Rate Constants and Arrhenius Functions for Ring Opening of a Cyclobutylcarbinyl Radical Clock and for Hydrogen Atom Transfer From the Et3B−MeOH Complex

Abstract

Kinetics of ring opening of the 1-cyclobutyldodecyl radical (1) were studied, and an Arrhenius function over the temperature range -20 to 47 degrees C was determined. The radical clock reaction has kinetics described by log k = 13.2 - 13.5/2.313 RT (in kcal/mol), and k = 1.5 x 10(3) s(-1) at 20 degrees C. Previous kinetic studies of hydrogen atom transfer trapping of radical 1 by the triethylborane-methanol complex at variable temperatures (J. Org. Chem. 2007, 72, 5098) were analyzed with the newly obtained kinetic data.