Study on Transition Metal-Catalyzed Reactions of a Highly Strained Alkyne and Its Application to the Synthetic Organic Chemistry

本项目重点研究了用过渡金属催化剂催化芳烃和杂芳烃等高应变炔的新反应。提出了一种钯催化双炔和芳炔[2+2+2]共环合成双芳炔的新方法。通过这种方法，各种芳基萘衍生物，包括位阻2,2'-二取代-1,1'-联萘，可以通过各种双炔和芳烃前体的组合来构建。以该反应为关键步骤，实现了台辛C、E和脱氢去氧鬼臼毒素的全合成。此外，还研究了双炔和杂炔的[2+2+2]共环化。因此，镍催化的二炔和3,4-吡啶的[2+2+2]共环反应首次被开发出来，得到了收率较高的异喹啉衍生物。在该反应中，3,4-吡啶前体的吡啶环上的一个供电子取代基被耐受，分别以较高的收率得到了各种取代的异喹啉。另一方面，前驱体吡啶环上的吸电子取代基延缓了[2+2+2]共环化。

This project focused on the development of new reactions of highly strained alkynes such as arynes and heteroarynes using a transition metal catalyst. A novel method for construction of biaryls via palladium-catalyzed [2+2+2] cocyclization of diynes and arynes was developed. By this methodology, various arylnaphthalene derivatives, including a sterically hindered 2,2'-disubstituted-1,1'-binaphthyl, can be constructed by virtue of a variety of combinations of diynes and aryne precursors. Using this reaction as a key step, the total syntheses of taiwanins C, E, and dehydrodesoxypodophyllotoxin were achieved. Furthermore, a [2+2+2] cocyclization of diynes and heteroarynes was also investigated. As the result, a nickel-catalyzed [2+2+2] cocyclization of diynes and 3,4-pyridynes was developed for the first time, affording isoquinoline derivatives in good yields. In this reaction, an electron-donating substituent on the pyridine ring of the 3,4-pyridyne precursor was tolerated, giving various substituted isoquinolines in good yields, respectively. On the other hand, it was found that an electron-withdrawing substituent on the pyridine ring of the precursor retarded the [2+2+2] cocyclization.