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Mechanistic insights into the origin of substituent-directed product Z-E selectivity for gold-catalyzed [4+1]-annulations of 1,4-diyn-3-ols with isoxazoles: A DFT study | |
Wang, Kaifeng; Liu, Yuxia; Wu, Qiao; Liu, Lingjun; Li, Yulin![]() | |
2020 | |
发表期刊 | MOLECULAR CATALYSIS
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卷号 | 480 |
摘要 | Density functional theory (DFT) calculations were used to explore the Au(I)-catalyzed selective [4 + 1] annulations of cyclopropyl- and H-substituted 1,4-diyn-3-ols with isoxazole. The results indicated that after the N-nucleophilic attack of isoxazole, instead of obtaining the alpha-hydroxy gold carbene intermediate proposed experimentally, a concerted three-step forward product by isoxazole O-N cleavage, 1,2-phenylalkyne shift and the hydroxyl H shift was identified as the key intermediate, for the reaction proceeding either via an Au-assisted C=C double-bond rotation to produce the Z-isomeric enone or via two different Au-assisted C=C rotations to furnish the E-configured enone depending on the substituents used. Further theoretical investigations indicated that the chemoselective step is the nucleophilic cyclization but not the C=C double-bond rotation. The chemoselective preference for the Z-configured product using the cyclopropyl substitutent was attributed to two factors: i) the additional O H-N hydrogen bonding interaction stabilizes the rate-determining cyclization TS leading to the Z-product, and ii) further Z-E product-isomerization is blocked due to significant structural deformation being involved. In contrast, using the H substituent results in a reversed chemoselectivity with exclusive formation of the E-configured enone, which is closely related to the smaller entropy effects involved. |
关键词 | Au(I)-catalysis [4+1] annulation 1,4-diyn-3-ols Selectivity DFT |
文献类型 | 期刊论文 |
条目标识符 | http://210.75.249.4/handle/363003/59670 |
专题 | 中国科学院西北高原生物研究所 |
推荐引用方式 GB/T 7714 | Wang, Kaifeng,Liu, Yuxia,Wu, Qiao,et al. Mechanistic insights into the origin of substituent-directed product Z-E selectivity for gold-catalyzed [4+1]-annulations of 1,4-diyn-3-ols with isoxazoles: A DFT study[J]. MOLECULAR CATALYSIS,2020,480. |
APA | Wang, Kaifeng.,Liu, Yuxia.,Wu, Qiao.,Liu, Lingjun.,Li, Yulin.,...&Bi, Siwei.(2020).Mechanistic insights into the origin of substituent-directed product Z-E selectivity for gold-catalyzed [4+1]-annulations of 1,4-diyn-3-ols with isoxazoles: A DFT study.MOLECULAR CATALYSIS,480. |
MLA | Wang, Kaifeng,et al."Mechanistic insights into the origin of substituent-directed product Z-E selectivity for gold-catalyzed [4+1]-annulations of 1,4-diyn-3-ols with isoxazoles: A DFT study".MOLECULAR CATALYSIS 480(2020). |
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