The mechanism, catalytic effect and solvent effect of the hetero-Diels-Alder reactions between 3-pyddinedithioesters and 1-phenylsulfanylbutadiene have been studied theoretically using density functional theory （DFT...The mechanism, catalytic effect and solvent effect of the hetero-Diels-Alder reactions between 3-pyddinedithioesters and 1-phenylsulfanylbutadiene have been studied theoretically using density functional theory （DFT） at the B3LYP/6-31G（d） level. The results show that all of these reactions proceed in a concerted but asynchronous way. In some reactions the formation of C-S bond is prior to that of C-C bond and the opposite results are found in other reactions. The BF3 catalyst may lower the activation barriers by changing the energies of LUMO for 3-pyridinedithioester. THF solvent has trivial influence on the potential energy surface of these reactions. With the BF3-catalyzed reactions, regioselectivity and stereoselectivity observed experimentally were predicted correctly by calculations and these results originate probably from C-H…F interaction in two transition states.展开更多
文摘The mechanism, catalytic effect and solvent effect of the hetero-Diels-Alder reactions between 3-pyddinedithioesters and 1-phenylsulfanylbutadiene have been studied theoretically using density functional theory （DFT） at the B3LYP/6-31G（d） level. The results show that all of these reactions proceed in a concerted but asynchronous way. In some reactions the formation of C-S bond is prior to that of C-C bond and the opposite results are found in other reactions. The BF3 catalyst may lower the activation barriers by changing the energies of LUMO for 3-pyridinedithioester. THF solvent has trivial influence on the potential energy surface of these reactions. With the BF3-catalyzed reactions, regioselectivity and stereoselectivity observed experimentally were predicted correctly by calculations and these results originate probably from C-H…F interaction in two transition states.
