Nonconjugated Hydrocarbons as Rigid-Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

Nonconjugated hydrocarbons, like bicyclo[1.1.1]-pentane, bicyclo[2.2.2]octane, triptycene, and cubane are a unique class of rigid linkers. Due to their similarity in size and shape they are useful mimics of classic benzene moieties in drugs, so-called bioisosteres. Moreover, they also fulfill an important role in material sciences as linear linkers, in order to arrange various functionalities in a defined spatial manner. In this Review article, recent developments and usages of these special, rectilinear systems are discussed. Furthermore, we focus on covalently linked, nonconjugated linear arrangements and discuss the physical and chemical properties and differences of individual linkers, as well as their application in material and medicinal sciences.