special reference to the biomedicinal sciences. Here, we discuss and illustrate the principles of prostereoisomerism, and apply these to product and substrate? product stereoselectivity in drug metabolism. The review begins with an overview of the concept of prostereoisomerism, discussing such aspects as homotopic, enantiotopic, and diastereotopic groups and faces. The main part of this review is dedicated to drug and xenobiotic metabolism. Here, the concept of prostereoisomerism proves particularly helpful to avoid confusing metabolic reactions in which an existing stereogenic element (e.g., a stereogenic center) influences the course of the reaction (substrate stereoselectivity), with metabolic reactions which create a stereogenic element (almost always a stereogenic center; product stereoselectivity). Specifically, examples of product stereoselectivity will be taken from functionalization reactions (so‐called phase‐I reactions) and conjugation (so‐called phase‐II reactions). Cases where stereoisomeric substrates show distinct product stereoselectivities (substrate? product stereoselectivity) will also be presented.