Homolytic Substitution at Furan and Thiophene: Rate Constants for the Formation and Decay of the Radical Intermediates

Article abstract of DOI:10.1021/jo00169a018

Absolute rate constants for radical addition to thiophene and furan have been measured by using kinetic EPR spectroscopy and laser flash photolysis.Additions of phenyl, diethoxyphosphonyl, and triethylsilyl radicals are rapid and have rate constants > 10⁶M^-1s^-1 at 25 deg C in hydrocarbon solvent.Comparison with data for the analogous reactions with benzene and 1-hexene shows that the heterocyclic compounds are generally less reactive than 1-hexene but are substantially more effective as radical scavengers than benzene.