[3 + 2]-Annulation of <i>gem</i>-Difluoroalkenes and Pyridinium Ylides: Access to Functionalized 2-Fluoroindolizines
作者:Jun-Qi Zhang、Dandan Hu、Jinyu Song、Hongjun Ren
DOI:10.1021/acs.joc.0c03041
日期:2021.3.19
A [3 + 2]-annulation of gem-difluoroalkenes and pyridinium ylides was developed employing ambient air as the sole oxidant in an open-vessel manner, affording a series of multifunctionalized 2-fluoroindolizines in moderate to good yields. In this reaction, gem-difluoroalkene acts as a C2 synthon and entirely avoids the competitive addition–elimination process, which provides facile access to 2-fluoroindolizines
Synthesis and photophysical insights of new fused N-heterocyclic derivatives with isoquinoline skeleton
作者:Carmen Gherasim、Anton Airinei、Radu Tigoianu、Anda M. Craciun、Ramona Danac、Alina Nicolescu、Dragos Lucian Isac、Ionel I. Mangalagiu
DOI:10.1016/j.molliq.2020.113196
日期:2020.7
Six new fused isoquinoline based compounds (compounds 5a–c with pyrrolo[2,1-a] isoquinoline structure and compounds 6a–c with imidazo[2,1-a]isoquinoline skeleton) have been synthesized using the [3 + 2] cycloaddition of the several in situ generated cycloimmonium ylides to ethyl propiolate or ethyl cyanoformate. All the synthesized compounds have been investigated in solution by UV–VIS absorption,
使用[3 + 2]环加成法合成了六种新的基于异喹啉的稠合化合物(具有吡咯并[2,1- a ]异喹啉结构的化合物5a–c和具有咪唑并[2,1- a ]异喹啉骨架的化合物6a–c)。在几个原位中生成的环亚铵盐生成丙酸乙酯或氰基甲酸乙酯。所有合成的化合物都通过UV-VIS吸收,稳定和时间分辨的荧光方法在溶液中进行了研究。已经证明了取代基对光谱特性的影响。这些衍生物显示出在360至420 nm之间的强烈发射。吡咯并异喹啉衍生物在二甲基亚砜(DMSO)中的发射量子产率(Φ= 0.54-0.64)显着高于咪唑并喹啉(0.03-0.16)。异喹啉衍生物的荧光衰减遵循双指数定律。观察到这些异喹啉衍生物对氢氧化钠的明显反应。
Preparation of tetrahydroindolizines from pyridinium and isoquinolinium ylides
作者:Alan R. Katritzky、Nicholas E. Grzeskowiak、Julio Alvarez-Builla
DOI:10.1039/p19810001180
日期:——
Carbonyl- and nitrile-stabilised pyridinium and cyclic azonium methylides condense with chalcones to form tetrahydroindolizines and analogous fused pyrrolidines. The stereochemistry is illuminated by 13C and 1H n.m.r. spectroscopy. Several incorrect literature structures are rectified.
羰基和腈稳定的吡啶鎓和环状的偶氮鎓甲基化物与查耳酮缩合,形成四氢吲哚并二苯并类似的稠合吡咯烷。立体化学由13 C和1 H nmr光谱照亮。纠正了一些错误的文献结构。
Diversified Transformations of Tetrahydroindolizines to Construct Chiral 3-Arylindolizines and Dicarbofunctionalized 1,5-Diketones
four-stereogenic centered tetrahydroindolizine intermediates could be efficiently transferred into axially chirality in 3-arylindolizines and vicinal pyridyl and aryl substituted 1,5-diketones. In addition, densely functionalized cyclopropanes and bridgedcyclic compound were also discovered depended on the nature of the pyridinium ylides. Mechanism studies were involved to explain the stereochemistry during the
Construction of C(sp<sup>2</sup>)–X (X = Br, Cl) Bonds through a Copper-Catalyzed Atom-Transfer Radical Process: Application for the 1,4-Difunctionalization of Isoquinolinium Salts
作者:Qiu Sun、Yuan-Yuan Zhang、Jing Sun、Ying Han、Xiaodong Jia、Chao-Guo Yan
DOI:10.1021/acs.orglett.7b03751
日期:2018.2.16
A highly efficient Cu-catalyzed 1,4-difunctionalization of isoquinolinium salts was developed with ether and X– (X = Br, Cl) as the halogen source under mild conditions. This transformation involves the combination of oxidative coupling and copper-catalyzed halogen atom-transfer radicalprocesses. This method not only provides an efficient way to prepare various substituted azaarenes but also achieves