New insights into the Lewis acidity of guanidinium species: Lewis acid interaction provides reactivity
A unique reactivity pattern in which the catalyst and the reactant motifs are joined together in a substrate is investigated using density functional theory calculations. The versatile triaza CN3 functionality in bicyclic guanidines is combined with a diversity of functional groups about the molecul...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Académie des sciences
2020-06-01
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| Series: | Comptes Rendus. Chimie |
| Subjects: | |
| Online Access: | https://comptes-rendus.academie-sciences.fr/chimie/articles/10.5802/crchim.16/ |
| _version_ | 1827785196701745152 |
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| author | Ashraf, Muhammad Ageel Li, Cheng Norouzi, Fataneh Zhang, Dangquan |
| author_facet | Ashraf, Muhammad Ageel Li, Cheng Norouzi, Fataneh Zhang, Dangquan |
| author_sort | Ashraf, Muhammad Ageel |
| collection | DOAJ |
| description | A unique reactivity pattern in which the catalyst and the reactant motifs are joined together in a substrate is investigated using density functional theory calculations. The versatile triaza CN3 functionality in bicyclic guanidines is combined with a diversity of functional groups about the molecular scaffold which, upon addition of N-nucleophiles, transfers the substrate to its hitherto unreported tricyclic analogues. Unprecedentedly, the guanidine/guanidinium dyad advances the reaction by displaying all possible chemical functionalities, including Brønsted acid–base and Lewis acid–base activation modes. This study presents the first example of a guanidine-catalyzed thioamidation reaction. Furthermore, it evidences the first participation of guanidinium’s Lewis acid activation in a cyclization reaction. In addition to the several mono- and bifunctional activation modes, two rare examples of Lewis acid interaction were observed, which provides important mechanistic points. The first one in the thioamidation step suggests the preference for stepwise elimination of MeSH over the alternative concerted mechanisms. However, the second one in the N-Michael addition step provides a new insight into the Lewis acidity activation mode of guanidinium species. The interaction first traps the side branch of the substrate containing the nucleophilic motif and then, by positioning the anionic nucleophile and the Michael acceptor site in close proximity, navigates the regioselective N-Michael addition. |
| first_indexed | 2024-03-11T16:14:42Z |
| format | Article |
| id | doaj.art-e02525ccbcc743508ec4c968b55de79a |
| institution | Directory Open Access Journal |
| issn | 1878-1543 |
| language | English |
| last_indexed | 2024-03-11T16:14:42Z |
| publishDate | 2020-06-01 |
| publisher | Académie des sciences |
| record_format | Article |
| series | Comptes Rendus. Chimie |
| spelling | doaj.art-e02525ccbcc743508ec4c968b55de79a2023-10-24T14:22:41ZengAcadémie des sciencesComptes Rendus. Chimie1878-15432020-06-0123218519910.5802/crchim.1610.5802/crchim.16New insights into the Lewis acidity of guanidinium species: Lewis acid interaction provides reactivityAshraf, Muhammad Ageel0Li, Cheng1Norouzi, Fataneh2Zhang, Dangquan3School of Forestry, Henan Agricultural University, Zhengzhou 450002, China; Department of Geology, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, MalaysiaSchool of Forestry, Henan Agricultural University, Zhengzhou 450002, ChinaDepartment of Chemistry, Shahid Beheshti University, General Campus, 1983963113, Tehran, IranSchool of Forestry, Henan Agricultural University, Zhengzhou 450002, ChinaA unique reactivity pattern in which the catalyst and the reactant motifs are joined together in a substrate is investigated using density functional theory calculations. The versatile triaza CN3 functionality in bicyclic guanidines is combined with a diversity of functional groups about the molecular scaffold which, upon addition of N-nucleophiles, transfers the substrate to its hitherto unreported tricyclic analogues. Unprecedentedly, the guanidine/guanidinium dyad advances the reaction by displaying all possible chemical functionalities, including Brønsted acid–base and Lewis acid–base activation modes. This study presents the first example of a guanidine-catalyzed thioamidation reaction. Furthermore, it evidences the first participation of guanidinium’s Lewis acid activation in a cyclization reaction. In addition to the several mono- and bifunctional activation modes, two rare examples of Lewis acid interaction were observed, which provides important mechanistic points. The first one in the thioamidation step suggests the preference for stepwise elimination of MeSH over the alternative concerted mechanisms. However, the second one in the N-Michael addition step provides a new insight into the Lewis acidity activation mode of guanidinium species. The interaction first traps the side branch of the substrate containing the nucleophilic motif and then, by positioning the anionic nucleophile and the Michael acceptor site in close proximity, navigates the regioselective N-Michael addition.https://comptes-rendus.academie-sciences.fr/chimie/articles/10.5802/crchim.16/Cyclic guanidineGuanidinium catalystGuanidine catalystLewis acid activationReagent/catalyst activity |
| spellingShingle | Ashraf, Muhammad Ageel Li, Cheng Norouzi, Fataneh Zhang, Dangquan New insights into the Lewis acidity of guanidinium species: Lewis acid interaction provides reactivity Comptes Rendus. Chimie Cyclic guanidine Guanidinium catalyst Guanidine catalyst Lewis acid activation Reagent/catalyst activity |
| title | New insights into the Lewis acidity of guanidinium species: Lewis acid interaction provides reactivity |
| title_full | New insights into the Lewis acidity of guanidinium species: Lewis acid interaction provides reactivity |
| title_fullStr | New insights into the Lewis acidity of guanidinium species: Lewis acid interaction provides reactivity |
| title_full_unstemmed | New insights into the Lewis acidity of guanidinium species: Lewis acid interaction provides reactivity |
| title_short | New insights into the Lewis acidity of guanidinium species: Lewis acid interaction provides reactivity |
| title_sort | new insights into the lewis acidity of guanidinium species lewis acid interaction provides reactivity |
| topic | Cyclic guanidine Guanidinium catalyst Guanidine catalyst Lewis acid activation Reagent/catalyst activity |
| url | https://comptes-rendus.academie-sciences.fr/chimie/articles/10.5802/crchim.16/ |
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