Synthesis and Properties of Polycatenane, A Dream Polymer

对于聚连环烷的合成，以下三个步骤是必不可少的：(i)使用连环烷作为单体，（ii）协同反应环化，（iii）桥键的定量切割。研究了6π-周环电子环化反应作为协同环化反应的应用。采用α、β-不饱和酮的McMurry偶联反应制备了三烯。芳香族酮衍生的三烯非常不稳定，而脂肪族酮衍生的三烯很容易处理。得到的三烯进行了热环化反应。虽然中心双键具有顺式构型的三烯被定量环化，但反式异构体保持不变。因此，在烯烃异构化条件下进行环化反应。但高压汞灯照射或自由基源的加入会导致三烯体系的降解。更有必要在非常温和的条件下进行异构化，以避免聚合等不良反应的发生。研究了Diels-Alder反应作为协同环化反应所产生的环系裂解。研究了具有两个相邻酯基的碳-碳单键的还原断裂，但在环系中没有观察到断裂。由于在环体系中引入应变可能会降低Diels-Alder反应的效率，因此这种体系不适合合成聚己烷。因此，本文研究了偶氮化合物作为亲二酚的异Diels-Alder反应所产生的环系的裂解。富电子氮-氮键的解理效率较低，而缺电子氮-氮键的定量解理是可能的。因此，链烷单体必须具有反应性强且相当不稳定的偶氮二羰基。为了使这种可就地氧化制备的连环烷进行杂Diels-Alder反应，合成了具有两个1,3-二烯基团的大环。少

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 … More 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