Synthesis and Properties of Polycatenane, A Dream Polymer

对于聚链烷的合成，以下三个步骤是必不可少的：（i）使用链烷作为单体，（ii）通过协同反应进行环化，以及（iii）桥键的定量裂解。研究了利用6π-周环电子环化反应作为协同环化反应。通过α，β-不饱和酮的McMurry偶联反应制备了三烯。芳香酮衍生的三烯很不稳定，而脂肪酮衍生的三烯容易处理。进行所得三烯的热环化。虽然中心双键为顺式构型的三烯被定量环化，但反式异构体保持不变。因此，环化反应在烯烃异构化条件下进行。而高压汞灯照射或自由基源的加入会导致三烯体系的降解。异构化反应 ...更多信息 为了避免不希望的反应如聚合反应，非常温和的条件是必要的。研究了作为协同环化反应的Diels-Alder反应所得到的环体系的断裂。研究了具有两个邻位酯基的碳-碳单键的还原断裂，虽然在环系统中没有观察到断裂。由于将菌株引入环系统可能降低Diels-Alder反应的效率，因此这种系统不适合于聚链烷合成。因此，通过偶氮化合物作为亲双烯体的杂Diels-Alder反应获得的环系统的断裂进行了研究。虽然富电子氮-氮键的断裂效率较低，但缺电子氮-氮键的定量断裂是可能的。因此，索烃单体必须具有反应活性且相当不稳定的偶氮二羰基。为了进行这种可以原位氧化制备的索烃的杂狄尔斯-阿尔德反应，进行了具有两个1，3-二烯基团的大环的合成。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