Organic Synthesis Using Electroauxiliaries

我们提出了一个新的概念，电辅助作为一个有用的工具，在电子转移驱动的反应。电助剂激活反应物分子，以促进电子转移过程，并控制由此产生的反应物质的化学过程，以选择性地产生所需的产物。我们发现硅、锡和硫是杂原子化合物氧化的优良电助剂。发现电辅助的概念对杂原子化合物的氧化碳-碳键形成是有用的。以锡和硫为电助剂，发展了几种电氧化碳-碳键形成反应。这个概念也被发现是有机化合物的位点选择性转化，因为我们可以很容易地区分分子不同位点的电助剂，利用它们的氧化还原电位的差异。我们还研究了电助剂的作用机理。在硅和锡的情况下，碳-金属sigma轨道与杂原子的非成键轨道的相互作用加速了电子转移，从而提高了HOMO能级。然而，在硫的情况下，没有观察到这种相互作用，发现电子转移主要来自硫原子。

We propose a new concept of electroauxiliary as a useful tool in electron transfer-driven reactions. Electroauxiliaries activate reactant molecules to facilitate the electron transfer process and also control the chemical process of thus generated reactive species to give desired products selectively.We have found that silicon, tin, and sulfur serve as excellent electroauxiliaries for the oxidation of heteroatom compounds. The concept of electroauxiliary was found to be useful for oxidative carbon-carbon bond formation of heteroatom compounds. Several electrooxidative carbon-carbon bond formation reactions using tin and sulfur as electroauxiliaries have been developed.This concept was also found to be site-selective transformation of organic compounds because we can easily distinguish between electroauxiliaries at different sites of molecule using the difference of their redox potential.We also investigated the mechanism of the action of electroauxiliaries. In the case of silicon and tin, the electron transfer is accelerated by the interaction of the carbon-metal sigma orbital with the nonbonding porbital of the heteroatom which raises the HOMO level. In the case of sulfur, however, such interaction was not observed and the electron transfer was found to take place mainly from the sulfur atom.