Kinetics and Mechanism of the Intramolecular Substitution of Acetate in 2′-Hydroxyphenacyl Acetate: 2′-Hydroxyphenacyl as a Potential Protective Group for Carboxylic Acids
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Kinetics and Mechanism of the Intramolecular Substitution of Acetate in 2′-Hydroxyphenacyl Acetate: 2′-Hydroxyphenacyl as a Potential Protective Group for Carboxylic Acids
2-Acetoxy-2′-hydroxyacetophenone (1c) undergoes cyclisation in water via its phenolate ion to release acetate and coumaran-3-one (2) at rates defined by the equation kobs = k1/[1+(10-pH)/Ka] where k1, the first order rate coefficient for the cyclisation of the phenolate ion, is 8.6 × 10−4 s−1 and Ka, the ionisation constant for 2′-OH is 2.0 × 10−9 (pKa 8.70) at 30°C.
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