DFT Studies on theAminolysis of Methyl (Thio)Chloro Formates in Acetonitrile

초록

Lots of experimental and theoretical studies have been performed on the aminolysis of carbonyl and thiocarbonyl transfer reactions. The reaction mechanism is still not clear as there are three possible pathways ? (1) concerted bimolecular single-step, (2) stepwise addition-elimination, and (3) eliminationaddition type mechanisms. Unfortunately, the reaction mechanism involving a planner back-side nucleophilic attack to the leaving group is not possible due to a high energy barrier. To understand the reaction mechanism, we performed DFT calculations at the B3LYP/6-311+G(d,p) level of theory in acetonitrile solvent as the zwitterionic species are formed during the reaction. The calculations show that the concerted nucleophilic attack towards the reaction centre favoured over the stepwise one. The structures and energetics will be discussed in detail.