无环的不对称季立体,其由四个碳-碳键,微细地通过利用从手性氨基化锂与三取代(的不对称迈克尔加成反应得到的烯醇化物中间体的面朝选择性烷基化构建ë)-α,β-不饱和酯。目前的面选择性烷基化能够使用不同的卤代烷作为亲电子试剂,以提供具有全碳四元立体中心的各种迈克尔加合物。关于手性助剂的脱保护,我们之前研究中使用的N-碘代琥珀酰亚胺在目前的情况下不起作用;然而,我们发现在 H 2存在下,一氯化吡啶碘O可有效去除氨基上的冰片基和苄基以提供β-氨基酯衍生物。 全尺寸图像
practical method for the synthesis of chiral β2,3-amino esters having various substituents was developed, which is characterized by an asymmetric Michael addition reaction of a chiral lithium amide with trisubstituted (E)-α,β-unsaturated esters. We found that a highly face-selective protonation occurred by the quick addition of water to the enolate intermediate derivedfrom the Michael addition reaction
A facile and convenientsynthesis of trisubstituted (E)-α,β-unsaturated esters was developed by improving our previously established method. The new method circumvented the separation of the intermediates, which have an activating group of the hydroxyl group in β-hydroxy esters, furnishing α,β-unsaturated esters in shorter steps than the previous method: an acetylation of β-hydroxy group and subsequent
organophotoredox-catalyzed stereoselective allylic arylation of MBH acetates with a palette of diaryliodonium triflates (DAIRs) to provide the corresponding trisubstituted alkenes in moderate to good yields. The method could be extended to three-componentcoupling involving 1,4-diazabicyclo[2.2.2]octane bis(sulfur dioxide) adduct (DABSO) as a sulfur dioxide surrogate for the synthesis of biologically relevant