Counterattack Reagents Sodium Trimethylsilanethiolate and Hexamethyldisilathiane in the Bis-O-demethylation of Aryl Methyl Ethers

Article abstract of DOI:10.1021/jo00311a016

New methods were developed for removal of two methyl groups from aryl methyl ethers.Treatment of an aryl methyl ether containing two methoxy units (i. e., 1, 3, 5, 7, 9, 11, or 13) with ca. 2.5 equiv of Me3SiSNa in 1,3-dimethyl-2-imidazolidinone at 185 deg C in a sealed tube gave the corresponding aryl alcohol (i. e. 2, 4, 6, 8, 10, 12 or 14) in 78-96percent yields after aqueous workup.Also, Me3SiSSiMe3 was found useful for bis-O-demethylation of aromatic compounds containing one free hydroxyl group and two methoxy units (e. g., 11 and 13).Thus 11 and 13 reacted with 1.5 equiv of NaH and then with 1.5 equiv of Me3SiSSiMe3 at 185 deg C in a sealed tube to afford triols 13 (75percent) and 14 (72percent), respectively.In these bis-O-demethylations, Me3SiSNa and Me3SiSSiMe3 act as counterattack reagents.