| 研究課題/領域番号 |
20K15269
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| 研究機関 | 北海道大学 |
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研究代表者 |
REYES RONALD・LAZO 北海道大学, 化学反応創成研究拠点, 特任助教 (30845475)
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| 研究期間 (年度) |
2020-04-01 – 2023-03-31
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| キーワード | asymmetric synthesis / borylation / organometallic catalysis / organic synthesis / C-H activation / C-H functionalization |
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| 研究実績の概要 |
With our interest in the development of novel methodologies for the transformation of C-H bonds in readily available feedstock chemicals, we previously demonstrated the competent activation and subsequent asymmetric borylation of gamma-C(sp3)-H bonds under Ir catalysis. Our collaboration with ICReDD scientists has given us infinite opportunity to further extend the reactivity of our catalytic system.
Furthermore, using our catalytic system we have developed a strategy for the asymmetric desymmetrization of monocyclic saturated ring systems in pharmacologically-relevant heteroarenes including pyridine, quinoline, isoquinoline, and benzo-annulated N-heteroaryl frameworks facilitating the preparation of cycloalkane organoboron derivatives appended on common natural product, bioactive, and medicinally significant heterocyclic cores.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
As described, several important paper contributions have been made. Thus, guided by calculation derived transition-state models, we recently succeeded in the asymmetric borylation of more distal C-H bonds in the aliphatic hydrocarbon chain of common and readily available chemical feedstocks including biomass resources allowing for a more sustainable and efficient organic synthesis. Thereby, the borylation of epsilon-C-H bonds, located five carbons away from the carbonyl group of the substrate, has been achieved - a direct functionalization realized using a modularly designed supramolecular catalytic assembly.
Moreover, an enantioselective desymmetrization of monocyclic saturated ring systems using a chiral Ir-monophosphite catalyst through a directed C(sp3)-H borylation was developed. The methodology provides access to enantioenriched cycloalkane boronate derivatives encompassing synthetically significant small to intermediate-sized rings from cyclopropane to cycloheptane. The catalytic system efficiently discriminates between methylene C-H bonds located on two different prochiral carbon centers leading to the generation of highly desired structural cycloalkane motifs bearing contiguous chiral centers. Further transformations of the cycloalkane boronate products were also demonstrated
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| 今後の研究の推進方策 |
It is my plan and goal to conclude and publish our work on the asymmetric desymmetrization of cycloalkyls appended unto privileged heterocyclic cores. This project has been started last year and I believe that our findings merit publication at this stage. Moreover, for the year 2022, I am working on the development of a supramolecular catalytic system consists of a metal catalyst and chiral ligand platform in generating an asymmetric field or a substrate binding cavity that will enable the activation and functionalization of remote C-H bonds.
Our project collaboration in ICReDD is on-going and it looks into the possibility of achieving site-selectivity and stereocontrol in C-H bond activation by carefully considering catalyst design combining experimental, theoretical, and information science. We envisioned that computational information will help to expedite the development of effective catalyst to realize our goal in functionalizing remote C-H bonds in readily available starting materials such as hydrocarbon derivatives, fatty acids, and bioactive compounds. This strategy will provide a unifying theme for the diversification of molecules generating 3D complexities to enable facile access to important compounds.
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| 次年度使用額が生じた理由 |
Due to the onset and continuous surge of COVID-19 pandemic several conferences were cancelled. Laboratory spending is likewise affected due to some restrictions enforced to prevent the spread of the infection. For the next fiscal year, research activities will be promptly continued. Research expenses will be devoted in purchasing necessary chemicals for reaction optimization. Essential equipment and glassware will be purchased in line with the need of the research. Attendance in prominent conferences will also be prioritized.
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