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Theoretical investigation on the rhodium-catalyzed coupling reaction of ketoxime with 1,3-enynes: [4 + 1] vs. [4 + 2] annulation
  • Xiao Yun,
  • Zhangyu Yu,
  • Tao Liu
Xiao Yun
Qufu Normal University
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Zhangyu Yu
Jining University
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Tao Liu
Jining University
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Peer review status:UNDER REVIEW

18 Jun 2020Submitted to International Journal of Quantum Chemistry
19 Jun 2020Assigned to Editor
19 Jun 2020Submission Checks Completed
10 Jul 2020Reviewer(s) Assigned

Abstract

The mechanisms of rhodium-catalyzed coupling reaction of ketoxime and 1,3-enynes were investigated by employing the density functional theory (DFT) calculations. Different 1,3-enynes would lead to different annulation products. Reaction A undergoes five sequential steps (C-H activation, 1,3-enyne migratory insertion, 1,4-Rh migration, cyclization, and deprotonation) to lead to [4 + 1] annulation product. Whereas, due to the electronic effect, the process generating [4 + 2] product in reaction A is restricted. In contrast, the electron-withdrawing group of N(Me)2 group in 1,3-enyne would bring about the [4 + 2] annulation product in reaction B. Our calculated results indicate that no [4 + 1] annulation product could be obtained in reaction C, in agreement with the experimental observation that the cis-allyl hydrogen in 1,3-enyne is crucial for the [4 + 1] annulation reaction.