Synthetic Reactions by Using Bimetallic Complexes

在催化合成反应中，单金属配合物得到了广泛的应用，而双金属配合物在实际合成中很少使用。精确设计双金属配合物是实现多金属中心协同反应的独特化学转化的重要途径。本研究制备了homo和hetero双金属配合物，并对其实现有机转化的催化活性进行了研究。1)制备了磷桥接铑钨羰基配合物，在W部分作为CO供体和/或Lewis酸度的辅助下，期望Rh(I)的催化活性。Rh-W双金属配合物在CO分压小于0.04 atm的条件下对单取代烯烃的氢甲酰化反应具有较高的催化活性，官能团选择性较强。制备了氧桥或硫桥双金属，并用x射线晶体学分析研究了它们的结构。氧桥配合物在烯烃加氢反应中表现出独特的性质；也就是说，外层的烯烃可以顺利氢化，而配体烯烃（环二烯）则不能。2)氮化嘧啶和乙烯基叠氮化物很容易生成性质尚未完全明确的乙烯基亚硝基金属配合物，特别是用铑（II）双金属配合物和铜（II）配合物处理时。通过芳香C-H胺化反应和活性亚甲基化合物与乙烯基亚硝基金属配合物的加成反应，催化制备了吲哚和吡咯。3)在环丙醇氧化生成β-酮自由基的研究过程中，发现银(I)配合物具有较高的活性。通过加入适量的再氧化试剂完成催化过程，并应用于分子内扩环。β-酮自由基的催化生成非常强大，可以构建融合环，因此以该催化为关键步骤实现了(-)-sordarin的合成。少

In catalytic synthetic reactions, monometallic complexes have been widely used, while bimetallic complexes rarely used in practical synthesis. Precise design of bimetallic complexes is expected to realize unique chemical transformations, in which multi metal centers take part in the reactions collaboratively. In this research, homo and hetero bimetallic complexes were prepared and their catalytic activities were studied to realize organic transformations.1)Phosphido-bridged rhodium-tungsten carbonyl complexes were prepared, expecting catalytic activity of Rh(I) with the assistance by the W part as a CO donor and/or Lewis acidity. A Rh-W bimetallic complex exhibited high catalytic activity in the hydroformylation of monosubstituted alkenes even under less than 0.04 atm partial pressure of CO, with a wide functional group selectivity. A oxygen- or sulfur-bridged bimetallic were prepared and their structures were studied by X-ray crystallographic analysis. The oxygen-bridged complex exhib … More ited a unique character in the hydrogenation of alkenes; that is, outer alkenes are smoothly hydrogenated, while the ligand alkene (cyclooctadiene) is not.2)Vinyl nitrene-metal complexes, the property of which is not fully clarified yet, was found to be easily generated from azirines and vinyl azides, particularly by the treatment with rhodium(II) bimetallic complexes and copper(II) complexes. Indoles and pyrroles were prepared catalytically by aromatic C-H amination and addition reaction of active methylene compounds to the vinyl nitrene-metal complexes.3)During the course of the study on the oxidative generation of β-keto radicals from cyclopropanols, silver(I) complexes are found to show high activity. Catalytic process was accomplished by adding adequate reoxidation reagent and applied for the intramolecular ring expansion. The catalytic generation of β-keto radicals was so powerful to construct fused rings that synthesis of (-)-sordarin was achieved by using the catalysis as the key step. Less