Strained Polycyclic Systems Consisting of Three‐ and Four‐Membered Rings

Polyclic compounds consisting of small rings have been known for several years. Their chemical and physical properties, which are of both theortical and practical interest, are discussed, and methods of preparation of a few examples are illustrated. The carbon skeletons of tetrahedrane, Dewar benzene, prismane, and cubane are discussed in greater detail, since the preparation of these compounds has now been achieved, or has at least been made possible.