2005 Fiscal Year Final Research Report Summary
Atom Efficient Generation of Transition Metal-Carbenoids and Its Application
| Project/Area Number |
16350052
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | KYOTO UNIVERSITY |
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Principal Investigator |
OHE Kouichi Kyoto University, Engineering, Professor, 工学研究科, 教授 (90213636)
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| Co-Investigator(Kenkyū-buntansha) |
OKAZAKI Takao Kyoto University, Engineering, Assistant Professor, 工学研究科, 助手 (90301241)
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| Project Period (FY) |
2004 – 2005
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| Keywords | carbene complex / carbene transfer reaction / catalytic reaction / ring-opening reaction / substitution reaction / isomerization / metallotropic shift |
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| Research Abstract |
We have developed a new route to carbene complexes such as (2-furyl) carbne and vinylcarbene complexes from alkynes possessing nucleophilic moieties and demonstrated several efficient catalytic reactions involving such carbene species. This methodology can be applied to catalytic insertion reactions into several X-H sigma bonds and catalytic ring-opening reactions with heteroaromatic compounds as intermolecular carbene transfer reactions.
When reactions of (Z)-β-ethynyl-α,β-unsaturated carbonyl compounds with alcohols and aromatic amines were carried out in the presence of a catalytic amonunt of [Rh(OAc)_2]_2 (2.5mol%) at room temperature, 2-furylmethyl alkyl ethers or N-(2-furylmethyl)-N-arylamines were obtained in fair to good yields. These results suggest that the carbene center of a (2-furyl)carbene-rhodium complex as reactive intermediates generated from (Z)-β-ethynyl-α,β-unsaturated carbonyl compounds inserts into O-H and N-H bonds. Similar catalytic insertion reactions take place
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with a C-H bond of allylic hydrocarbons.
We have recently found the in situ generation of vinylcarbene complexes by treatment of tert- and sec-propargyl carboxylates with transition metal catalysts. We found that the reaction of tert-propargyl acetates with furanes in the presence of [RuCl_2(CO)_3]_2(2.5mol%) affords a ring-opening or a substitution product in fair to good yield. We clarified the scope and limitations of the new catalytic carbene transfer reactions.
Further investigation of catalytic reactions involving ruthenium-vinylcarbene complexes led us to find the rearrangement of carbene complexes leading to the catalytic isomerization of conjugated oligoynes. We demonstrated the 1,3- or 1,5-metallotropic shift of carbene center to remote position of in conjugated oligoynes having propargyl acetate as a carbene trigger. A ruthenium comlex, [RuCl_2(CO)_3]_2 catalyzes isomerization of diynes and a triyne via generation of ruthenium-vinylcarbene complexes followed by carbene rearrangement, leading to dienynes and a dienediyne, respectively. Less
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