| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2006: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2005: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
For the synthesis of polycatenane, the following three steps are essential : (i) the use of catenane as the monomer, (ii) cyclization by concerted reaction, and (iii) the quantitative cleavage of the bridging bonds. The utilization of 6π-pericyclic electron-cyclization reaction as the concerted cyclization reaction was investigated. McMurry coupling reaction of α,β-unsaturated ketones were carried out to prepare trienes. The trienes derived from aromatic ketones were very unstable while those derived from aliphatic ketones can be treated easily. The thermal cyclization of the resulting trienes was carried out. Although the triene in which the central double bond has the cis-configuration cyclized quantitatively, the trans-isomer remained unchanged. Therefore, the cyclization was carried out under the olefin-isomerization condition. However, irradiation by the high pressure mercury lamp or the addition of radical source caused the degradation of the triene system. The isomerization unde
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r the very mild condition is necessary to avoid the undesired reactions such as polymerization. The cleavage of the ring system obtained by the Diels-Alder reaction as the concerted cyclization reaction was investigated. The reductive cleavage of carbon-carbon single bond that has two vicinal ester groups was investigated although no cleavage was observed without the strain in the ring-system. Since the introduction of the strain to the ring-system may reduce the efficiency of the Diels-Alder reaction, such a system is unsuitable for the polycatenane synthesis. Thus, the cleavage of the ring-system obtained by the hetero Diels-Alder reaction of azo compounds as the dienophile was investigated. Although the cleavage of electron-rich nitrogen-nitrogen bonds underwent in low efficiency, the quantitative cleavage of electron-defficient nitrogen-nitrogen bond was possible. Therefore, catenane monomer must have the azodicarbonyl group that is reactive and rather unstable. To carry out the hetero Diels-Alder reaction of such catenane that can be oxidatively prepared in situ, the synthesis of macrocycle that has two 1,3-diene groups was carried out. Less
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