Aldol condensation of trifluoroacetophenone and acetone: Testing a prediction

Rate and equilibrium constants have been determined for both stages of the aldol condensation of acetone with trifluoroacetophenone. The extensive hydration of trifluoroacetophenone and the acid dissociation of the hydrate complicated the kinetic analysis. Dehydration of the intermediate ketol leads to two enones which equilibrate in base more rapidly than they undergo hydration to the ketol. This is consistent with interconversion via the enolate of the ketol, which loses OH- faster than it undergoes C-protonation. The rate constant determined for the aldol addition step is in satisfactory agreement with the value predicted from a Marcus correlation.