Remarkable effect of copper chloride on diiodination of zirconacyclopentadienes
摘要:
Treatment of zirconacyclopentadienes with two equiv of iodine in THF in the presence of 1.0 equiv of CuCl gave diiododienes in good to high yields without formation of monoiododienes. This is in sharp contrast to the case without CuCl which afforded monoiododienes as major products. For zirconacyclopentenes. CuCl was also effective but the use of ICl was more practical. When zirconacyclopentenes were treated with 2 equiv of ICl, only diiodination products were formed. Preparation of silacyclopentadienes or spiro compounds using the diidodienes was demonstrated. (C) 1997 Elsevier Science Ltd.
Synthesis of 1,3-Difluoroaromatics in One Pot by Addition of Difluorocarbene from Sodium Chlorodifluoroacetate to 1,2-Substituted Cyclobutenes
作者:Heather M. Morrison、James E. Rainbolt、Scott B. Lewis
DOI:10.1021/ol020158j
日期:2002.10.1
[formula: see text] The synthesis of 1,3-difluoro-2,4-diphenylbenzene has been accomplished in one step from 1,2-diphenylcyclobutene using the environmentally benign difluorocarbene precursor sodium chlorodifluoroacetate. In addition, the preparation of the previously unknown compound 1,3-difluoro-2,4-di-n-propylbenzene has been accomplished in one step from 1,2-di-n-propylcyclobutene using Seyferth's
Selective cyclometalation of disubstituted acetylenes and ethylene with diethylmagnesium and ethylmagnesium halides in the presence of zirconium complexes
作者:R. M. Sultanov、V. V. Vasil’ev、U. M. Dzhemilev
DOI:10.1134/s1070428010030097
日期:2010.3
Catalytic cyclometalation of disubstituted acetylenes and ethylene with ethylmagnesium halides EtMgHlg (Hlg = Cl, Br) and diethylmagnesium Et2Mg in the presence of Cp2ZrCl2 gave tetrasubstituted magnesacyclopenta-2,4-dienes and disubstituted magnesacyclopent-2-enes. A probable scheme of formation of cyclic unsaturated organomagnesium compounds was proposed, according to which the reactive intermediates
Copper-catalyzed one-pot N-alkenylation and N-alkylation of amides: an efficient synthesis of substituted 2,3-dihydropyrroles
作者:Xiaobo Zhou、Huimin Zhang、Jiwei Yuan、Lugen Mai、Yanzhong Li
DOI:10.1016/j.tetlet.2007.07.221
日期:2007.10
A novel copper-catalyzed synthesis of substituted 2,3-dihydropyrroles via one-pot N-alkenylation and N-alkylation of amides with 1,4-diiodobut-1-ene derivatives has been developed. The reactions proceed in good to high yields using CuI as the catalyst, K2CO3 as the base, and rac-trans-N,N′-dimethylcyclohexane-1,2-diamine as the ligand.
已经开发出一种新的铜催化的酰胺经1,4-二碘丁-1-烯衍生物的酰胺的一锅N-烯基化和N-烷基化合成的取代2,3-二氢吡咯。反应进行以良好至高产率使用的CuI作为催化剂,K 2 CO 3作为碱,和外消旋-反式- Ñ,Ñ 'N'-二甲基环己烷-1,2-二胺作为配体。
Highly chemoselective reactions of zirconacyclopentenes for selective functionalization
Alcoholysis of zirconacyclopentenes proceeds at the alkyl carbon on Zr with high chemoselectivity in sharp contrast to monoiodination of Zirconacyclopentenes with iodine; alcoholysis followed by iodination of Zirconacyclopentenes produces stereodefined trisubstituted alkenyl iodides in high yields with high isomeric purities.
Copper-catalyzed synthesis of five-membered heterocycles via double C–N bond formation: an efficient synthesis of pyrroles, dihydropyrroles, and carbazoles
作者:Ende Li、Xiaobing Xu、Hongfeng Li、Huimin Zhang、Xiaolei Xu、Xiyuan Yuan、Yanzhong Li
DOI:10.1016/j.tet.2009.08.075
日期:2009.10
An efficient copper-catalyzed double C-N bond forming reaction using diiodides and nitrogen-centered nucleophiles including amides and carbamates is reported. The reactions proceed to afford di- or tri-substituted N-acylpyrroles, dihydropyrroles, and carbazoles in good to excellent yields when different such as 1,4-diiodo-1,3-butadienes, 1,4-dihalobut-1-enes, and 2,2'-diiodobiphenyls were employed, respectively. It is crucial to use CuI as the catalyst with the assistance of proper base and diamine ligand. (C) 2009 Elsevier Ltd. All rights reserved.