Steric effects of nucleophile-radical coupling reaction. Determination of

TOMAS C. TEMPESTI; ADRIANA B. PIERINI; MARIA T. BAUMGARTNER

NEW JOURNAL OF CHEMISTRY

The Royal Society of Chemistry

Lugar: London; Año: 2009 p. 1523 - 1528

1144-0546

ABSTRACT. The absolute rate constants for the reaction of different aryl radicals with 2 - naphthoxide anion were determined using an indirect method, which is the competition of the coupling reaction with the H-atom abstraction. We here show that the radical-ambident nucleophile 10 reactions are sensitive to steric hindrance. A lower reactivity is found for 2-anisyl radical with respect to 4-anisyl and for 2-methoxy-1-naphtyl radical with respect to 1-naphthyl (k2b < k2a and k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. respect to 4-anisyl and for 2-methoxy-1-naphtyl radical with respect to 1-naphthyl (k2b < k2a and k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. respect to 4-anisyl and for 2-methoxy-1-naphtyl radical with respect to 1-naphthyl (k2b < k2a and k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. reactions are sensitive to steric hindrance. A lower reactivity is found for 2-anisyl radical with respect to 4-anisyl and for 2-methoxy-1-naphtyl radical with respect to 1-naphthyl (k2b < k2a and k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. 2b < k2a and k2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. in agreement with energy barriers determined by theoretical calculations. 2d < k2c). The ortho substitution to the radical centre decreases the rate constant. The reactivity is in agreement with energy barriers determined by theoretical calculations.