2007 Fiscal Year Final Research Report Summary
Chiral dirhodium (II) catalysts: from carbene to nitrene and Lewis acids
| Project/Area Number |
17390001
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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 |
Chemical pharmacy
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| Research Institution | Hokkaido University |
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Principal Investigator |
HASHIMOTO Shunichi Hokkaido University, Faculty of Pharmaceutical Sciences, Professor (80107391)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Seiichi Hokkaido University, Faculty of Pharmaceutical Sciences, Associate Professor (90261320)
ANADA Masahiro Hokkaido University, Faculty of Pharmaceutical Sciences, Associate Professor (90344473)
NAMBU Hisanori Hokkaido University, Faculty of Pharmaceutical Sciences, Associate Professor (80399956)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Dirhodium (II) Complexes / α-Diazocarbonyl Compounds / Asymmetric catalysis / Carbenes / Nitrenes / Lewis acid catalysts / 1.3-Dipolar cycloadditions / hetero Diels-Alder reactions |
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| Research Abstract |
1. We have found that the enantioselective intramolecular C-H insertion reaction of α-alkyl-α-diazoacetates catalyzed by dirhodium tetrakis [N-phthaloyl-(S)-tert-leucinate], Rh_2(S-PTTL)_4, proceeded at-78℃ to provide exclusively cis-2-arylcyclopentanecarboxylate with up to 97% ee.
2. The Rh_2(S-TFPTTL)_4-catalyzed aziridination of acyclic silyl enol ethers with [N-(2-nitrophenylsulfonyl) imino] phenyliodinane [NsN=IPh] followed by treatment with aq. TFA provided α-amino ketone derivatives in high yields and enantioselectivities of up to 95% ee. The effectiveness of the present catalytic method was demonstrated by the enantioselective synthesis of (-)-metazocine as well as (-)-ritodrine. The amination of silylketene acetals derived from methyl phenylacetates with NsN=IPh under the catalysis of Rh_2(S-TCPTTL)_4 afforded phenylglycine derivatives in high yields and with up to 99% ee.
3. We found that Rh_2(S-BPTPI)_4, a dirhodium (II) carboxamidate complex which incorporates (S)-3-(benzene-fused-phthalimido)-2-piperidinonate as bridging ligands, is a highly efficient catalyst for endo- and enantioselective HDA reactions. The Rh_2(S-BPTPI)_4 catalytic system provides a great flexibility in the nature of aldehyde substrates as well as the substitution pattern on Danishefsky-type and monooxygenated dienes, wherein essentially perfect diastereoselectivity and high levels of enantioselectivity ranging from 90 to 99% ee have been achieved. The effectiveness of the present protocol has been demonstrated by the synthesis of cyclic diarylheptanoid natural products such as (-)-centrolobine, calyxin L
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Research Products
(58 results)
