32022-17-6Relevant academic research and scientific papers
Hydrolysis of Spirobicyclic Oxophosphoranes. Associative and Dissociative Reactions
McClelland, Robert A.,Patel, Geeta,Cirinna, Corrado
, p. 6432 - 6436 (2007/10/02)
The hydrolysis reactions of three aryl-substituted spirobicyclic oxyphosphoranes (Ia-c) have been studied in aqueous solution.These are characterized by an H+-catalyzed reaction extending to about pH 9.54 sharply changing there to an OH--catalyzed reaction.The acid reaction is general acid catalyzed (α=0.74) and appears to be a dissociative process directly analogous to the general acid catalyzed hydrolysis of an acetal or ortho ester.Features indicative of this type of reaction include a negative ρ value based on the variation of the aromatic substituent, a near-zero entropy of activation, and a slightly inverse solvent isotope effect.The hydroxide ion reaction appears to be an associative process proceeding through a hexacoordinated phosphoroxanide ion.Evidence for this includes a positive ρ value (+2.5) and a significantly negative entropy of activation.General base catalysis is also observed; this also appears to be an associative process on the basis of a positive ρ value.
