Control over stereogenic centres beyond tetracoordination

Abstract

In contrast to conventional tetracoordinate stereogenic centres exhibiting twofold stereogenicity, penta- and hexacoordinate stereogenic centres may encode more than two stereoisomers, expanding the stereochemical space accessible to these species. This more complex stereoisomerism is characteristic to compounds of a variety of main-group elements and transition metals having a suitable set of ligands. Despite these unique hallmarks and the prospective applications in medicinal chemistry, catalysis, and information science, this area of stereoselective synthesis awaits widespread exploration. In this review, the fundamentals of the higher-order stereogenicity of penta- and hexacoordinate stereogenic centres will thus be summarized and an overview of emerging applications and their stereoselective synthesis will be provided.