β-DEUTERIUM KINETIC ISOTOPE EFFECTS IN THE SOLVOLYSIS OF 2-ARYL-1,1,1-TRIFLUORO-2-PROPYL TOSYLATES AND OF 2-ARYL-2-PROPYL p-NITROBENZOATES. EVIDENCE FOR A VARIATION OF THE CONTRIBUTION OF α-METHYL SUBSTITUENT IN STABILIZING CATIONIC REACTION CENTERS WITH DIFFERENT ELECTRON DEMAND

Article abstract of DOI:10.1016/S0040-4039(00)84865-0

A very high β-deuterium kinetic isotope effect, k(CH3)/k(CD3)=2.13 at 60 deg C, was found for the solvolysis of 2-(3'-chlorophenyl)-1,1,1-trifluoro-2-propyl tosylate (2c) and the α-CD3 analogue (4c), and the effect decreased with increasing electron attracting of the substituent on the aromatic ring which showed the variation of the contribution of α-methyl group to the stabilization of the cationic reaction center in the transition state.