The direct organocatalytic desymmetrization of cyclic meso-anhydrides was achieved by alcoholysis with nitroallylic alcohols. The reaction between primary nitroallylic alcohols and cyclic meso-anhydrides catalyzed by cinchonidine derived thiourea organocatalyst II (10 mol %) proceeded smoothly. The corresponding hemiesters were obtained in high chemical yields with high to excellent levels of stereoselectivity
环状内消旋酸酐的直接有机催化去对称化是通过用硝基
烯丙醇进行醇解而实现的。由
辛可尼定衍生的
硫脲有机催化剂II(10 mol%)催化的伯硝基
烯丙醇与环状内消旋酸酐的反应进行得很顺利。相应的半酯以高
化学产率获得,具有高至极好的立体选择性
水平(高达90%的收率和99%的ee)。另一方面,当
氨基
辛可尼定衍
生物(III)在类似反应条件下用作有机催化剂时,观察到对映选择性的逆转。这证明了在环的去对称化中亲核组分的活化的例子。内消旋酸酐。