STEREOSELECTIVITY IN THE REACTIONS OF PHENOLYSIS OF CYCLIC PHOSPHASENES UNDER CONDITIONS OF TRANSPHASE CATALYSIS

Abstract

The reactions of phenolysis of cyclophos­phazenes, leading to the formation of mono­aryl oxide derivatives with an excess of the substrate, were studied. The interest in this reaction is dictated by the practical value of the reaction products, which are easily formed under the conditions of transphase catalysis, and also by the fact that the studied regula­rities of phenolysis can extend to a significant spectrum of transphase nucleophilic substitution reactions. The general regularities of the transphase reaction of phosphazenes phenolysis were established by the example of the interaction of 4-nitrophenol with a phosphornitrile chloride trimer in a two-phase system. It was shown that the topology of the transphase chemical interaction is influenced by the same factors as the limiting stage, and therefore, by varying the ratio of lipophilicity and nucleophilicity of the transphase reagent, one can purposefully change the place of its interaction with the substrate. It was shown that the phenolysis of cyclotriphosphazenes occurs in the bulk of the organic phase or, alternatively, in the organic sublayer adjacent to the phase separation boundary. The presen­ted data suggested that the transphase reaction can be described in terms of a single mecha­nism, in contrast to the generally accepted division into extraction and phase transfer. Thus, the topology of the transphase chemical interaction is influenced by the same factors as the limiting stage, and therefore, by vary­ing the ratio of lipophilicity and nucleophili­city of transphase reagents, one can purpose­fully change the zone of their interaction with the substrate. In this case, the rate of the ho­mogeneous response and the hyd­rophilicity of the ionic agent must be ta­ken into account. The features of the transphase reaction des­cribed here can be extended to other catalysts, such as betaines, the analogs of which have been used in various reactions of a similar type.