2005 Fiscal Year Final Research Report Summary
Preparation of New Metallocene Ligands with Combined Chiralities and Their Application to Catalytic Asymmetric Synthesis
| Project/Area Number |
16550044
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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 |
Organic chemistry
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| Research Institution | Chuo University |
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Principal Investigator |
FUKUZAWA Shin-ichi Chuo University, Faculty of Science and Engineering, Professor, 理工学部, 教授 (50173331)
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| Project Period (FY) |
2004 – 2005
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| Keywords | ferrocene / bisferrocene / diamine / asymmetric transfer hydrogen / pinacol coupling / oxazoline / diol / cycloaddition |
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| Research Abstract |
The treatment of (R,R)-1,2-bis[(1-acetoxy)phenylmethyl]ferrocene with azidotrimethylsilane in CH_2Cl_2 in the presence of a catalytic amount of a Lewis acid such as Cu(OTf)_2 and Sc(OTf)_3, gave, the major (R,R)-isomer as major product with a minor meso-(R,S)-isomer. The optically active ferrocenyl diazide could be converted into the corresponding ferrocenyl diamine by reduction with LiAlH_4, and its ditosylamide and diacetamide were isolated as stable compounds. The ferrocenyl diamine and diamides were applied to ligands for the ruthenium complex catalyzed asymmetric transfer hydrogenation of aryl ketones and the complex with ferrocenyl diamine gave 1-arylethanols in good yields with up to 75% ee.
The pinacol coupling reaction of planar chiral ortho-oxazoline substituted formylferrocene by SmI_2 gave a mixture of three diastereomers of 1,2-diferrocenyl-1,2-diols; (R,R):(S:S):(R:S)=24:31:45. The tree diastereomers could be isolated by column chromatography, and their stereochemistries were confirmed by X-ray diffraction analysis. The use of divalent samarium triflate "Sm(OTf)_2", which was prepared by reduction of Sm(OTf)_3 with s-BuLi, remarkably improved the selectivity for the (R,R) isomer with 50% de. The combination of Yb(OTf)_3 and the (R,R)-ferrocenyl diol was revealed to be a good catalyst for the asymmetric Diels-Alder reaction of 3-acyloxazolidinone with cyclopentadiene, and the endo adduct was produced in up to 80% ee.
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Research Products
(8 results)
