A Mild Procedure for the Preparation of Phenols from Polycyclic Aromatic Ketones

Abstract

Abstract A mild method is described for the preparation of phenols from polycyclic aromatic ketones. Ketones which have the carbonyl group adjacent to an aromatic ring can be converted to phenyl selenides by treatment with phenylselenenyl chloride in ethyl acetate at room temperature. Oxidation with 30% hydrogen peroxide in tetrahydrofuran at room temperature affords the corresponding phenols in generally high yield. Phenolic derivatives of phenanthrene, fluoranthene, benz[a]anthracene, and benzo[a]pyrene were prepared using this general procedure. Oxidation of the 2-phenylselenenyl derivative of 1,12c-dihydrobenzo[j]fluoranthene with 30% hydrogen peroxide resulted in anomalous formation of the 2,3-quinone instead of 3-hydroxybenzo[j]fluoranthene. The mildness and selectivity of the selenation-oxidation procedure was demonstrated by the aromatization of a cyclic ketone without concomitant dehydrogenation in a partially saturated ring. β-Tetralone reacted with phenylselenenyl chloride at room temperature to form a single compound in high yield identified as 2-naphthol. This reaction occurred in the absence of an added oxidizing agent. Another β-tetralone-type ketone, 1,2-dihydrophenanthren-3(4H)-one, was converted into 3-hydroxyphenanthrene under the same reaction conditions. Similar treatment of 1,10b-dihydrofluoranthen-2(3H)-one failed to yield either 2-hydroxyfluoranthene or the 2,3-quinone.