Abstract: Pinacol mono-p-nitrobenzoate (POH) undergoes a rapid, reversible cyclization in base producing an anionic tetrahedral intermediate (TO-), the conjugate base of 2-(p- nitrophenyl)-2-hydroxy-4, 4, 5, 4-tetramethyl-1, 3-dioxolane (TOH). Presence of the anion is established by changes in UV spectra and by the rate behavior exhibited in the hydrolysis of the ester to pinacol and p-nitrobenzoate. Rate constants in base do not rise as rapidly as ...
