2000 Fiscal Year Final Research Report Summary
Novel Reactivity of Main Group Alkynylmetals and Its Application to Organic Synthesis
| Project/Area Number |
11650892
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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 | Kyoto Institute of Technology |
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Principal Investigator |
HARADA Toshiro Kyoto Institute of Technology, Faculty of Engineering and Design, Associate Professor, 工芸学部, 助教授 (30135628)
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| Project Period (FY) |
1999 – 2000
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| Keywords | Alkyne / Alkynylmetal / Tandem Cyclization / Cycloisomerization / C-H Insertion / Carbon-carbon Bond Formation / Main Group Metal / Carbenoid |
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| Research Abstract |
1-Alkynyl organometallics of main group metals have been frequently used as efficient carbon nucleophiles in organic syntheses. They react with a variety of electrophilic reagents generally at the carbon α to the metal atom. In order to develop a convergent method for the construction of complex carbon frameworks, a hitherto unexplored nucleophilic reactivity of alkynylmetals at the β position is investigated. The study reveals that various alkynylmetals react at the β position especially in intramolecular reactions. Alkynylzincates bearing a remote leaving group undergo smooth exo-cyclization at the β position with simultaneous 1, 2-migration of a ligand on the zinc atom to give 1-(cycloalkylidene) alkylzinc reagents, which can be used in subsequent reactions with electrophiles. Alkynylmetals of lithium, sodium, and potassium also undergo exo-cyclization to give cycloalkylidene carbene. A method for the synthesis of polycyclic compounds is developed utilizing the exo-cyclization of alkynylmetals and intramolecular C-H insertion of the resulting carbenes.
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