Direct Metal-Free Transformation of Alkynes to Nitriles: Computational Evidence for the Precise Reaction Mechanism
Density functional theory calculations elucidated the precise reaction mechanism for the conversion of diphenylacetylenes into benzonitriles involving the cleavage of the triple C≡C bond, with <i>N</i>-iodosuccinimide (NIS) as an oxidant and trimethylsilyl azide (TMSN<sub>3</sub...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-03-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/22/6/3193 |
| _version_ | 1797540543980371968 |
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| author | Lucija Hok Robert Vianello |
| author_facet | Lucija Hok Robert Vianello |
| author_sort | Lucija Hok |
| collection | DOAJ |
| description | Density functional theory calculations elucidated the precise reaction mechanism for the conversion of diphenylacetylenes into benzonitriles involving the cleavage of the triple C≡C bond, with <i>N</i>-iodosuccinimide (NIS) as an oxidant and trimethylsilyl azide (TMSN<sub>3</sub>) as a nitrogen donor. The reaction requires six steps with the activation barrier Δ<i>G</i><sup>‡</sup> = 33.5 kcal mol<sup>−1</sup> and a highly exergonic reaction free-energy Δ<i>G</i><sub>R</sub> = −191.9 kcal mol<sup>−1</sup> in MeCN. Reaction profiles agree with several experimental observations, offering evidence for the formation of molecular I<sub>2</sub>, interpreting the necessity to increase the temperature to finalize the reaction, and revealing thermodynamic aspects allowing higher yields for alkynes with para-electron-donating groups. In addition, the proposed mechanism indicates usefulness of this concept for both internal and terminal alkynes, eliminates the option to replace NIS by its Cl- or Br-analogues, and strongly promotes NaN<sub>3</sub> as an alternative to TMSN<sub>3</sub>. Lastly, our results advise increasing the solvent polarity as another route to advance this metal-free strategy towards more efficient processes. |
| first_indexed | 2024-03-10T13:01:55Z |
| format | Article |
| id | doaj.art-2863e3b669c94cdaac4b8bc67f083c2e |
| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T13:01:55Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-2863e3b669c94cdaac4b8bc67f083c2e2023-11-21T11:24:53ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672021-03-01226319310.3390/ijms22063193Direct Metal-Free Transformation of Alkynes to Nitriles: Computational Evidence for the Precise Reaction MechanismLucija Hok0Robert Vianello1Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, CroatiaDivision of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, CroatiaDensity functional theory calculations elucidated the precise reaction mechanism for the conversion of diphenylacetylenes into benzonitriles involving the cleavage of the triple C≡C bond, with <i>N</i>-iodosuccinimide (NIS) as an oxidant and trimethylsilyl azide (TMSN<sub>3</sub>) as a nitrogen donor. The reaction requires six steps with the activation barrier Δ<i>G</i><sup>‡</sup> = 33.5 kcal mol<sup>−1</sup> and a highly exergonic reaction free-energy Δ<i>G</i><sub>R</sub> = −191.9 kcal mol<sup>−1</sup> in MeCN. Reaction profiles agree with several experimental observations, offering evidence for the formation of molecular I<sub>2</sub>, interpreting the necessity to increase the temperature to finalize the reaction, and revealing thermodynamic aspects allowing higher yields for alkynes with para-electron-donating groups. In addition, the proposed mechanism indicates usefulness of this concept for both internal and terminal alkynes, eliminates the option to replace NIS by its Cl- or Br-analogues, and strongly promotes NaN<sub>3</sub> as an alternative to TMSN<sub>3</sub>. Lastly, our results advise increasing the solvent polarity as another route to advance this metal-free strategy towards more efficient processes.https://www.mdpi.com/1422-0067/22/6/3193azidesDFT calculationscyanides<i>N</i>-iodosuccinimidetriple C≡C bond cleavage |
| spellingShingle | Lucija Hok Robert Vianello Direct Metal-Free Transformation of Alkynes to Nitriles: Computational Evidence for the Precise Reaction Mechanism International Journal of Molecular Sciences azides DFT calculations cyanides <i>N</i>-iodosuccinimide triple C≡C bond cleavage |
| title | Direct Metal-Free Transformation of Alkynes to Nitriles: Computational Evidence for the Precise Reaction Mechanism |
| title_full | Direct Metal-Free Transformation of Alkynes to Nitriles: Computational Evidence for the Precise Reaction Mechanism |
| title_fullStr | Direct Metal-Free Transformation of Alkynes to Nitriles: Computational Evidence for the Precise Reaction Mechanism |
| title_full_unstemmed | Direct Metal-Free Transformation of Alkynes to Nitriles: Computational Evidence for the Precise Reaction Mechanism |
| title_short | Direct Metal-Free Transformation of Alkynes to Nitriles: Computational Evidence for the Precise Reaction Mechanism |
| title_sort | direct metal free transformation of alkynes to nitriles computational evidence for the precise reaction mechanism |
| topic | azides DFT calculations cyanides <i>N</i>-iodosuccinimide triple C≡C bond cleavage |
| url | https://www.mdpi.com/1422-0067/22/6/3193 |
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