174191-08-3Relevant academic research and scientific papers
?-Complex Formation and Side-chain Proton Transfer from 2,4,6-tris(Trifluoromethylsulfonyl) Toluene in Methanol
Terrier, F.,Chatrousse, A.-P.,Kizilian, E.,Ignatev, N. V.,Yagupolskii, L. M.
, p. 627 - 631 (2007/10/02)
Kinetic studies of the interaction of 2,4,6-tris(trifluoromethylsulfonyl) toluene (TTST) with methoxide ion in methanol have been made.Two competitive processes have been identified: ?-adduct formation from methoxide addition at the unsubstituted 3-position occurs first but it is followed by the transfer of a side chain proton to give a carbanion (2b) of much higher thermodynamic stability (pKa = 9.46) than the ?-adduct (1b : pKa = 11.42).The high stability of 2b is shown to derive from an extensive delocalization of its negative charge through the three SO2CF3 groups.Rates of deprotonation of TTST by a variety of phenoxide and carboxylate ions (B1-) and of protonation of the resulting carbanion 2b by the conjugated acids BH have been also measured.No difference in the efficiency of the two classes of catalysts to assist the proton transfer has been found.The Broensted βB coefficient for the deprotonation step is equal to 0.46, consistent with findings for many other benzylic-type carbon acids.In agreement with the idea that extensive molecular, electronic and solvational reorganization is required to produce an highly delocalized carbanion, TTST is found to be a carbon acid of low intrinsic reactivity.
