Reduction of acetophenone using supercritical 2-propanol: the substituent effect and the deuterium kinetic isotope effect

Abstract

The reductions of several substituted acetophenones using supercritical 2-propanol were carried out to estimate the Hammett's reaction constant ( ρ=0.33). Also, the reduction of acetophenone using supercritical deuteriated 2-propanol was carried out to determine the rate-determining step. The kinetic isotope effects were observed in the reduction using 2-deuterio-2-propanol ( k H/ k D=1.6) and O-deuterio-2-propanol ( k H/ k D=2.0). These findings suggest that the reaction proceeds via a cyclic transition state between acetophenone and 2-propanol similar to that of the Meerwein–Ponndorf–Verley reduction.