Development of Novel Synthetic Methods Based on Selective Oxidation of Organometallics

通过与过渡金属的单电子氧化还原，有机金属化合物的单电子氧化或还原允许基于金属上的电子状态的改变的新颖反应行为，这被认为提供新颖的合成反应。如果采用金属间化合物的过渡金属化，则基于引入金属的特性的反应性有望拓宽通过金属有机中间体的合成方法的范围。具有单电子氧化能力的氧钒化合物用于此目的，在本研究项目中。研究了金属有机化合物的氧化转化，为选择性碳-碳键的形成提供了一种通用的方法。1）通过烷基锂处理烯基铝得到的有机铝酸盐配合物与氧钒氧化剂进行氧化偶联，选择性地得到相应的烯炔。该反应适用于多种有机铝化合物; 2）以芳基铝代替烯基铝进行类似的氧化偶联反应; 3）用钒氧化合物直接氧化芳基二烷基铝，引入烷基，得到烷基取代的芳烃.钒氧化合物的空间体积和氧化还原电位反映在氧化偶联上。一锅转化是可能的，无需分离中间体络合物，并被认为是合成潜力。有机金属化合物和氧钒化合物之间的氧化还原相互作用可能允许这些转化。该耦合被认为是主族有机金属的形式还原消除，这是不太容易通过常规方法。

One-electron oxidation or reduction of organometallics by one-electron redox with transition metals permits a novel reaction behavior based on the change of the electronic state on metals, which is considered to provide novel synthetic reactions. If transmetallation is taken place instead, the reactivities based on the characteristics of the introduced metals are expected to widen the scope of stnthetic methods via organometallic intermediates. Oxovanadium compounds with one-electron oxidation capability are employed for this purpose in this research project. The oxidative transformations of organometallics have been investigated to provide versatile methods for selective carbon-carbon bond formation.1) Organoaluminum ate complexes obtained by treatment of alkenylaluminums with alkyllithiums underwent oxidative coupling with oxovanadium oxidant to afford the corresponding enynes selectively. This reaction was found to be applied to a variety of organoaluminum compounds.2) The similar oxidative coupling reaction proceeded well starting from arylaluminums in stead of alkenyl ones.3) The direct oxidation of aryldialkylaluminums with oxovanadium compounds led to the introduction of an alkyl group to give the alkyl-substituted arenes. The steric bulkiness and redox potentials of oxovanadium compounds reflected on the oxidative coupling. The one-pot transformations are possible without isolation of the intermediate complexes and considered to be of synthetically potetial. The redox interaction between organometallics and oxovanadium compounds is likely to permit these transformations. The coupling is recognized to be formal reductive elimination of main-group organometallics, which has been less accessible by conventional methods.