利用酵素解析法來合成掌性新型骨架之四氧四縮醛含氧籠狀化合物

Abstract

本論文針對新型骨架的掌性含氧籠狀化合物U-2作系統性的研究，分為三部份。 首先，我們利用酵素解析法先得到具有光學活性的起始物(-)-7和(+)-7 (>99% e.e.)，之後經臭氧裂解合成出具有光學活性的含氧籠狀化合物(+)-10和(-)-10，再經由不同取代基的轉換，至終我們可以得到化合物U-2的兩個具光學活性且彼此為鏡像的含氧籠狀化合物(-)-17和(+)-17。 接著，我們從化合物U-2產率的增加，得知在臭氧裂解反應完成後加入酸性樹脂(Amberlyst-15)，能有助於反應中間物24環化地完全。 最後，我們藉著在臭氧裂解反應中控制臭氧通入的當量，可以初步瞭解化合物U-2生成的反應機構。即二環戊二烯上的兩個雙鍵在臭氧裂解反應進行時，norbornene上的雙鍵會被高選擇性地率先裂解開。

Here we have done the systematic research about the novel chiral oxa-cage U-2, and this work can be divided into three parts. First, we utilize enzymatic resolution to obtain the optical active starting material (-)-7 and (+)-7 (>99%). And after ozonolysis of them, we can afford the optical active oxa-cage compounds (+)-10 and (-)-10. Then we have accomplished several transformations with different substituents on the skeleton. At the end , we obtain two optical active compounds (-)-17 and (+)-17, which are the enantiomeric pair of U-2. Second, ozonolysis of the dicyclopentadiene, followed by addition of Amberlyst-15, can help the complete cyclization to afford the tetraoxa-cage compound with higher yield. Finally, by taking control of the amount of entering O3 in ozonolysis, we understand the reaction mechanism from U-1 to U-2 at the first stage. That is , in the progress of ozonolysis, the double bond of norbornene react with ozone with high selectivity.