Development of New Reactive Intermediates on the Basis of the Reactions of Functionalized Highly Strained Molecules

研究目的：该项目旨在利用应变分子中储存的内部化学能，开发新的反应中间体和新的反应。(1)新的热[3+2]环加成反应。2，2-二烷氧基-1-亚甲基环丙烷与缺电子的烯烃在温和的热条件下反应得到高产率的环戊烷。与羰基化合物的类似反应得到取代的四氢呋喃。反应中间体的反应机理和性质已通过动力学和理论研究得到了阐明。(2)碳化反应。在环丙酮缩醛中加入有机金属化合物，为环丙基金属化合物的化学研究开辟了新的途径，并进一步应用于光学活性化合物的不对称合成。(3)二羰基化合物的合成。在一氧化碳存在下，钯催化的环丙酮缩醛与三氟代芳烃的反应为合成1，4-二羰基化合物提供了新的途径。

Aim of the Research : This program is directed toward the development of new reactive intermediates and new reactions by taking advantage of the internal chemical energy stored in strained molecules.Results : The following three reactions have been developed. (1) New thermal [3+2] cycloaddition. The reaction of 2, 2-dialkoxy-1-methylenecyclopropane with electron-deficient olefins under mild thermal conditions gives cyclopentanes in high yield. A similar reaction with carbonyl compounds affords substituted tetrahydrofurans. The mechanism and the nature of the reactive intermediate have been elucidated by kinetic and theoretical studies. (2) Carbometalation reaction. Addition of organometallics to cyclopropenone acetals provided a new entry to the chemistry of cyclopropyl metal compounds, which was further applied to the asymmetric synthesis of optically active compounds. (3) Synthesis of dicarbonyl compounds. Palladium-catalyzed reaction of cyclopropanone acetals with aryl triflates in the presence of carbon monoxide provided a new entry to the synthesis of 1, 4-dicarbonyl compounds.