Revisiting the Mechanism of Neutral Hydrolysis of Esters: Water Autoionization Mechanisms with Acid or Base Initiation Pathways

摘要: The mechanism of neutral hydrolysis ester has long been explored by theoretical studies. However, reliable calculations show that the usual bifunctional catalysis reported different authors cannot explain experimental kinetics. An important advance was recently Gunaydin and Houk, suggesting ions are involved in process initiates water autoionization followed protonation (W(AI)A mechanism). this does not activated esters. In work, we have used ab initio calculations, continuum solvation models, intrinsic reaction coordinate method to support W(AI)A for normal ester. case esters, can also be viewed as with formation hydroxide ion aided a second molecule acting general base (W(AI)B This is proposed Jencks Carriuolo 50 years ago. Our analysis point out exploring mechanisms, searching saddle points, may work problems like present one, since there no points on pathway. Rather, pair from species an asymptotic barrier. approach paper allows calculation free energy profile enable us kinetics (methyl acetate) trifluoroacetate) addition, study suggests should always considered reactions aqueous solution.