3.3 Reaction C
As reported in this experiment, under the catalysis of cat and AgOAc, P2 is the product. As presented in Figure 6, the ring-opening caused by the protonation of HOAc (TS1-P2C ) is much favorable than theβ -carbon elimination pathway (TS1-P1C ), suggesting P2 is the product, in agreement with the experimental observation. The reversion on the selectivity, caused by different additives, could be attributed to the electronic effect. As the NBO charges shown in Figures 6 and 7, compared with HCO3-, the stronger acidity of HOAc could give the proton more easily and facilitate the ring-opening process.
FIGURE 6 The optimized structures of transition states ofTS1-P1C andTS1-P2C . The NBO charges are given in