Theoretical study on the reaction mechanisms and stereoselectivities of DABCO-catalyzed Rauhut-Currier/cyclization reaction of methyl acrylate with 2-benzoyl-3-phenyl-acrylonitrile

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• 作者：Yan Li and Shiwen Du
• 刊名：International Journal of Quantum Chemistry
• 出版年：2017
• 出版时间：February 15, 2017
• 年：2017
• 卷：117
• 期：4
• 全文大小：1079K
• ISSN：1097-461X

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 S_N2 process to give the final product P(SS,RR,SR&RS) and release catalyst DABCO. The S_N2 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.