Abstract:

DFT studies were carried out in order to investigate the epimerization of 2-benzyl-2-ethyoxyl-carbonyl-cyclopentanol in etherified reaction. Stationary structures and energy were obtained at the B3LYP/6-311+G(d,p) level. The loop will open when 2-benzyl-2-ethoxycarbonyl-cyclopentanol lose a H⁺, the —C—O^- group will turn into a aldehyde group, and the other carbon atom and the carbonyl composite a conjugate negative center. The energy of the trans conformation of the anion is 757 kJ/mol lower than the cis conformation, and the energy barrier of the conformation invert is only 305 kJ/mol. It shows the conformation invert reaction is controlled by thermodynamics and will happen easily. The result can explain the epimerization of 2-benzyl-2-ethoxycarbonyl-cyclopentanol in Williamson ether synthesis.

Key words: 2-Benzyl-2-ethoxycarbonyl-cyclopentanol; Epimerization; Williamson ether synthesis; Density functional theory(DFT)