AM1 calculational and experimental evidence that a -nitroxyl group significantly enhances the thermodynamic and kinetic acidities of ketones

The kinetics of NaOD-catalysed H/D exchange of 3,3,5,5-tetramethylcyclohexanone (1), 1-hydroxy-4-oxo-2,2,6,6-tetrame-thylpiperidine (2), 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl (3), 9-hydroxynorpseudopelletierine (4), and norpseudopelle-tierine-9-oxyl (5) have been studied in 60:40 dioxane–D 2 O(v/v) at 25.0 °C. The second-order rate constants are 9.20 × 10 −3 , 6.39 × 10 −2 , 1.59, 2.20 × 10 −2 , and 5.67 × 10 −1 L mol −1 s −1 for 1, 2, 3, …