Novel 1,4,5,8‐Phenanthrenediquinones and Unusual Deoxygenation with Trimethylsilyl Iodide

Abstract Attempt for aryl methyl ether cleavage of 5,8‐dimethoxy‐1,4‐phenanthrenequinone ( 4 ) with boron trichloride or tribromide resulted in the halogenation of the quinone double bond to form 5a , b . Surprisingly, reaction of dimethyl ether 4 with trimethylsilyl iodide afforded the phenanthrenediquinone 6 , whereas deoxygenation to 8 and 9 occurred by reaction of trimethylsilyl iodide with derivative 7 . The phenanthrenediquinones 6 and 10 were obtained nearly quantitatively from 4 and 7 by using ceric ammonium nitrate as the oxidant. The cyclic voltammograms of the phenanthrenediquinones 6 and 10 were studied and rationalized by Hückel Molecular Orbital calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)