1998 Fiscal Year Final Research Report Summary
Development of Chiral Ferrocenyl Compounds including Hetero Atoms and Their Use in Asymenetric Synthesis
| Project/Area Number |
09450340
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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 |
UEMURA Sakae Kyoto University, Engineering, Professor, 工学研究科, 教授 (70027069)
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| Co-Investigator(Kenkyū-buntansha) |
ITOH Osamu Kyoto University, Engineering, Research Assistant, 工学研究科, 助手 (10026023)
OHE Kouichi Kyoto University, Engineering, Associate Professor, 工学研究科, 助教授 (90213636)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Organic Diselenide / Selenocyclization / Alkenol / Unsaturated Carboxylic Acid / Alkenyl Urethane / Lactone / N-Heterocycle |
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| Research Abstract |
We have developed the methodology to introduce chilalities into organic molecules using chiral ferrocenylselenium reagents. These reagents are applicable to asymmetric synthesis of chiral compounds such as allenes, 4-alkyl-1-alkylidenecyclohexanes, b-hydroxyalkyl selenides, allylic alcohols, and allylic amines. In this report we present new methodology to prepare several heterocycles with a high stereoselectivity. Asymmetric intramolecular selenocyclization of alkenoic acids, alkenols, and alkenyl urethanes using optically active 2-[1-(dimethylamino)ethyl]ferrocenylselenenyl cations proceeds smoothly to give the corresponding organoselenenyl moiety containing lactones, cyclic ethers, and N-heterocycles, respectively, in good to excellent chemical yields (up to 97%) with very high diastereoselectivities (up to 98% de). The nature of counter anions of the selenenylating agents affected remarkably the diastereoselectivity of the cyclization, PF_6 and BE_4 being revealed to be the best for that of alkenoic acids and alkenols and that of alkenyl urethanes, respectively. The plausible reaction scheme for cyclization is presented where a chiral selenenylating agent approaches the carbon-carbon double bond of the substrate from the less bulky direction to afford a chiral episelenonium ion followed by an intramolecular back side attack of a nucleophile.
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