| Budget Amount *help |
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
1) Aminosilane Mediated 1,4-Nucleophilic Additions of Naked Aldehydes
Nucleophilic reaction of naked aldehydes have been quite limited because of the difficulty to generate enolates or enols of aldehydes. Masked aldehydes such as enamine or silylenol ether of aldehydes have been used for alkylation or conjugate addition of aldehydes so far. In this connection, we investigated on diethylaminotrimethylsilane mediated nucleophilic reactions of naked aldehydes which resulted in inter/intra molecular 1,4-conjugate addition to various electron deficient olefins such as vinylketone, methyl acrylate, vinylsulphone, and alpha-methylenecycloalkanone to give in good yields 5-ketoaldehydes which are important precursors for syntheses of substituted cyclohexenone derivatives.
2) Aminosilane Mediated 1,2-Nucleophilic Additions of Aldehydes
The aldehydes also underwent intermolecular seif-aldol condensation to give E-alpha, beta-unsaturated aldehydes in acceptable yields. Similarly, under the same reaction conditions dialdehydes provided cyclic aldols by intramolecular aldol condensation.
3) Aminosilane Mediated Tandem Nucleophilic Reaction of Aldehyde with Methyl 2,3-Dihalopropanoate
In the reaction of of 2,3-dihalopropanoate and aldehyde, cyclopropane carbaldehyde was obtained as a result of tandem Michael-alkylation, namely generation of methyl alpha-haloacrylate in situ followed by 1,4-conjugate addition of aldehyde to acrylate and subsequent intramolecular substitution.
4) Application to natural product synthesis
Diethylaminotrimethylsilane mediated conjugate addition of (R)-(+)-citronellal to methylvinylketone followed by intramolecular aldol condensation provided 4-substituted 2-cyclohexeneone derivative in 80% yield. Starting from the enone, phenylselenylation followed by methylation and subsequent PCC oxidation furnished aromatic sesquiterpenoid, (R)-(-)-curcumene.
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