Synthesis of Helical Quinone Derivatives by Oxidative Coupling of Substituted 2-Hydroxybenzo[c]phenanthrenes

A concise synthesis of novel substituted quinone derivatives from commercially available starting materials was developed. For this synthesis, classical photo-induced 6-electrocyclization was utilized, followed by oxidative aromatization reaction, and subsequent oxidative coupling reactions in the presence of CuCl(OH)-TMEDA. The unique quinone derivatives were characterized by IR, H-1, and C-13 NMR spectroscopies, and mass spectroscopic data analysis. In some cases, the keto dimers were obtained as significant intermediates for the quinone synthesis.