Mechanistic insights into the aminolysis of 3,4-epoxysulfolane презентация

Mechanistic insights into the aminolysis of 3,4-epoxysulfolane S. I. Okovytyy,1 A.V. Reshetnyak, 1 I. S. Zarovnaya,1 P.G.Dulnev,2 V. A. Palchikov 1 1Oles Honchar Dnipropetrovsk National University, Department of Organic Chemistry, Dnipropetrovsk, Ukraine 2Institute of Bioorganic chemistry and petrochemistry of NAS of Ukraine, Kyiv, Ukraine Corresponding author e-mail: sokovyty@icnanotox.org Computation details The geometries of structures of reactant complexes, intermediates, transition states and product were optimized using the M06-2X levels in conjunction with the 6-31++(d,p) basis set. Harmonic vibration frequencies were calculated at the same level of theory to characterize the stationary points (minima with all positive frequencies or transition state with only one imaginary frequency) and to calculate zero-point vibration energy. Comparison of  the ΔE‡ values for routs С1 and A1-A3 let us presume that for reactions involved NH3 molecule rearrangement could be considered  as competing mechanisms to trans opening. Transition  state TSC1  consistent with concerted but highly asynchronous process where proton from the CH2 group is transferred to the nitrogen atom while forming H-Oep bond remains within hydrogen bond lenght (around 2 Å). Values of ΔE‡ for addition of nucleophiles to allilic alcohol (2) increase  in the row OH-<NH3<H2O, herewith lengths of forming C1-X (X = N or O) bonds decrease in the same order. For addition of NH3 molecule trans attack is slightly more preferable if compare to cis- addition, while in the case of H2O and OH-  one can see the opposite picture.