Secondary deuterium isotope effects for hydrolysis of acetals and orthoformates

Abstract

Kinetic secondary deuterium isotope effects for the hydrolysis of ethyl orthoformate and propionaldehyde diethylacetal reveal that the transition state resembles the substrate in the former case and the carbonium-ion intermediate in the latter; for substituted benzaldehyde diethylacetal hydrolysis, the transition states increasingly resemble the carbonium-ion intermediates as the electron withdrawing power of the polar substitutent increases.