Catalytic Bromide and Iodide Exchange of Alkyl Chlorides with HBr and HI

Article abstract of DOI:10.1021/jo00274a013

The need to develop efficient methods for the conversion of the generally cheaper, readily available alkyl chlorides to the more reactive, synthetically useful alkyl bromides and iodides is addressed by the use of gaseous HBr and HI in the presence of a ferric halide catalyst.The simple catalytic procedure is especially applicable to secondary and tertiary alkyl chlorides as well as vicinal dichlorides at ambient temperatures in aprotic solvents such as dichloromethane and carbon tetrachloride.The unique role of the FeBr3 catalyst to effect a reversible exchange of bromide via carbenium intermediates is discussed.