TY - JOUR

T1 - Protonation of 3-arylpropynoic acid derivatives in superacids

AU - Walspurger, S.

AU - Vasil'ev, A. V.

AU - Sommer, J.

AU - Pale, P.

AU - Savechenkov, P. Yu

AU - Rudenko, A. P.

PY - 2005/10/1

Y1 - 2005/10/1

N2 - According to the 1H and 13C NMR data, 3-arylpropynoic acids and their esters XC6Hn-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 XC6Hn-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 XC6Hn-C+=CH-CO2R cations which are then transformed into mixtures of stereoisomeric (Z and E) fluorosulfonates or triflluoromethanesulfonates XC6Hn-CY=CH-CO2R (Y = OSO2F, OSO2CF3), the E isomer prevailing.

AB - According to the 1H and 13C NMR data, 3-arylpropynoic acids and their esters XC6Hn-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 XC6Hn-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 XC6Hn-C+=CH-CO2R cations which are then transformed into mixtures of stereoisomeric (Z and E) fluorosulfonates or triflluoromethanesulfonates XC6Hn-CY=CH-CO2R (Y = OSO2F, OSO2CF3), the E isomer prevailing.

UR - http://www.scopus.com/inward/record.url?scp=29344440303&partnerID=8YFLogxK

U2 - 10.1007/s11178-005-0371-z

DO - 10.1007/s11178-005-0371-z

M3 - Article

AN - SCOPUS:29344440303

VL - 41

SP - 1485

EP - 1492

JO - Russian Journal of Organic Chemistry

JF - Russian Journal of Organic Chemistry

SN - 1070-4280

IS - 10

ER -