Nucleophilic substitution reactions of indan-2-yl arenesuifonates with anilines in methanol

Abstract

The nucleophilic substitution reactions of (Y)-indan-2-yl (Z)-arenesulfonates with (X)-anilines in methanol at 55.0 °C are reported. Sign reversals in all three second-order cross-interaction constants, ρ_xy, ρ_yz and ρ_xz, are observed at non-interaction points _z=–0.11 (ρ_xy= 0), _x=–0.02 (ρ_yz= 0) and _Y= 0.43 (ρ_xz= 0) respectively, which have been ascribed to an unusually large third-order cross-interaction constant, ρ_xyz=–0.53, for the reaction series. An S_N2 transition state with a tilted, parallel stacked and displaced structure of the three benzene rings in the nucleophile (X), substrate (Y) and leaving group (Z) is proposed to rationalize the strong three-body coupling manifested by the large ρ_xyz value.