作者:S. Walspurger、A. V. Vasil'ev、J. Sommer、P. Pale、P. Yu. Savechenkov、A. P. Rudenko
DOI:10.1007/s11178-005-0371-z
日期:2005.10
According to the 1H and 13C NMR data, 3-arylpropynoic acids and their esters XC6H n -C≡C-CO2R (R = H, Me, Et) having electron-withdrawing substituents in the benzene ring (X = NO2, CN, COMe, CO2Me) exist in HSO3F at −80 to 0°C as XC6H n -C≡C-C+(OH)OR ions. Derivatives with other substituents (X = H, F, Me, MeO) in HSO3F or CF3SO3H above −40°C undergo protonation at the acetylenic carbon atom neighboring to the acid group to give unstable vinyl-type XC6H n -C+=CH-CO2R cations which are then transformed into mixtures of stereoisomeric (Z and E) fluorosulfonates or triflluoromethanesulfonates XC6H n -CY=CH-CO2R (Y = OSO2F, OSO2CF3), the E isomer prevailing.
根据1H和13C NMR数据,在苯环上带有吸电子取代基(X = NO2、CN、COMe、CO2Me)的3-芳基丙炔酸及其酯XC6H n -C≡C-CO2R(R = H、Me、Et)在HSO3F中以XC6H n -C≡C-C+(OH)OR离子的形式存在于-80至0°C的温度范围内。在HSO3