Kinetics and mechanism of aminolysis of propargyl and 1‐methyl‐propargyl arenesulphonates

Kinetic studies were carried out on the aminolysis of propargly and 1‐methylpropargyl arenesulphonates in acetonitrile at 45·0°C. The cross‐interaction constants, ρ xz and β xz , are similar to, but smaller than, those for the S N 2 processes at other primary and secondary carbon centers. Compared with the allyl series, the smaller magnitude of ρ xz and β xz reflects a looser transition state, which in turn leads to a lower rate despite the greater Taft's σ* value and the lower intrinsic (Δ E   0 ≠ ) and thermodynamic barriers (Δ E 0 ).