| 摘要: | 酚-甲醛環狀聚合物(Calixarenes) 含有分子內中空，因此，有機小分子或金屬離子可能會進入此一分子內中空，而形成所謂的”主客化合物”。這一個特殊的現象在化學界上，已被廣泛的應用於酵素模擬、金屬離子分離、和微量檢驗的研究之上。在本實驗室先前所規劃的研究計劃中，嘗試以一個四步驟的合成途徑，來製備出文獻中未曾報導過的1,2-鄰位雙烷基醚化之calix[4]arenes。本實驗室現已完成了計劃內全部的1,2-鄰位雙烷基醚化之calix[4]arenes 的製備和鑑定，且其成果已分別發表於 Tetrahedron (2011, 67, 3238-3247. and 2011, 67, 3936-3944.)。在合成的途徑中，本實驗室發現在進行第二醚化時，分子內的苯甲酸酯基有轉移現象的發生。因此這一個研究計劃的前期，便是研究1-單烷基醚化-3-單苯甲酸酯化之 calix[4]arenes，在未加入鹵化烷類的反應條件下，進行分子內苯甲酸酯基的轉移可行性。本實驗室判斷，在K2CO3 的反應條件下，化合物應會進行分子內苯甲酸酯基的轉移，而生成1-單烷基醚化-2-單苯甲酸酯化之calix[4]arenes 產物；研究計劃的第二期，則是進一步利用具拉電子性-NO2 的苯甲酸酯官能團，或具推電子性-OCH3 的苯甲酸酯官能團，來取代原來的單苯甲酸酯化取代，並針對這三種不同的1-單烷基醚化-3- 單苯甲酸酯化之calix[4]arenes 的產物，來進行苯甲酸酯基轉移的熱力學和動力學上研究；而研究計劃的第三期，則是針對苯甲酸酯基轉移後的產物，1-單烷基醚化-2-單苯甲酸酯化之calix[4]arenes，進行第二酯化或第二醚化反應，進而去了解在calix[4]arene 的系統中，已存在之單烷基醚化取代或單苯甲酸酯化取代，對第二酯化或第二醚化反應的位置選擇性；這一個研究計劃同時希望能證實，本實驗室所提出之分子內苯甲酸酯基轉換的反應機構。
A class of cavity-containing phenol-formaldehyde cyclic oligomers, also known as calixarenes, is able to occlude a small molecule and/or metal ion to form a “host-guest” complex. In our recent investigation, we had proposed and under-taken two multi-step synthetic routes for the 1,2-dialkoxycalix[4]arenes, and we had successfully synthesized and characterized all the proposed 1,2-dialkoxycalix[4]arene products. The results were published on Tetrahedron (2011, 67, 3238-3247. and 2011, 67, 3936-3944.) During the study of those synthetic routes, we were surprised to find that the intramolecular benzoyl-migration was occurred during the second etherification step and yielded the unexpected 1,3-dialkoxy products. Therefore, this three-year proposal is to investigate the intramolecular benzoyl-migration phenomena in 1-alkoxy-3-benzoyloxycalix[ 4]arene systems. We believed that the intramolecular benzoyl-migration would occur with and/or without the presence of alkyl halides in the second etherification step. Therefore, we believed that a new set of unsymmetrical 1-alkoxy-2-benzoyloxycalix[4]arene products, which have not been reported in the literature, would be afforded if the benzoyl migration of 1-alkoxy-3-benzoyloxycalix[4]arenes does occur in the absent of alkyl halides. We had also proposed a reaction mechanism for the migration of the benzoyl moiety, and would like to confirm the mechanism in this research project. We would also like to perform additional esterification and/or etherification on the 1-alkoxy-2-benzoyloxycalix[ 4]arenes, and the additional esterification and/or etherification results might reveal the regioselective behavior of the calix[4]arene systems. |
