Selective ring expansion and C−H functionalization of azulenes
Abstract We report a transition metal-catalyzed ring expansion of azulene that can be contrasted with C–H functionalization. This study represents the first example of the successful ring expansion of azulene using Cu(hfacac)2 (hfacac: hexafluoroacetylacetonate) with a diazo reagent. This result is...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2023-12-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-023-43200-7 |
| _version_ | 1797414758374178816 |
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| author | Sangjune Park Cheol-Eui Kim Jinhoon Jeong Ho Ryu Chanyoung Maeng Dongwook Kim Mu-Hyun Baik Phil Ho Lee |
| author_facet | Sangjune Park Cheol-Eui Kim Jinhoon Jeong Ho Ryu Chanyoung Maeng Dongwook Kim Mu-Hyun Baik Phil Ho Lee |
| author_sort | Sangjune Park |
| collection | DOAJ |
| description | Abstract We report a transition metal-catalyzed ring expansion of azulene that can be contrasted with C–H functionalization. This study represents the first example of the successful ring expansion of azulene using Cu(hfacac)2 (hfacac: hexafluoroacetylacetonate) with a diazo reagent. This result is notable for extending the Buchner reaction, previously limited to benzenoid aromatics, to nonbenzenoid compounds. The chemoselectivity of the reaction can be directed towards C–H functionalization by substituting the Cu catalyst with AgOTf. This approach does not require the addition of phosphine, NHC, or related ligands, and prefunctionalization of azulenes is unnecessary. Furthermore, the method exhibits excellent functional group tolerance, allowing for the synthesis of a wide range of 6,7-bicyclic compounds and C–H functionalized azulenes. We also present a theoretical study that explains the experimental observations, explaining why copper afford the ring expansion product while silver forms the C–H alkylation product. |
| first_indexed | 2024-03-09T05:38:26Z |
| format | Article |
| id | doaj.art-e24ac934301f40bf9279bd99537408b5 |
| institution | Directory Open Access Journal |
| issn | 2041-1723 |
| language | English |
| last_indexed | 2024-03-09T05:38:26Z |
| publishDate | 2023-12-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Nature Communications |
| spelling | doaj.art-e24ac934301f40bf9279bd99537408b52023-12-03T12:27:29ZengNature PortfolioNature Communications2041-17232023-12-011411910.1038/s41467-023-43200-7Selective ring expansion and C−H functionalization of azulenesSangjune Park0Cheol-Eui Kim1Jinhoon Jeong2Ho Ryu3Chanyoung Maeng4Dongwook Kim5Mu-Hyun Baik6Phil Ho Lee7Department of Chemistry, Kangwon National UniversityDepartment of Chemistry, Kangwon National UniversityDepartment of Chemistry, Korea Advanced Institute of Science and Technology (KAIST)Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST)Department of Chemistry, Kangwon National UniversityDepartment of Chemistry, Korea Advanced Institute of Science and Technology (KAIST)Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST)Department of Chemistry, Kangwon National UniversityAbstract We report a transition metal-catalyzed ring expansion of azulene that can be contrasted with C–H functionalization. This study represents the first example of the successful ring expansion of azulene using Cu(hfacac)2 (hfacac: hexafluoroacetylacetonate) with a diazo reagent. This result is notable for extending the Buchner reaction, previously limited to benzenoid aromatics, to nonbenzenoid compounds. The chemoselectivity of the reaction can be directed towards C–H functionalization by substituting the Cu catalyst with AgOTf. This approach does not require the addition of phosphine, NHC, or related ligands, and prefunctionalization of azulenes is unnecessary. Furthermore, the method exhibits excellent functional group tolerance, allowing for the synthesis of a wide range of 6,7-bicyclic compounds and C–H functionalized azulenes. We also present a theoretical study that explains the experimental observations, explaining why copper afford the ring expansion product while silver forms the C–H alkylation product.https://doi.org/10.1038/s41467-023-43200-7 |
| spellingShingle | Sangjune Park Cheol-Eui Kim Jinhoon Jeong Ho Ryu Chanyoung Maeng Dongwook Kim Mu-Hyun Baik Phil Ho Lee Selective ring expansion and C−H functionalization of azulenes Nature Communications |
| title | Selective ring expansion and C−H functionalization of azulenes |
| title_full | Selective ring expansion and C−H functionalization of azulenes |
| title_fullStr | Selective ring expansion and C−H functionalization of azulenes |
| title_full_unstemmed | Selective ring expansion and C−H functionalization of azulenes |
| title_short | Selective ring expansion and C−H functionalization of azulenes |
| title_sort | selective ring expansion and c h functionalization of azulenes |
| url | https://doi.org/10.1038/s41467-023-43200-7 |
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