文摘
With the aid of density functional theory (DFT) calculations, we have investigated the mechanisms and stereoselectivities of the tandem cross Rauhut–Currier/cyclization reaction of methyl acrylate R1 with (E)-2-benzoyl-3-phenyl-acrylonitrile R2 catalyzed by a tertiary amine DABCO. The results of the DFT calculations indicate that the favorable mechanism (mechanism A) includes three steps: the first step is the nucleophilic attack of DABCO on R1 to form intermediates Int1 and Int1-1, the second step is the reaction of Int1 and Int1-1 with R2 to generate intermediate Int2(SS,RR,SR&RS), and the last step is an intramolecular SN2 process to give the final product P(SS,RR,SR&RS) and release catalyst DABCO. The SN2 substitution is computed to be the rate-determining step, whereas the second step is the stereoselectivity-determining step. The present study may be helpful for understanding the reaction mechanism of similar tandem reactions.