85152-57-4Relevant articles and documents
THE PROTON ACTIVATING FACTOR AND ITS APPLICATION TO ACID AND BASE CATALYSIS OF ALDEHYDE HYDRATION
Stewart, Ross
, p. 907 - 910 (2007/10/02)
The data of McClelland and Coe for the general acid and general base catalyzed hydration of a series of substituted benzaldehydes has been analyzed in terms of the proton activating factor, paf, and concepts related thereto.Although the latter were derived for use with prototropic systems, the present work shows that they have application to nucleophilic addition as well.Three conclusions emerge from the analysis.1.Alternative means of calculating paf from buffer catalytic data that were previously derived on theoretical grounds can be used in practice to give essentially the same results.2.The mechanism of the general acid catalyzed pathway for aldehyde hydration is that favoured by McLelland and Coe and by Jencks, to wit the class (e) mechanism, rather than the class (n) mechanism.3.Electron-withdrawing groups in the benzaldehyde ring cause the disparity between the contributions of alternative, kinetically equivalent, pathways for the uncatalyzed reaction to become greater.