Phenanthrene-4,5-quinones: a synthesis of morphenol

Abstract

Oxidation of 1,3,6,8-tetra-t-butyl-9,10-dihydrophenanthrene-4,5-diol (8), gave the corresponding 4,5-quinone (9), isolated as its oxepine valence isomer (19). Oxidation of 1,3,6,8-tetra-t-butylphenanthrene-4,5-diol (3) gave an even less stable quinone (4) which rearranged via its arene oxide valence isomer (26) to an enone (22). Acid-catalysed debutylation of this produced morphenol (24). The annelated analogue (27) of the phenanthrenequinone (4) showed no tendency to rearrange.