Facile and Stereoselective Access to Nonracemic Tricyclic Cyclobutanes by Asymmetric Intramolecular Michael−Aldol Reaction: Thermodynamic Equilibrium and Activation by Iodonium Ion
作者:Kiyosei Takasu、Megumi Ueno、Masataka Ihara
DOI:10.1021/jo010207q
日期:2001.6.1
Intramolecular Michael-aldol reactions of (-)-phenylmenthyl enoates tethered to cycloalkanone affords tricyclic cyclobutanes with high degrees of diastereochemical control. Kinetic and thermodynamic studies revealed that the Michael-aldol reaction is reversible under conditions in which trimethylsilyl iodide is used in the presence of hexamethyldisilazane at ambient temperature. Different levels of
连接到环烷酮的(-)-苯基薄荷基烯酸酯的分子内迈克尔-醛醇缩合反应提供了高度非对映化学控制的三环环丁烷。动力学和热力学研究表明,在六甲基二硅氮烷存在下于环境温度下使用三甲基甲硅烷基碘化物的条件下,Michael-aldol反应是可逆的。当该环化过程在动力学和热力学条件下进行时,观察到不同水平的非对映选择性。最后,已经注意到添加碘鎓供体对反应速率的影响。