Case Study Isomerization of Propylene Oxide

Synopsis of Dubnikova and Lifshitz (2000) Isomerization of Propylene Oxide. Quantum Chemical Calculations and Kinetic Modeling . 

Because of the complexity of the molecular hypersurface, the authors chose the B3LYP level in combination witli the cc-pVDZ basis set for their search for TS structures. Based on judgment and intuition, tliey chose initial geometries for TS structures and optimized them subject to the constraint of there being a single imaginary frequency in the product stationary 

Nevertheless, the agreement that is obtained - which is probably the best one should expect given the small size of the basis set used in the CCSD(T) calculations and the possible problems associated with biradical character in the methyl vinyl ether pathway - suggests that the theoretically predicted TS structures are accurate representations of the actual transition states. This establishes the concerted nature of three of the rearrangements and the stepwise nature of the fourth. 

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