2006 Fiscal Year Final Research Report Summary
Efficient Organic Reactions by Dynamic Control of Early Transition Metal Complexes
| Project/Area Number |
14078219
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Okayama University |
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Principal Investigator |
TAKAI Kazuhiko Okayama University, Graduate School of Natural Science and Technology, Division of Chemistry and Biochemistry, Professor, 大学院自然科学研究科, 教授 (00144329)
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| Project Period (FY) |
2002 – 2005
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| Keywords | Chromium / Tantalum / Rhenium / Alkylidene complex / Alkyne complex / C-H bond activation / Atom-economical process / Iodocyclopronane |
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| Research Abstract |
1. Selective Transformations with Novel Organochromium Species : The family of trans-iodocyclo-propanes are good precursors for constructing cyclopropyl-cyclopropyl and-vinyl carbon skeletons. We have found that iodocyclopropanation of terminal alkenes proceeds with organochromium species generated by chromium(II)-reduction of iodoform in the presence of TEEDA (N,N,N',N'-tetraethylethylenediamine) under high stereocontrol. The transformation proceeds smoothly without the presence of a hydroxy or an alkoxy group near the double bond, which is necessary for the cyclopropanation of iodoalkenes with zinc carbenoids.
2. Synthesis and Reactions of Tantalum η^2-Bis(trimethylsilyl)acetylene Complex : A tantalum-alkyne complex TaCl_3(Me_3SiC≡CSiMe_3)(dme) (1, DME=1,2-dimethoxyethane) is synthesized by treatment of the corresponding alkyne with a low-valent tantalum derived by reduction of TaCl_5 with zinc in a mixed solvent of toluene and DME according to our previously reported procedure. The t
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antalum complex 1 reacts with an internal alkyne to give a corresponding alkyne complex via ligand exchange reaction. The mechanism of the ligand exchange is clarified by kinetic study of the formation of diphenylacetylene complex from 1 and diphenylacetylene.
3. Carbon-Hydrogen Bond Activation with Rhenium Catalysts and Its Application to Organic Synthesis : A rhenium complex, [ReBr(CO)_3(thf)]_2, catalyzes the reaction of an aromatic aldimine with an isocyanate and an acetylene to give a phthalimidine and an indene derivative in a quantitative yield, respectively. The reactions proceed via C-H bond activation, insertion of the isocyanate or the acetylene, intramolecular nucleophilic cyclization to the aldimine of the generated amido-or alkenyl-rhenium species, and reductive elimination. In contrast to ruthenium and rhodium catalysts, which are usually employed in this type of reaction, the rhenium catalyst promotes the insertion of a polar unsaturated molecule. The rhenium-catalyzed reaction of an aromatic ketimine with ethyl acrylate gave an indene derivative in good yield via C-H bond activation. The indene derivatives could also be obtained by the reactions of aromatic ketones with α,β-unsaturated esters in the presence of catalytic amounts of the rhenium complex andp-anisidine. Less
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[Journal Article] Preparation, Structural Characterization, and Reactions of Tantalum-Alkyne Complexes TaCl_3(R^1C〓CR^2)L_2 (L_2=DME, Bipy, and TMEDA ; L=PY)2003
Author(s)
T.Oshiki, K.Tanaka, J.Yamada, T.Ishiyama, Y.Kataoka, K.Mashima, K.Tani, K.Takai
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Journal Title
Organometallics 22巻3号
Pages: 464-472
Description
「研究成果報告書概要(和文)」より
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[Journal Article] Preparation, Structural Characterization, and Reactions of Tantalum-Alkyne Complexes TaCl3(R1C≡CR2)L2 (L2 = DME, Bipy, and TMEDA; L = Py)2003
Author(s)
T.Oshiki, K.Tanaka, J.Yamada, T.Ishiyama, Y.Kataoka, K.Mashima, K.Tani, K.Takai
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Journal Title
Organometallics 22
Pages: 464-472
Description
「研究成果報告書概要(欧文)」より
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