2016 Fiscal Year Annual Research Report
Ｃ（ｓｐ３）－Ｈ及びＣ（ｓｐ）－Ｈ結合活性化を経るアルキニル化反応の開発．
| Project/Area Number |
16J11354
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| Research Institution | Kyoto University |
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Principal Investigator |
ZHAO QIANG 京都大学, 工学研究科, 特別研究員(DC1)
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| Project Period (FY) |
2016-04-22 – 2019-03-31
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| Keywords | carbene / C-H functionalization / rhodium / triazole / alkyne |
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| Outline of Annual Research Achievements |
We studied on a rhodium(II)-catalyzed reaction of N-sulfonyl-1,2,3-triazoles with 2-alkenols. The reaction is initiated by insertion of an α-imino carbene into the O-H linkage of alcohol, forming a 2-alkenoxy enamide intermediate. A thermal [3,3]-sigmatropic rearrangement follows to yield 2-substituted 2-amino ketone in a stereoselective manner. Finally, a successful application of this methodology to a formal synthesis of (-)-α-conhydrine was also studied.
We also developed a new kind of triazoles. We found that it could generate acceptor-acceptor rhodium carbene complex in the presence of rhodium catalyst. The in-situ generated acceptor-acceptor rhodium carbene complex could react with simple arenes, leading to the formation of enaminones via aromatic C-H functionalization.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
Reactions of carbenes substituted by two acceptor groups generated from 1,2,3-triazoles are yet to be reported. Here we found a rhodium(II)-catalyzed reaction of simple arenes with 4-acyl-1-mesyl-1,2,3-triazoles. Enaminones are synthesized via aromatic C-H functionalization with carbene species substituted with two acceptor groups. Interestingly, the reaction takes place exclusively at the aromatic C(sp2)-H bonds in the presence of benzylic C(sp3)-H bonds. Preliminary mechanistic study indicates an electrophilic aromatic substitution pathway via a zwitterionic intermediate rather than a concerted C-H insertion pathway.
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| Strategy for Future Research Activity |
In the following year, we are going to develop new reactions using our new developed 4-Acyl-1-mesyl-1,2,3-triazoles. As our new developed triazoles are classified as acceptor-acceptor carbenes which are different from previous reported triazoles. We hope, we can develop unique new reactions using our new triazoles which cannot do using previous reported triazoles.
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Research Products
(2 results)
