Stereochemical Study on 1,3-Dipolar Cycloaddition Reactions of Heteroaromatic<i>N</i>-Ylides with Symmetrically Substituted cis and trans Olefins
作者:Otohiko Tsuge、Shuji Kanemasa、Shigeori Takenaka
DOI:10.1246/bcsj.58.3137
日期:1985.11
Stereochemistry of the cycloadditions of twenty-four heteroaromatic N-ylides with several symmetrically substituted cis and trans olefins has been investigated. Cyclic and acyclic cis olefins cycloadd to the and form of the ylides in a highly endo-selective manner giving almost quantitative yields of stereospecific endo 3+2 cycloadducts. N-Ylides stabilized with a substituent of carbonyl type react
Free-radical cyclization approach to polyheterocycles containing pyrrole and pyridine rings
作者:Ivan P Mosiagin、Olesya A Tomashenko、Dar’ya V Spiridonova、Mikhail S Novikov、Sergey P Tunik、Alexander F Khlebnikov
DOI:10.3762/bjoc.17.105
日期:——
A wide range of derivatives with new pyrido[2,1-a]pyrrolo[3,4-c]isoquinoline skeleton was synthesized by free-radical intramolecular cyclization of o-bromophenyl-substituted pyrrolylpyridinium salts using the (TMS)3SiH/AIBN system. The cyclization provides generally good yields of pyrido[2,1-a]pyrrolo[3,4-c]isoquinoline hydrobromides having no additional radical-sensitive substituents. The free bases
使用 (TMS) 3 SiH/AIBN通过邻溴苯基取代的吡咯基吡啶鎓盐的自由基分子内环化合成了一系列具有新的吡啶并[2,1- a ]吡咯并[3,4- c ]异喹啉骨架的衍生物系统。环化通常提供没有额外自由基敏感取代基的吡啶并[2,1- a ]吡咯并[3,4- c ]异喹啉氢溴化物的良好产率。游离碱可以通过在室温下碱化以定量收率从合成的氢溴酸盐中获得。分子内芳基化的选择性控制是通过取代卤素来实现的:使用 1-(2-( ortho- bromophenyl)-4-( ortho-碘苯基)吡咯-3-基)溴化吡啶鎓使得有可能获得单环化产物,并且由二溴衍生物获得双环化产物。该程序也适用于获得 3-芳基吡啶并[ 2,1- a ]吡咯并[3,2- c ]异喹啉衍生物,包括无法通过 Pd 催化环化的 2-未取代骨架。
TFA-Mediated DMSO-Participant Sequential Oxidation/1,3-Dipolar Cycloaddition Cascade of Pyridinium Ylides for the Assembly of Indolizines
acid (TFA)-mediated cascadeoxidation/1,3-dipolarcycloaddition reaction of stabilized pyridinium salts with dimethyl sulfoxide (DMSO) has been developed in the presence of K2S2O8 and trimethylethylenediamine (TMEDA). In this transition-metal-free reaction, DMSO acts as a one-carbon source, thus providing a convenient method for the efficient and direct synthesis of various indolizine derivatives.
Stereochemical Study on 1,3-Dipolar Cycloaddition Reactions of Heteroaromatic<i>N</i>-Ylides with Unsymmetrically Substituted Olefinic Dipolarophiles
作者:Otohiko Tsuge、Shuji Kanemasa、Shigeori Takenaka
DOI:10.1246/bcsj.58.3320
日期:1985.11
Regioselectivity and stereoselectivity of the cycloadditions of heteroaromatic N-ylides with unsymmetrically-substituted olefins such as methyl-substituted cis olefins, an acrylate, the related olefins, trans nitro olefins, and other trans olefins have been investigated. These cycloadditions are highly regioselective, while the stereoselectivity depends upon both the electronic and steric nature of
Synthesis of substituted disulfonyl-containing polycyclic azines with the bridgehead nitrogen atom. Effects of the structure of 3-substituted pyridinium ylides on the regioselectivity of their reactions with E-1,2-di(alkylsulfonyl)-1,2-dichloroethenes
作者:N. E. Dontsova、A. M. Shestopalov
DOI:10.1007/s11172-017-1851-3
日期:2017.6
Heating the substituted pyridinium and isoquinolinium salts with E-1,2-di(alkylsulfonyl)-1,2-dichloroethenes in either chloroform or acetone in the presence of three-fold excess of Et3N gave high yields of substituted 1,2-di(alkylsulfonyl)indolizines and 1,2-di(alkylsulfonyl) pyrrolo[2,1-a]isoquinolines, respectively. Effects of the structure of 3-substituted pyridiniumylides on the regioselectivity