ABSTRACT
The injection of one electron into an organic halide, RX, by reaction with an electron donor in homogeneousconditionsaswellasbyelectrochemicalorothermeansgivesthefragmentationof themolecule,bybreakingthecarbon-halogenσbond.Forthisreason,suchaprocessisnamed dissociativeelectrontransfer(DET).Therearetwopossiblereactionmechanismsforthereductive cleavageofcarbon-halogenbonds(seeChapter14).Electrontransfer(ET)andbondbreakingcan occur either by a stepwise mechanism (Equations 24.1 and 24.2), with the intermediate formation of aradicalanionRX.−, or in a concerted way in which ET and bond fragmentation occur in a single step (Equation 24.3):
RX e RX+ − •− (24.1)
RX R X • •− → + − (24.2)
I. Introduction .......................................................................................................................... 917 II.Homogeneous Catalysis ........................................................................................................920
