2007 Fiscal Year Final Research Report Summary
Study of Chiral Ligand Containing Thioether as Additional Stereochemical Control Element in Metal-Catalyzed Enantioselective Processes
| Project/Area Number |
18550091
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Synthetic chemistry
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| Research Institution | Niigata University |
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Principal Investigator |
HOSHI Takashi Niigata University, Institute of Science and Technology, Assistant Professor (20303175)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Chiral Ligand / Thioether Ligand / Catalytic Asymmetric Reaction / Asymmetric Allylic Alkylation / Indole / Asymmetric Diels-Alder Reaction / Palladium Catalyst / Cross-Coupling Reaction |
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| Research Abstract |
Trans influence of the chiral non-C2 symmetrical bidentate ligands containing strong and weak donor heteroatom pairs has proven to be a powerful control element in transition metal-catalyzed enantioselective processes. Among such ligands, thioether-containing phosphine ligands (P, S-mixed Ligand) have recently attracted growing attention because catalysts bearing them have the ability to generate an extra chiral center at the sulfur upon coordination (sulfur chirality) as an additional control element. I previously reported the synthetic study of (R)-2-diphenylphosphino-2'-phenylthio-1,1'-binaphthyl (S-MOP) as the P,S-mixed counterpart of BINAP in which 2-bromo-2'-diphenylphosphinyl-1,1'-binaphthyl 1 is intervened as a key intermediate for the electrophilic sulfenylation in the ligand synthesis. This intermediate would serve as a mono-phosphorus template providing structural diversity of the sulfur subunit of S-MOP ligand, however, its lithiated nucleophile must consider potential race
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mization of its axial chirality even at low temperature. In this study, to circumvent the aforementioned drawback, I have developed 2-bromo-2'-phenylthio-1,1'-binaphthyl 2 as the alternative synthetic intermediate, which would also serve as a mono-sulfur template providing an array of the phosphorus subunits of S-MOP ligand. I also applied S-MOP to palladium-catalyzed asymmetric allylic alkylations and Diels-Alder reactions and afforded good to excellent enantioselectivities. In addition, during the course of the study of the development of the palladium catalyst, I have developed a novel biphenylene ring-containing ruthenocene-based phosphine, R-Phos, as a supporting ligand for palladium-catalyzed Suzuki-Miyaura reactions of aryl chlorides with arylboronic acids. In particular, at a 1:3 Pd:R-Phos ratio, substrate combinations even for the construction of highly hindered tetra-ortho-substituted biaryls can be achieved in good to excellent yields with low catalyst loadings in short reaction times. Less
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[Journal Article] Biphenylene-Substituted Ruthenocenylphosphine for Suzuki-Miyaura Coupling of Aryl Chlorides2008
Author(s)
Takashi, Hoshi, Taichi, Nakazawa, Ippei ,Saitoh, Ayako, Mori, Toshio, Suzuki, Jun-ichi, Sakai, Hisahiro, Hagiwara
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Journal Title
Organic Letters 10(10)
Pages: 2063-2066
Description
「研究成果報告書概要(欧文)」より
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[Presentation] Development of 2-Diphenylphosphino-2'-phenylsulfenyl-1,1'-binaphthyl(S-MOP) as Chiral P,S-Ligand: Application to Pd-Catalyzed Asymmetric Allylic Substitution2007
Author(s)
Takashi, Hoshi, Shun, Sato, Toshio, Suzuki, Hisahiro, Hagiwara
Organizer
54th Symposium on Organometallic Chemistry, Japan
Place of Presentation
Hiroshima
Year and Date
20071027-28
Description
「研究成果報告書概要(欧文)」より
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