Stereochemical and conformational consequences of the oxidation of 1,4-thiazane-3,5-dicarboxylates
作者:Craig A. Hutton、Rania Jaber、Michelle Otaegui、Jennifer J. Turner、Peter Turner、Jonathan M. White、George B. Bacskay
DOI:10.1039/b202231a
日期:2002.5.22
The stereoselectivity of the oxidation of 1,4-thiazane-3,5-dicarboxylate derivatives to the corresponding sulfoxides and sulfones was found to be dependent on the type of oxidant used and the conformational preference of the substrate. Direct oxidants, such as sodium periodate, peroxides and peracids, preferentially react with the axial sulfur lone-pair, providing the axial S-oxide. Oxidation with bromine–water yielded the epimeric equatorial S-oxide, presumably as a result of initial attack of the axial sulfur lone pair providing the axial bromosulfonium ion, with subsequent displacement of bromide by water leading to the equatorial S-oxide.
研究发现,1,4-噻嗪-3,5-二甲酸酯衍生物氧化成相应的硫醚和砜的立体选择性取决于所用氧化剂的类型和底物的构象偏好。高碘酸钠、过氧化物和过酸等直接氧化剂会优先与轴向的硫孤对发生反应,生成轴向的 S-氧化物。与溴水发生氧化反应后会产生二价的赤道 S-氧化物,这可能是由于轴硫孤对受到最初的攻击,产生了轴溴锍离子,随后溴被水置换,产生了赤道 S-氧化物。