Intra‐ und extraannular funktionalisierte [2.2.2]Phane mit Dreifachbindung: Synthese und Eigenschaften

Intra‐ and Extraannularly Functionalized [2.2.2]Phanes: Syntheses and Properties The severely strained new cyclophanes 7b – f , consisting of bridged tolane subunits and bearing intraannular substituents R, were prepared mainly to study steric interactions of R with the “π cloud” of the triple bond. These compounds exist in a rigid twisted conformation, whereas the unsubstituted reference compound 7a and the extraannularly functionalized azo compound 9 show C 2 symmetry. 9 forms a 1 : 1 clathrate with toluene.