Substituent Effects. XVI. Acetolysis of 2-Phenylethyl Tosylates

Article abstract of DOI:10.1246/bcsj.60.1091

The acetolysis rates of 2-arylethyl tosylates were determined for a series of aryl substituents.The non-linear substituent effect was reasonably accounted for on the basis of two linear LArSR relationships; one for the aryl-assisted (Fk_Δ) and one for the unassisted (K_s) process, respectively.A precise dissection of the apparent substituent effect into individual effects for both processes was achieved in this manner.The substituent effect on the k_s process can be described as a linear function of ?⁰ with a small ρ_s of -0.19, and that on the Fk_Δ process in terms of the LArSR Eq., with a ρ_Δ=-3.87 and an r_Δ=0.631.The use of ?⁺ for the Fk_Δ process failed to give any reasonable dissection.The r value for this Fk_Δ process is essentially identical to that for the neophyl solvolysis.The unique r value oh 0.6 is concluded to be characteristic of β-aryl-assisted ionization processes in general.