The Unexpected Role of Se
<sup>VI</sup>
Species in Epoxidations with Benzeneseleninic Acid and Hydrogen Peroxide
作者:Kai N. Sands、Emerita Mendoza Rengifo、Graham N. George、Ingrid J. Pickering、Benjamin S. Gelfand、Thomas G. Back
DOI:10.1002/anie.201913566
日期:2020.3.9
acid in the presence of hydrogen peroxide. The selenonic acid is inert towards cyclooctene on its own; however, rapid epoxidation occurs when hydrogen peroxide is added. This shows that the selenonic acid must first be activated through further oxidation, presumably to the heretofore unknown benzeneperoxyselenonic acid. The latter is the principal oxidant in this epoxidation.
苯过氧硒酸已被提出作为广泛使用的烯烃与苯硒酸和过氧化氢环氧化的关键中间体。然而,它与环辛烯反应缓慢,而是在溶液中迅速分解为混合的硒化硒酸硒酸盐,该盐通过X射线吸收和77 Se NMR光谱以及单晶X射线衍射鉴定。该方法包括通过释放氧气的亚硒酸消除过氧硒酸和其他氧化还原步骤。该盐在固态下相对稳定,但是在过氧化氢的存在下产生相应的亚硒酸。亚硒酸本身对环辛烯呈惰性;然而,当添加过氧化氢时,会发生快速的环氧化。这表明亚硒酸必须首先通过进一步的氧化活化,大概是迄今未知的苯过氧硒酸。后者是该环氧化反应中的主要氧化剂。