DEVELOPMENT OF ENVIRONMENTALLY FRIENDLY ACTIVATION PROCESS OF UNREACTIVE OLEFINS AND ITS APPLICATION TO NATURAL PRODUCT SYNTHESIS

最近，作者开发了一种钯催化的环烯基化过程，作为未反应烯烃的一种催化活化方法。已清楚地表明，在一个氧气气氛下，在催化量的醋酸钯的存在下，未反应的烯烃与硅烯醇酸盐进行分子内偶联反应。在这项研究中，作者考察了钯催化的环烯基化反应的全合成。此外，作者还通过钯催化的环烯基化反应合成了双环[3.3.0]辛烷类化合物和双环[4.3.0]壬烷类化合物。(1)全合成：利用钯催化环烷基化反应合成双环[3.2.1]辛烷的独特性质，实现了非对映选择性全合成蜂毒灵。在这个序列中，使用了高度非对映选择性的环氧乙烷来安装C-16官能团。基于钯催化的环烯基化和分子内Diels-Alder反应形成非对映选择性多环环体系相结合的合成策略，应该广泛适用于具有相关结构特征的目标的制备。(2)钯催化环烷基化合成双环[4.3.0]正庚烷、双环[3.3.0]辛烷和相关的苯并衍生物通过钯催化的环烷基化反应可以很容易地合成双环[4.3.0]正庚烷和双环[3.3.0]辛烷。此外，在催化醋酸钯的存在下，通过硅烯醇类化合物与芳环的偶联反应，首次合成了苯并熔融双环[3.3.0]辛烷。值得注意的是，在中性反应条件下，硅烯醇醚的sp2碳与芳香环发生了反应。

Recently, the author has developed a palladium-catalyzed cycloalkenylation process as a catalytic activation method of unreactive olefins. It has become clear that an intramolecular coupling reaction of unreactive olefins with silyl enolates proceeds in the presence of catalytic amount of palladium acetate under one atmosphere of oxygen. In this research, the author has examined total synthesis of aphidicolin by use of palladium-catalyzed cycloalkenylation. In addition, the author has next investigated the construction of blcyclo[3.3.0]octane compounds and bicycio[4.3.0]nonane derivatives by means of the palladium-catalyzed cycloalkenylation.(1)Total Synthesis of AphidicolinA diastereoselective total synthesis of aphidicolin has been achieved by exploiting a unique characteristic of a bicyclo[3.2.1]octane prepared by employing a palladium-catalyzed cycloalkenyaltion process. In this sequence, highly diastereoselective oxirane formation was employed to install C-16 functionality. The strategy used in this aphidicolin synthesis, relying on the combined use of palladium-catalyzed cyclolakenylation and intramolecular Diels-Alder reactions for diastereoselective polycyclic ring system formation, should be broadly applicable to the preparation of targets with related structural features.(2)Simple Construction of Bicyclo[4.3.0]nonane, Blcyclo[3.3.0]octane, and Related Benzo Derivatives by Palladium-Catalyzed CycloalkenylationBicyclo[4.3.0]nonanes (hydrindanes) and blcyclo[3.3.0]octanes (octahydropentarenes) have been easily synthesized by palladium-catalyzed cycloalkenylation. Additionally, benzo-fuzed bicyclo[3.3.0]octanes have been prepared for the first time through coupling between silyl enolates and aromatic rings in the presence of catalytic palladium acetate. It is notable that reaction between sp2 carbons of silyl enol ether and an aromatic ring was observed under neutral reaction conditions.