Bromination of hydrocarbons with CBr₄, initiated by light-emitting diode irradiation

The bromination of hydrocarbons with CBr₄ as a bromine source, induced by light-emitting diode (LED) irradiation, has been developed. Monobromides were synthesized with high efficiency without the need for any additives, catalysts, heating, or inert conditions. Action and absorption spectra suggest that CBr₄ absorbs light to give active species for the bromination. The generation of CHBr₃ was confirmed by NMR spectroscopy and GC-MS spectrometry analysis, indicating that the present bromination involves the homolytic cleavage of a C-Br bond in CBr₄ followed by radical abstraction of a hydrogen atom from a hydrocarbon.