Features of 2-(2-hydroxy-5-chlorophenyl)-2-phenylethenyldiethylphosphine oxide bromination

Recently we obtained 2-aryl-2-(2-hydroxy-5-chlorophenyl)ethenylphosphine oxides (δ-hydroxylalkenylphosphine oxides) [1], interesting as extractants for the rare-earth metals [2]. Chemistry of these compounds, which have sufficient capabilities for further modification, is not investigated. Meanwhile the selective introduction of the bromine atom could create additional prerequisites for this modification, for example, makes it possible to use the cross-coupling reactions to form the C–C bond [3]. In this work the special features of δ-hydroxyalkenylphosphine oxides bromination were investigated by the example of compound I. The bromination result depends on the temperature and the initial reagents ratio. When the reaction is carried out under the mild conditions (CHCl3, –20°С), probably, the kinetically more rapid bromination of hydroxychlorophenyl substituent occurs in spite of the presence of ethylene fragment. In the Р NMR spectrum recorded immediately after reaction there is a signal at δР 94.7 ppm (intermediate DOI: 10.1134/S1070363210100348