Verdazyl Radicals as Substrates for Organic Synthesis: The Synthesis and Characterization of [12]‐, [13]‐, and [21]‐Paraheteraphanes

A tandem intermolecular–intramolecular 1,3‐dipolar cycloaddition sequence with the bis‐azomethine imine derived from a para ‐aryl‐substituted bis‐verdazyl radical has been used to form a series of [ n ]‐paraheteraphanes, which form exclusively by a [1+1] double cycloaddition reaction, with no evidence for the formation of the [2+2] quadruple cycloadduct products. 1 H NMR spectroscopic studies show that rotation of the phenyl ring of these compounds is affected by the size and structure of the [ n ]‐paraheteraphane cavity.