| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2017: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2015: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
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| 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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