P(NMe<sub>2</sub>)<sub>3</sub>-Mediated Umpolung Spirocyclopropanation Reaction of <i>p</i>-Quinone Methides: Diastereoselective Synthesis of Spirocyclopropane-Cyclohexadienones
作者:Yu-Hua Deng、Wen-Dao Chu、Yun-Han Shang、Ke-Yin Yu、Zhi-Long Jia、Chun-An Fan
DOI:10.1021/acs.orglett.0c02998
日期:2020.11.6
substitution offers a new method for effective access to a series of highly functionalized spirocyclohexadienonyl cyclopropanes having two vicinal quaternary carbons in ≤98% yield and >20:1 dr. Significantly, cyclic and acyclic topological structures of α-keto carbonyls as 1,1-dipole one-carbon synthons have a distinct influence on the stereochemistry of products, showing a reversal of diastereoselectivity
描述了空前的对醌甲基化物和α-酮羰基的空螺环丙烷化反应。我们基于1,6-共轭加成和分子内亲核取代的umpolung策略提供了一种新方法,可有效获得一系列具有两个邻位季碳的高功能化螺环己二壬基环丙烷,产率≤98%,且dr> 20:1。值得注意的是,α-酮羰基作为1,1-偶极一碳合成子的环状和无环拓扑结构对产物的立体化学有明显的影响,在这种P(NMe 2)3介导的螺螺环丙烷化中显示出非对映选择性的逆转。