A New Approach to the Construction of Carbon Framework Using Metallacumulene Derivatives

作为一种独特的合成试剂，1，2-丙二烯(烯)作为一种独特的合成试剂，存在着许多累积的双键基团的反应。其中，有效地利用了累积双键的特性，这是简单的双键或三键所不能达到的。在本研究中，我将亚乙烯和烯丙基化合物分别识别为1，2-丙二烯和1，2，3-丁三烯的金属类似物，并注意了金属异丁烯中碳-碳双键的反应活性。我计划寻找最大限度地利用它们的特性的合成反应，并且将金属堆积烯作为两个或三个碳单元。我首先研究了从已知的相对富电子的金属--Rh和Ir合成偏亚甲基络合物。根据传统的方法，我试图通过异构化和氢转移从低价的Rh络合物和末端炔烃中制备它们。我失败了，但通过炔基的环加成反应得到了多环化合物。因此，我重点研究了低价后过渡金属催化的烯烃和烯烃的环加成反应，特别是利用手性金属催化的不对称反应。例如，过渡金属催化的[2+2+2]环加成反应是构建六元环体系的成熟方案。我开发了一种新型的不对称[2+2+2]环加成反应，用于合成四元碳立体中心。各种1，4-二烯-YNE的分子内反应在手性铑催化剂上进行，得到了具有应变双环[2.2.1]庚烯骨架或双环-1，3-二烯的三环化合物，这取决于1，4-二烯部分上的取代基。

There are many reactions of 1, 2-propadienes(allenes), which have cumulated double bond moieties, as unique synthetic reagents. Among them, the features of the cumulated double bond are effectively utilized, that cannot be achieved by simple double or triple bond. In this research, I recognize vinylidene and allenylidene complexes as metal analogue of 1, 2-propadienes and 1, 2, 3-butatriene, respectively, and pay attention to the reactivity of carbon-carbon double bond in metallacumulenes. I plan to search for synthetic reactions that make the best use of their characteristics, and that use metallacumulenes as two or three carbon unit.I first examined the synthesis of vinylidene complexes from rhodium and iridium ones, which are known to be relatively electron-rich metals. According to the conventional methods, I tried to prepare them from low valent rhodium complexes and terminal alkynes via isomerization along with a hydrogen transfer. I failed but obtained multicyclic compounds by cycloaddition of alkyne moieties. Thus, I focused on the development of low valent late transition metal catalyzed-cycloaddition of alkynes and alkenes, especially enantioselective reaction using chiral metal catalysts.For example, transition metal-catalyzed[2+2+2] cycloaddition is a well-established protocol for the construction of six-membered ring systems. I developed a new type of enantioselective[2+2+2] cycloaddition for the synthesis of quaternary carbon stereocenters. The intramolecular reaction of various 1, 4-diene-ynes proceeded using a chiral rhodium catalyst and tricyclic compounds possessing a strained bicyclo[2.2.1] heptene skeleton or bicyclic cyclo-1, 3-dienes were obtained, depending on the substituent on the 1, 4-diene moiety.