P. Evans, T. Brandt
Aug 8, 1997
Citations
0
Influential Citations
43
Citations
Journal
Journal of Organic Chemistry
Abstract
Treatment of 1,4-dimethoxynaphthalenes with iodosobenzene diacetate and trimethylsilyl chloride or bromide furnished the haloacetoxylated, acetoxylated, and halogenated 1,4-dimethoxynaphthalenes in excellent yield. The reaction pathway for each transformation was shown to be a function of reagent stoichiometry. A mechanistic hypothesis is presented that rationalizes the reaction pathways and explains the subtle differences in the halogenation reactions. The acetoxylation, for example, is thought to involve the formation of an iodonium ion that promotes the nucleophilic addition of acetate ion and subsequent 1,2-acetyl migration. Bromination occurs as a direct result of the oxidation of trimethylsilyl bromide to bromine, followed by electrophilic aromatic substitution. Chlorination is thought to proceed via a radical process and not the formation of molecular chlorine from the dissociation of iodosobenzene dichloride. The haloacetoxylation reaction also appears to be fairly specific for 1,4-dimethoxynaphth...