Effect of high pressure on Michael and Henry reactions between ketones and nitroalkanes

Abstract

The kinetic pressure effect on some specific Michael and Henry reactions is investigated. The observed activation volumes of the Michael reaction between nitromethane and methyl vinyl ketone are largely dependent on the magnitude of the electrostriction effect, which is highest in the lanthanide-catalyzed reaction, still important in the aqueous reaction and lowest in the base-catalyzed version. In the latter case, the reverse reaction is insensitive to pressure. These results apply also to the Henry addition of nitroalkanes to ketones. The positive pressure effect can be used for the chemoselective synthesis of nitroalcohols from ketones.