Aryl Halide Radical Clocks as Probes of Stannylene/Aryl Halide C–H Activation Rates

Using the radical cyclization induced by the reaction of ( 1 ) with 1-(but-3-en-1-yloxy)-2-iodobenzene, we have determined the rate of allylic and propargylic C–H activation to be 1.1 ± 0.2 × 10 8 M −1 s −1 . The rate of oxidative addition of aryl halide with 1 was estimated to be 10 7 –10 8 M −1 s −1 . The radical cyclization involving 1 and 1-(allyloxy)-2-iodobenzene proceeds quantitatively, indicating that the rate of cyclization (9.6 × 10 9 s −1 ) is faster than the rate of hydrocarbon/alkene/alkyne C–H abstraction.