1998 Fiscal Year Final Research Report Summary
Synthesis of novel tetradentate ligands with helical chirality and their application to catalytic asymmetric reactions
| Project/Area Number |
09650934
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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 |
有機工業化学
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
MIZUTAMI Tadashi Kyoto University, Graduate School of Engineering, Associate Professor, 工学研究科, 助教授 (40229696)
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| Project Period (FY) |
1997 – 1998
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| Keywords | optically active helical molecule / polymerization / stereoselectivity / screw-sense selection / binaphthylpalladium / poly (quinoxaline) / diisocyanobenzene |
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| Research Abstract |
Aromatizing polymerization of 1 , 2-diisocyanobenzene derivatives was mediated by optically active organopalladium(II) complexes bearing 1,1 -binaphth-2-yl groups to give optically active poly(quinoxaline-2,3-diyl)s with varying screw-sense selectivities, which crucially depended upon the substituents on the binaphthyl groups. The most effective catalyst, which has 7 -methoxy- 1,1 binaphthyl group, induced the formation of a single screw-sense. In contrast, a catalyst with 2 methoxy-l, l -binaphthyl group only afforded polymers with less than 20% screw-sense selectivity. In the cases of parent l, l'-binaphthyl and 2'-tert-butyldimethylsiloxy-l, l -binaphthyl derivatives, the selectivities ranged from 63% ee to 84% ee Isolation and structural analyses (single-crystal X- ray diffraction and ^1H NMR spectroscopy) of intermediary [oligo(quinoxalinyl)]palladium complexes revealed that the screw-sense selection in the polymerization may be decisively governed by the diastereomeric ratios of the (terquinoxalinyl)palladium(II) complex intermediate. The [oligo(quinoxalinyl)]palladium complexes were reacted with lithium diphenyiphosphide to give the corresponding [oligo(quinoxalinyl)]diphenylphosphine in reasonable yields. The optically active, helical tertiary phosphine was found to coordinate to palladium(II) in the reaction with allylpalladium chloride dimer to give the corresponding mono(phosphine)chloro(allyl)palladium(II) complexes.
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