Pyren‐2‐yl‐Substituted Biphenoquinone and p‐Benzoquinone: Pyren‐2‐yl as a Weak Electron‐Withdrawing Substituent

Abstract Pyren‐2‐yl‐substituted biphenoquinone and p ‐benzoquinone were designed and synthesized by oxidizing 2,6‐bis(pyren‐2‐yl)phenol with PbO 2 in acetic acid. The molecules showed properties characteristic of biphenoquinone and p ‐benzoquinone, i. e., reduction processes and light absorption in the visible region. In electrochemistry, the positively shifted reduction potentials suggest that pyren‐2‐yl could act as an electron‐withdrawing substituent although the substitution position of the pyrene is the node of its frontier orbital. The biphenoquinone derivative underwent the thermal reductive disproportionation reaction to afford corresponding hydroquinones and furan annulated π‐expanded compounds.