Figure 5.

Geometries and relatives stabilities for the reactants, rate-limiting transition states, and final products for the four proposed mechanisms for acetal cleavage calculated with PCM(H₂O)/M06-2X/6-31+G(d,p): water-assisted hydrolysis (pathway A), neutral amine-assisted hydrolysis (pathway B), charged ammonium-assisted hydrolysis (pathway C), and water-assisted aminolysis (pathway D). Relative free energies (ΔG and ΔG^⧧) are given in kcal·mol^–1 and interatomic distances in angstroms. Hydrogen bond interactions are shown as dotted red lines. Breaking/forming bonds on the transition states are shown as dotted green lines. The whole computed reaction pathways C and D are available in the Supporting Information (Figure S30).