Dynamic Stereochemistry: A Simple Approach To Delineating Relative Configuration

摘要

The stereochemistry of reactions at a tetrahedral center in organic molecules primarily involves inversion or retention of configuration at that center. In this context, a simple approach is presented for delineating relative stereochemistry of the product in reactions involving stereogenic center(s). The configuration at a tetrahedral center is defined by a pair of ligands related by a clockwise (or counterclockwise) arc and a front (or rear) ligand. The arc is drawn through the tetrahedral angle taking the tetrahedral center as the geometric center. The inversion or retention of configuration is assigned by examining whether the clockwise–counterclockwise and front–rear relationships of two ligand pairs in the starting material are maintained or changed in the product. One change of such relationship would lead to inversion while retention involves either no change or changes of both the relationships. The method is illustrated with suitable examples.