Active role of hydrogen bond and ambient water in Meyer-Schuster rearrangements in high-temperature water

Meyer-Schuster rearrangements of 2-phenyl-3-butyn-2-ol with H ₃O ⁺ and (H ₂O) ₆ model in high-temperature water (HTW) have been investigated by the use of density functional theory calculations. In the substrate 2-phenyl-3-butyn-2-ol catalyzed by H ₃O ⁺ and (H ₂O) ₆, the Meyer-Schuster rearrangements were predicted by the frontier molecular orbital theory. The results show that the rearrangement does not involve the carbonium ion intermediates, but the first transition state is carboniumion like. Dehydration and hydration may occur via the intermolecular proton relay along the hydrogen-bond chains and the second step of reaction path is a total acid-base catalytic process. Based on the results, a model considered both HTW ambient and water molecules are proposed to represent mechanisms of other reactions in HTW.