Rh(III)-Catalyzed Mild Coupling of Nitrones and Azomethine Imines with Alkylidenecyclopropanes via C–H Activation: Facile Access to Bridged Cycles
作者:Dachang Bai、Teng Xu、Chaorui Ma、Xin Zheng、Bingxian Liu、Fang Xie、Xingwei Li
DOI:10.1021/acscatal.8b00746
日期:2018.5.4
activation of nitrones and azomethine imines in the context of dipolar addition with alkylidenecyclopropanes (ACPs) have been realized. By taking advantage of the ring strain in ACPs, the reaction with aryl nitrones delivered bridged [3.2.1] bicyclicisoxazolidines, and reaction with azomethine imines afforded bridged tricyclic pyrazolones under the same conditions, where both the nitrone and azomethine
cycloadditions between acrolein and various N,N'-cyclic azomethine imines in the presence of L-proline and itsderivatives as organocatalysts were investigated. Reactions that were catalyzed by (S)-indline-2-carboxylic acid (30 mol%) in CHCl 3 /MeOH 97:3 (v/v) showed high exo-selectivities (exo/endo 91:9 ∼ 99:1) and enantioselectivities (75 ∼ 98% ee). In contrast, reactions catalyzed by L-proline (30
A series of thirteen 2-acyl-6,7-dihydro-1H,5H-pyrazolo[1,2-a]pyrazolederivatives were synthesized by using a copper-catalyzed azomethine-imine-alkyne cycloaddition as a key step. These bimane-related fluorescent compounds with λex = 338–400 nm and λem = 522–644 nm exhibit interesting and promising optical properties, including a remarkably large Stokes shift (150–268 nm), positive solvatochromism
以铜催化偶氮甲亚胺-炔烃环加成为关键步骤,合成了13种2-酰基-6,7-二氢-1H , 5H-吡唑并[1,2 - a ]吡唑衍生物。这些具有 λ ex = 338-400 nm 和 λ em = 522-644 nm的双烷相关荧光化合物 表现出有趣且有前途的光学特性,包括非常大的斯托克斯位移 (150-268 nm)、正溶剂化显色性和强烈的发射依赖性在 pH 2-10 范围内对 pH 的强度。苯并三唑啉和N-琥珀酰亚胺酯官能化化合物成功地用作蛋白质标记的荧光探针。