Mechanistic studies of the oxidation of substituted phenethyl alcohols by N‐metallo‐N‐haloarylsulphonamides: kinetic isotope studies

Abstract

The oxidation of para-substituted phenethyl alcohols (PEA, 2) by N-metallo-N-haloarylsulphonamides (1) in the presence of dilute HCl to the corresponding phenacetaldehydes (4) is first order with respect to oxidant (1) and [H ] and a fractional order each in [PEA] and [Cl À ]. Addition of the reaction product (3), ionic strength variations and variation of dielectric constant of the medium had no effect on the rate. The oxidation of PhCH 2 CD 2 OH (2) exhibited a substantial primary kinetic isotope effect (k H /k D = 5.83). The rates correlate satisfactorily with the Hammett free energy relationship. The activation parameters DH ≠ , DS ≠ , DG ≠ and logA were calculated for the reaction. The proposed mechanism is consistent with the observed results. RESULTS AND DISCUSSIONOxidation of 2 by 1 revealed that 1 mol of 1 was JOURNAL OF PHYSICAL ORGANIC CHEMISTRY

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