2002 Fiscal Year Final Research Report Summary
Development of reactions based on addition of electrophiles to methylenebisphosphonates
| Project/Area Number |
12672053
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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 |
Chemical pharmacy
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| Research Institution | Kansai University (2001-2002)
Kyoto University (2000) |
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Principal Investigator |
NAGAOKA Yasuo Kansai University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (90243039)
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| Project Period (FY) |
2000 – 2002
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| Keywords | alkenylphosphonate / allene / chiral phosphine ligand / conjugate addition / conjugate reduction / vinyl anion / Michael reaction |
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| Research Abstract |
Allenes are recent focus of versatile class of intermediates in a variety of organic synthetic processes. We developed a novel method to synthesize allenes by successive Horner-Wadsworth-Emmons olefination starting from methylene-bisphosphonate and two carbonyl compounds. The key to success is KH or KH-18-crown-6 as a base for second HWE olefination of hydroxyalkenylphosphonates. Asymmetric allene synthesis based on this method is now in progress.
As our continuing studies of efficient synthetic application of lithium phosphonates, we have developed cyclization reaction of bis-alkenylphosphonate 1. Although the reaction of 1 with organolithium reagents afforded both tandem Michael cyclization products and α-deprotonation-cyclization products, the latter was selectively formed in high yield by simply treating 1 with LDA. Application of chiral bis-alkenylphosphonate 2 opens a simple synthetic way to chiral phosphine ligand 5. Treatment of 2 with LDA followed by electrophilic trapping of intermediate cyclic lithium phosphonate 3 with benzaldehyde afforded aldol-type adduct 4 in 54%. The alcohol 4 was transformed to 5 by 6 steps in 16% yield.
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Research Products
(28 results)
