2018 Fiscal Year Annual Research Report
Dearomative Functionalization of Arenes by Half-Sandwich Rare-Earth Catalyzed C‒H Additions
| Project/Area Number |
18F18338
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| Research Institution | Institute of Physical and Chemical Research |
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Principal Investigator |
侯 召民 国立研究開発法人理化学研究所, 開拓研究本部, 主任研究員 (10261158)
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| Co-Investigator(Kenkyū-buntansha) |
LI WEI 国立研究開発法人理化学研究所, 開拓研究本部, 外国人特別研究員
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| Project Period (FY) |
2018-11-09 – 2021-03-31
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| Keywords | Organic Synthesis / Dearomatization / η6-Arene Complexes / Rare-earth Catalysis / Asymmetric Catalysis / C-H activation |
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| Outline of Annual Research Achievements |
The dearomatization reactions provide a direct entry into complex alicyclic synthetic building blocks from simple and abundant sources of (hetero) arenes, which is considered as a unique and useful synthetic strategy in organic synthesis. Our purpose of the proposed research is to develop novel (enantioselective) dearomative functionalizations of arenes via nucleophilic additions to η6-arene complexes. By introducing new and mild carbanion nucleophiles, we want to achieve broad substrate scope and good functional group tolerance, and thus enable the applications of the developed methodologies to the synthesis of drugs and natural products.
Based on the successful activation mode of pyridines with half-sandwich rare-earth alkyl complexes developed by our group, we plan to investigate the dearomative arylation of arenes via Csp2-H additions of pyridines to η6-arene complexes.
In the last 4 months, we have investigated the dearomative arylation of (η6-arene)Cr(CO)3 via Csp2-H additions of pyridines to η6-arene complexes catalyzed by half-sandwich rare-earth complexes. Two types of (η6-arene)Cr(CO)3 were synthesized and tried in this reaction. Also other conditions like solvents, reaction temperatures and different half-sandwich rare-earth complexes were investigated. So far, no good results about dearomative arylation of (η6-arene)Cr(CO)3 were obtained. However, we observed some ligand exchanging reaction by using PPh3 as the additive. More reaction conditions should be conducted.
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| Current Status of Research Progress |
Current Status of Research Progress
3: Progress in research has been slightly delayed.
Reason
We investigated the dearomative arylation of (η6-arene)Cr(CO)3 via Csp2-H additions of pyridines to η6-arene complexes catalyzed by half-sandwich rare-earth complexes. Two types of (η6-arene)Cr(CO)3 were synthesized and tried in this reaction. Also other conditions like solvents, reaction temperatures and different half-sandwich rare-earth complexes were investigated. So far, no good results about dearomative arylation of (η6-arene)Cr(CO)3 were obtained. However, we observed some ligand exchanging reaction by using PPh3 as the additive.
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| Strategy for Future Research Activity |
First, we will try more reaction conditions including solvents, temperature, additives.
Second, we will do some modification on the η6-arene complexes like changing the metal or the ligands.
Third, we plan to synthesize some new half-sandwich rare-earth complexes to promote the reaction.
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Research Products
(4 results)
