Effect of Water on the Functionalization of Substituted Anisoles with Iodine in the Presence of F−TEDA−BF4 or Hydrogen Peroxide

Abstract

Water was found to be a convenient reaction medium for functionalization of substituted anisoles using iodine in the presence of Selectfluor F-TEDA-BF(4) or hydrogen peroxide as mediators and oxidizers. Two types of functionalization were observed: iodination or oxidation. In the iodination process, two reaction routes were established. In the case of the first route, a high iodine atom economy was achieved for selective and effective iodo functionalization with a stoichiometric ratio of substrate/iodine/(mediator/oxidizer) = 2:1:1.2. An electrophilic iodination reaction process was suggested for this route, with the oxidizer converting the liberated iodide anion to iodine. For the second reaction route, a stoichiometric ratio of substrate/iodine/(mediator/oxidizer) = 1:1:1 and a lower iodine atom economy were observed; in this case, ion radical formation in the first step of the reaction was suggested. Iodine was found to be an effective catalyst for the oxidation of a hydroxy benzyl functional group to benzaldehyde using F-TEDA-BF(4). Water is an effective medium for functionalization of anisole, p-methoxy benzyl alcohol, 1-(4-methoxyphenyl)ethanone, o-dimethoxy benzene, m-dimethoxy benzene, and p-dimethoxy benzene, whereas F-TEDA-BF(4) as a mediator/oxidizer could be replaced by hydrogen peroxide in the case of the functionalization of 1-(4-methoxyphenyl)ethanone, o-dimethoxy benzene, m-dimethoxy benzene, and p-dimethoxy benzene. Water changes the type of transformation of p-methoxy benzyl alcohol.