Synthesis of Bromo‐Substituted 4‐Hydroxy[2.2]paracyclophanes and [2.2]Paracyclophane‐4,7‐quinones as Versatile Chiral Building Blocks

Approaches to a number of bromo‐substituted derivatives of 4‐hydroxy[2.2]paracyclophane, including the regioselective mono‐ and dibromination of this phenol, were investigated. The applicability of the regioisomeric monobromo‐substituted phenols for the synthesis of substituted [2.2]paracyclophane‐4,7‐quinones through a one‐pot diazonium coupling/reduction/oxidation sequence was demonstrated. The compounds obtained possess various substitution patterns and could be used for the synthesis of a wide range of [2.2]paracyclophane derivatives by transformation of the bromine, hydroxy, and quinoid fragments.