Observation of a stable hemiortho ester anion. Acidity constant for a tetrahedral intermediate

RA McClelland, NE Seaman…

Index: McClelland, Robert A.; Seaman, N. Esther; Cramm, David Journal of the American Chemical Society, 1984 , vol. 106, # 16 p. 4511 - 4515

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Citation Number: 11

Abstract

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 ...