Intramolecular Stereospecific Pummerer Reactions of Aryl (Substitutedmethyl) Sulfoxides Bearing Electron-withdrawing Groups with Acetic Anhydride
作者:Tatsuo Numata、Osamu Itoh、Toshiaki Yoshimura、Shigeru Oae
DOI:10.1246/bcsj.56.257
日期:1983.1
optically active cyanomethyl aryl sulfoxides with acetic anhydride gave the corresponding α-acetoxy sulfides which were induced with a partial asymmetry nearly 30% at α-carbon, while the 18O-label of the original sulfoxides was retained in more than 85% in the resulting ester, the Pummerer reaction product. Kinetic experiments with cyanomethyl (p-substituted phenyl) sulfoxides and α,α-dideuterated cyanomethyl
旋光性氰甲基芳基亚砜与乙酸酐的普默勒反应得到相应的 α-乙酰氧基硫化物,其在 α-碳上的部分不对称性接近 30%,而原始亚砜的 18O-标记保留在 85% 以上在所得酯中,Pummerer 反应产物。氰甲基(对取代苯基)亚砜和 α,α-二氘代氰甲基对甲苯基亚砜与含有少量乙酸的乙酸酐反应的动力学实验表明,这些速率与哈米特 σ 值和 ρ 值相关得到-0.70,而动力学同位素效应几乎为零,即kH⁄kD=1.01。这些观察结果清楚地表明,重排是分子内的,通过形成非常紧密的离子对进行,决定速率的步骤被认为是初始可逆酰化和去质子化后的 S-O 键断裂。通过Elcb型Pro...