Asymmetric Alkylation ofIminium Ion Based on Control of Dynamic Stereochemistry
| Project/Area Number |
15550094
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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 | Nagasaki University |
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Principal Investigator |
ONOMURA Osamu Nagasaki University, Graduate School of Biomedical Sciences, Associate Professor, 大学院・医歯薬学総合研究科, 助教授 (60304961)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,800,000 (Direct Cost: ¥3,800,000)
Fiscal Year 2004: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2003: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | iminium ion / asymmetric alkylation / copper / bisoxazoline / dynamic complex / optically active / piperidine / regioselective |
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| Research Abstract |
Catalytic asymmetric alkylation of iminium ions, which were generated from α-methoxylated piperidines and β,γ-unsaturated piperidines electrochemically prepared from N-protected piperidines, has been developed.
1.In the presence of a catalytic amount of Cu(OTf)_2 and chiral bisoxazoline ligand, at room temperature the reaction of β,γ-unsaturated α-methoxy-N-4-methoxybenzoylpiperidine 2 and dimethyl malonate gave a-substituted piperidine in moderate enantioselectivity (50%ee).
2.Using diphenyl malonates as nucleophiles in the reactions with 2 gave orsubstituted piperidine with high enantioselectivities (up to 95%ee).
3.Methyl acetoacetate reacted with α-methoxy-N-4-methoxybenzoylpiperidine 1 at 0℃ to give α-substituted piperidine in 65%ee. Also, the reaction of methyl acetoacetate and 2 at -20℃ afforded α-substituted piperidine in 80%ee.
4.The reaction of β-ethyl-β,γ-unsaturated-α-methoxypiperidine and methyl acetoacetate proceeded at room temperature to give γ-substituted piperidine in moderate enantioselectivity (45%ee). In this case MOC group was the most suitable for N-protecting group.
5.These products could be transformed into optically active (2-piperidyl)acetic acid and methyl cincholoiponate, which are key intermediates for syntheses of bioactive compounds.
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Report
(3 results)
Research Products
(10 results)
