Hell-Volhard-Zelinsky Reaction

C. Hell, Ber. 14, 891 (1881); J. Volhard, Ann. 242, 141 (1887); N. Zelinsky, Ber. 20, 2026 (1887).

α-Halogenation of carboxylic acids in the presence of catalytic phosphorus, presumably involving the enol form of the intermediate acyl halide:



N. O. V. Sonntag, Chem. Rev. 52, 237 (1953); H. J. Harwood, ibid. 62, 102 (1962); H. Kwart, E. V. Scalzi, ibid. 86, 5496 (1964); A. R. Sexton et al., J. Am. Chem. Soc. 91, 7098 (1969); G. L. Lange, J. A. Otulakowski, J. Org. Chem. 47, 5093 (1982); R. J. Crawford, ibid. 48, 1364 (1983); H.-J. Liu, W. Luo, Synth. Commun. 21, 2097 (1991).