Interestingly, in the TS11-3b at the C 1 -H 1 bcp  2 b > 0, which is a characteristic of closed-shell interaction, while for the remaining TS11-3x,  2 b < 0. Thus, in TS11-3b the breaking of the C 1 -H 1 bond and the formation of the H 1 -OMeO bond were more advanced than in the other TS11-3x.