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Development of Novel Oxidative Transformation Based on Heterometallic Electron Transfer

基于异金属电子转移的新型氧化转化的发展

基本信息

批准号：
11450341
负责人：
HIRAO Toshikazu
金额：
$ 9.02万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

One-electron oxidation of main-group 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 takes place instead, the reactivities based on the characteristics of the introduced metals are expected to widen the scope of synthetic 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) Oxovanadium (V) compounds like VO (OEt) Cl_2 serve as useful oxidants for organozinc compounds, providing the corresponding cross-coupling products derived from two ligands of organozinc compounds. In particular, triorganozincates undergo selective cross-coupling smoothly by the action of oxovanadium (V).2) VO (OEt) Cl_2 induces oxidative ligand coupling of aryltrimethylzincates, prepared from bromoarenes and Me_4ZnLi_2, giving the corresponding methylarenes.3) Oxovanadium (V) compounds induce nucleophilic α, β-vicinal dialkylation of cyclic α, β-enones with dialkylzinc reagents. Alkylzinc enolates, generated from cyclic enones and lithium trialkylzincates, are oxidized by VO (OEt) Cl_2, giving 2, 3-dialkylcycloalkanones. The one-pot transformation is possible without isolation of the intermediate complexes and considered to be of synthetically potetial.The redox interaction between main-group organometallics and oxovanadium compounds is demonstrated to permit these transformations. The coupling is recognized to be formal reductive elimination of the organometallics, which has been less accessible by conventional methods.

主族有机金属的单电子氧化与过渡金属的单电子氧化还原使得基于金属电子态变化的新反应行为得以实现，这被认为是一种新的合成反应。如果发生金属转化，则基于引入金属特性的反应性有望通过有机金属中间体扩大合成方法的范围。本研究采用具有单电子氧化能力的氧化钒化合物。有机金属化合物的氧化转化已经被研究，为选择性碳-碳键的形成提供了多种方法。1) VO (OEt) Cl_2等氧化钒(V)化合物是有机锌化合物的有用氧化剂，提供了有机锌化合物的两种配体的交偶联产物。特别是，三有机锌酸盐在氧化钒(V)的作用下可以顺利地进行选择性交叉偶联。2)VO (OEt) Cl_2诱导溴芳烃和Me_4ZnLi_2合成芳基三甲基锌酸盐的氧化配体偶联，得到相应的甲基芳烃。3)氧化钒(V)化合物诱导亲核α、β-邻环α、β-烯酮与二烷基锌试剂的二烷基化反应。由环烯酮和三烷基锌酸锂合成烷基锌烯醇酯，经VO (OEt) Cl_2氧化得到2,3 -二烷基环烷酮。在不分离中间配合物的情况下，一锅转化是可能的，并且被认为是具有合成潜力的。主族有机金属和氧化钒化合物之间的氧化还原相互作用被证明允许这些转化。这种耦合被认为是有机金属的形式还原消除，这是传统方法难以实现的。