2017 Fiscal Year Final Research Report
Asymmetric Synthesis of Dibenzohelicenes via Nickel-Catalyzed Intramolecular Cyclization of Triynes Using Helically Chiral Polymer Ligands
Project/Area Number |
15K05499
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Research Field |
Synthetic chemistry
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Research Institution | Kyoto University |
Principal Investigator |
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Project Period (FY) |
2015-04-01 – 2018-03-31
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Keywords | ヘリセン / 不斉合成 / 高分子触媒 / らせん高分子 / ニッケル触媒 / らせん不斉 |
Outline of Final Research Achievements |
In the presence of poly(quinoxaline-2,3-diyl)-based helically chiral phosphine ligand (PQXphos), nickel-catalyzed intramolecular [2+2+2] cycloisomerization of triynes afforded optically active dibenzohelicenes with higher enantioselectivities than those of low-molecular-weight chiral phosphine ligands. Reversal of the enantioselectivity of PQXphos was investigated by changing the substituents on the phosphorous atom. Although (P)-PQXphos bearing phenyl group afforded (-)-helicenes up tp 86% ee, (P)-PQXphos bearing 4-ethoxyphenyl group afforded enantiomeric (+)-helicenes up to 91% ee. The obtained chiral dibenzo[6]helicenes showed circular dichroism spectra and circular polarized luminescence properties based on the helical structure. The absolute configuration of chloro-substituted dibenzo[6]helicene was determined by single crystal X-ray structure analysis.
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Free Research Field |
触媒化学
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