Development of Five-membered Ring Forming Reactions by Control of Electronic States of Biradical

着眼于控制双基种电子结构的可能性，研究者开展了[3+2]环加成反应形成五元环的研究。从而实现了对三甲基乙烷（TMM）和乙烯基自由基（VC）的电子控制，生成了新的偶极三碳四电子反应物质，并发展了这些物质与双电子受体的反应，实现了新的五元环化合物的合成。主要成果总结如下：(1)取代TMM和VC的反应性控制。利用高应变单环、环丙烯和亚甲基环丙烷，对TMM和VC生成反应进行了动力学研究，并将研究结果应用于环戊烷和鹿蹄草碱化合物的合成。(2)富勒烯功能化。已发现TMM和VC与富勒烯发生反应，并将结果应用于水溶性富勒烯的各种性质的研究，包括生物活性、单分子膜的形成和放射性衍生物的合成。(3)自由基反应的超声控制。研究了超声辐照对自由基反应的控制能力。

Focusing on the possibility of controlling the electronic structures of biradical species, the investigator carried out a research on the [3+2] cycloaddition reaction to form five-membered rings. As the result, electronic control of the trimethylenemethane (TMM) and vinyl radical (VC) species has been achieved to generate new dipolar three-carbon, four-electron reactive species, and the reactions of these species with two-electron acceptors have been developed to realize new synthesis of five-membered ring compounds. The major achievements are summarized as follows.(1) Reactivity control of substituted TMM and VC species. By the use of the highly strained monocyclic rings, cyclopropene and methylenecyclopropane, the investigator performed kinetic studies on the TMM and VC formation reactions, and applied the results to the synthesis of cyclopentane and pyrollidine compounds. (2) Fullerene functionalization. TMM and VC have been found to react with fullerenes, and the results were applied for the studies various properties of water-soluble fullerenes including biological activities, monolayr formation, and synthesis of radioactive derivatives. (3) Ultrasound control of radical reactions. The ability of ultrasound irradiation for the control of radical reactions have been studied.