Figure 6. Intrinsic reaction coordinate (IRC) curve of TS2 and energy level diagram of elementary reaction 2.
Elementary reaction 3.
The intramolecular reaction of intermediate med1, which was formed by elementary reaction 2, can occur through the following two pathways.
Path 1: The electron-rich O atom of the nitroso group attacks the C atom on the Carbonyl directly, and intermediate med1 is cyclized through the five-membered transition state, TS3’, to form intermediate med1-1. The electron-rich O(14) atom of med1-1 is then protonated in solution to form product 3a , as shown in Figure 7.