Computational study of phenyliodine diacetate intermediates during Lewis acid activation with TMSOTf

Abstract

A method of increasing the reactivity of phenyliodine(III) diacetate (PIDA) involves the addition of a Lewis acid. The acid-activation of PIDA was investigated toward the goal of elucidating relevant intermediates that participate in other mechanisms such as the transmetallation of hypervalent iodine compounds with metalloids and diaryliodane synthesis. Our computational analysis focused on the reaction coordinate of PIDA reacting with TMSOTf. Acetate-triflate substitutions were found to be thermodynamically preferred over PIDA, and the possibility of a four-coordinate iodine intermediate is evaluated. Other structural and electronic considerations involving trans-influence, s-hole, and the 3-center-4-electron (3c-4e) bond are presented.