Electron-Beam-Induced Fries Rearrangement and Oxidation Reactions of Sulfonic Acid Esters in Crystalline State

Abstract

The electron beam (EB)-induced reactions of arylsulfonic acid esters, phenyl p-toluenesulfonate (1a), phenyl benzenesulfonate (1b), and phenyl 1-naphthalenesulfonate (1c), were examined in the balk state. The EB irradiation of 1a afforded the Fries rearrangement products, o- and p-hydroxyphenyl p-tolylsulfoes (2a and 3a), phenol (5) and the oxidation products of 2a, o,p-dihyroxyphenyl p-tolysulfon (4a), which has not been observed in photolysis. The EB-induced reaction of 1a exhibits higher ortho-regioselectivity at the early stage owing to crystal lattice control. The radiation of 1b, which is liquid at room temperature, give Fries rearrangement products with lower ortho/para regioselectivity. On the other hand, the EB-induced reaction of 1c proceeded with the lowest reactivity through crystal to crystal transformation to afford Fries rearrangement products, o- and p-hydroxyohenyl 1-naphthylsulfones (2c and 3c), and 5, but not oxidation product. The mechanistic study reveals that oxidation rpoduct 4a generated by the oxidation reaction of ortho-Fries rearrangement product 2a but not para-isomer 3a with an active oxidant, which should result from the decomposition of 1a.