Chiral 2-Aminobenzimidazole as Bifunctional Catalyst in the Asymmetric Electrophilic Amination of Unprotected 3-Substituted Oxindoles
The use of readily available chiral trans-cyclohexanediamine-benzimidazole derivatives as bifunctional organocatalysts in the asymmetric electrophilic amination of unprotected 3-substituted oxindoles is presented. Different organocatalysts were evaluated; the most successful one contained a dimethyl...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2018-06-01
|
| Series: | Molecules |
| Subjects: | |
| Online Access: | http://www.mdpi.com/1420-3049/23/6/1374 |
| _version_ | 1828860574278090752 |
|---|---|
| author | Llorenç Benavent Alejandro Baeza Megan Freckleton |
| author_facet | Llorenç Benavent Alejandro Baeza Megan Freckleton |
| author_sort | Llorenç Benavent |
| collection | DOAJ |
| description | The use of readily available chiral trans-cyclohexanediamine-benzimidazole derivatives as bifunctional organocatalysts in the asymmetric electrophilic amination of unprotected 3-substituted oxindoles is presented. Different organocatalysts were evaluated; the most successful one contained a dimethylamino moiety (5). With this catalyst under optimized conditions, different oxindoles containing a wide variety of substituents at the 3-position were aminated in good yields and with good to excellent enantioselectivities using di-tert-butylazodicarboxylate as the aminating agent. The procedure proved to be also efficient for the amination of 3-substituted benzofuranones, although with moderate results. A bifunctional role of the catalyst, acting as Brønsted base and hydrogen bond donor, is proposed according to the experimental results observed. |
| first_indexed | 2024-12-13T02:42:49Z |
| format | Article |
| id | doaj.art-3d1575b126c440f1814233e2df0bcfbd |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-12-13T02:42:49Z |
| publishDate | 2018-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-3d1575b126c440f1814233e2df0bcfbd2022-12-22T00:02:15ZengMDPI AGMolecules1420-30492018-06-01236137410.3390/molecules23061374molecules23061374Chiral 2-Aminobenzimidazole as Bifunctional Catalyst in the Asymmetric Electrophilic Amination of Unprotected 3-Substituted OxindolesLlorenç Benavent0Alejandro Baeza1Megan Freckleton2Departamento de Química Orgánica and Instituto de Síntesis Orgánica (ISO), Facultad de Ciencias, Universidad de Alicante, Apdo. 99, E-03080 Alicante, SpainDepartamento de Química Orgánica and Instituto de Síntesis Orgánica (ISO), Facultad de Ciencias, Universidad de Alicante, Apdo. 99, E-03080 Alicante, SpainDepartamento de Química Orgánica and Instituto de Síntesis Orgánica (ISO), Facultad de Ciencias, Universidad de Alicante, Apdo. 99, E-03080 Alicante, SpainThe use of readily available chiral trans-cyclohexanediamine-benzimidazole derivatives as bifunctional organocatalysts in the asymmetric electrophilic amination of unprotected 3-substituted oxindoles is presented. Different organocatalysts were evaluated; the most successful one contained a dimethylamino moiety (5). With this catalyst under optimized conditions, different oxindoles containing a wide variety of substituents at the 3-position were aminated in good yields and with good to excellent enantioselectivities using di-tert-butylazodicarboxylate as the aminating agent. The procedure proved to be also efficient for the amination of 3-substituted benzofuranones, although with moderate results. A bifunctional role of the catalyst, acting as Brønsted base and hydrogen bond donor, is proposed according to the experimental results observed.http://www.mdpi.com/1420-3049/23/6/1374organocatalysiselectrophilic aminationbenzimidazolesasymmetric catalysisoxindoles |
| spellingShingle | Llorenç Benavent Alejandro Baeza Megan Freckleton Chiral 2-Aminobenzimidazole as Bifunctional Catalyst in the Asymmetric Electrophilic Amination of Unprotected 3-Substituted Oxindoles Molecules organocatalysis electrophilic amination benzimidazoles asymmetric catalysis oxindoles |
| title | Chiral 2-Aminobenzimidazole as Bifunctional Catalyst in the Asymmetric Electrophilic Amination of Unprotected 3-Substituted Oxindoles |
| title_full | Chiral 2-Aminobenzimidazole as Bifunctional Catalyst in the Asymmetric Electrophilic Amination of Unprotected 3-Substituted Oxindoles |
| title_fullStr | Chiral 2-Aminobenzimidazole as Bifunctional Catalyst in the Asymmetric Electrophilic Amination of Unprotected 3-Substituted Oxindoles |
| title_full_unstemmed | Chiral 2-Aminobenzimidazole as Bifunctional Catalyst in the Asymmetric Electrophilic Amination of Unprotected 3-Substituted Oxindoles |
| title_short | Chiral 2-Aminobenzimidazole as Bifunctional Catalyst in the Asymmetric Electrophilic Amination of Unprotected 3-Substituted Oxindoles |
| title_sort | chiral 2 aminobenzimidazole as bifunctional catalyst in the asymmetric electrophilic amination of unprotected 3 substituted oxindoles |
| topic | organocatalysis electrophilic amination benzimidazoles asymmetric catalysis oxindoles |
| url | http://www.mdpi.com/1420-3049/23/6/1374 |
| work_keys_str_mv | AT llorencbenavent chiral2aminobenzimidazoleasbifunctionalcatalystintheasymmetricelectrophilicaminationofunprotected3substitutedoxindoles AT alejandrobaeza chiral2aminobenzimidazoleasbifunctionalcatalystintheasymmetricelectrophilicaminationofunprotected3substitutedoxindoles AT meganfreckleton chiral2aminobenzimidazoleasbifunctionalcatalystintheasymmetricelectrophilicaminationofunprotected3substitutedoxindoles |