Fine tuning the outcome of 1,3-dipolar cycloaddition reactions of benzimidazolium ylides to activated alkynes
作者:Emilian Georgescu、Alina Nicolescu、Florentina Georgescu、Florina Teodorescu、Sergiu Shova、Adriana T. Marinoiu、Florea Dumitrascu、Calin Deleanu
DOI:10.1016/j.tet.2016.03.086
日期:2016.5
1,3-Dipolarcycloaddition reactions of benzimidazolium ylides, generated from 3-phenacylbenzimidazolium bromides, to non-symmetrical activated dipolarophiles in various reaction conditions led to complex mixtures of pyrrolo[1,2-a]benzimidazole and pyrrolo[1,2-a]quinoxaline derivatives. In order to explain all experimental results, the influence of reaction conditions on the reaction products was investigated
在各种反应条件下,由3-苯甲基苯并咪唑鎓溴化物生成的苯并咪唑鎓烷基化物的1,3-偶极环加成反应与非对称活化偶极亲和剂导致吡咯并[1,2- a ]苯并咪唑和吡咯并[1,2- a的复杂混合物]喹喔啉衍生物。为了解释所有实验结果,研究了反应条件对反应产物的影响。首次出现4-羟基-4,5-二氢吡咯并[1,2 - a ]喹喔啉衍生物6,吡咯并[1,2- a ]喹喔啉季盐8以及4-甲氧基-4,5-二氢吡咯并酮[1,2- a ]喹喔啉9被分离出来,被充分表征,并提出它们的相互转化,以及提出的反应机理。
Selective C–H trifluoromethylation of benzimidazoles through photoredox catalysis
作者:Guo-Lin Gao、Chao Yang、Wujiong Xia
DOI:10.1039/c6cc08975e
日期:——
This protocol presented a new strategy for visible-light induced C-H trifluoromethyltion at C4 of benzimidazoles using Togini's reagent in the presense of fac-Ir(ppy)3. It's Highlighted by its operational simplicity, mild...
benzimidazolium salts have been synthesized and fully characterized by multinuclear NMR spectroscopy. The benzimidazolium salts occur as intermediates in various 1,3-dipolarcycloadditions and they are also useful as starting materials in such cycloadditions. Graphic abstract
Herein we report a novel Cu-catalyzed regioselective C2–H alkylation of benzimidazoles with aromatic alkenes. The reaction features exclusive regioselectivity and broad substrate scope in the intermolecular alkylation of benzimidazoles with terminal and internal aromatic alkenes, constituting a modular access toward benzimidazole-containing 1,1-di(hetero)aryl alkanes. The intramolecular C2–H alkylation
Palladium-Catalyzed Dehydrogenative Cross-Couplings of Benzazoles with Azoles
作者:Wei Han、Peter Mayer、Armin R. Ofial
DOI:10.1002/anie.201006208
日期:2011.2.25
Different enough: Palladium‐catalyzed cross‐couplings of benzazoles with imidazoles, oxazoles, and thiazoles furnish unsymmetrical 2,2′‐bisheteroaryls in high yield (see scheme). These oxidative CC bond formations use the selective cleavage of the CH bond at C2 in the two coupling partners and are robust enough to be conducted under normal air atmosphere.