A Synthetic Route to Chiral Tetrahydropyrroloindoles via Ring Opening of Activated Aziridines with 2-Bromoindoles Followed by Copper-Catalyzed C–N Cyclization
作者:Masthanvali Sayyad、Abhijit Mal、Imtiyaz Ahmad Wani、Manas K. Ghorai
DOI:10.1021/acs.joc.6b01049
日期:2016.8.5
A new syntheticroute to nonracemic tetrahydropyrrolo[2,3-b]indoles has been developed via SN2-type ringopening of enantiopure N-activated aziridines with 2-bromoindoles followed by copper-catalyzed C–Ncyclization. A series of N-activated aziridines and 2-bromoindole derivatives with different substitution patterns were studied to afford the corresponding tetrahydropyrrolo[2,3-b]indoles in good yields
通过用2-溴吲哚将对映纯N活化的氮丙啶的S N 2型开环,然后进行铜催化的CN环化,已开发出一种新的合成非外消旋四氢吡咯并[2,3- b ]吲哚的途径。研究了一系列具有不同取代模式的N活化氮丙啶和2-溴吲哚衍生物,从而以良好的收率和优异的ee(高达99%)提供了相应的四氢吡咯并[2,3- b ]吲哚。高度取代的四氢吡咯并[2,3- b ]吲哚由对映体纯的反式-二取代的氮丙啶合成为单个立体异构体(de,ee> 99%)。
Syntheses of Chiral β- and γ-Amino Ethers, Morpholines, and Their Homologues via Nucleophilic Ring-Opening of Chiral Activated Aziridines and Azetidines
作者:Manas K. Ghorai、Dipti Shukla、Aditya Bhattacharyya
DOI:10.1021/jo300002u
日期:2012.4.20
Lewis acid catalyzed quaternary ammonium salt mediated highly regioselective ring-opening of chiral activated aziridines and azetidines with alcohols to nonracemic β- and γ-amino ethers has been developed. The reaction mainly proceeds via an SN2 pathway, and the partial racemization of the starting substrate was effectively controlled by using quaternary ammonium salts. β- and γ-amino ethers are obtained
已经开发了路易斯酸催化的季铵盐介导的手性活化氮丙啶和氮杂环丁烷与醇的非区域性β-和γ-氨基醚的高度区域选择性开环。该反应主要通过S N 2途径进行,并且通过使用季铵盐有效地控制了起始底物的部分消旋。以高对映体和非对映体特异性(ee最高> 99%,最高99%)获得β-和γ-氨基醚。当将卤代醇用作亲核试剂时,该方法进一步扩展为合成具有高对映体特异性的吗啉及其同系物(ee高达90%)。
Readily available nitrene precursors increase the scope of Evans' asymmetric aziridination of olefins
作者:Mikael J. Södergren、Diego A. Alonso、Pher G. Andersson
DOI:10.1016/s0957-4166(97)00496-5
日期:1997.11
The performance of the copper-catalyzed asymmetric aziridination of olefins is highly dependent on the properties of the nitrene precursor. Our preliminary results show significant improvements of both enantioselectivity and chemical yields when [N-(4-nitrobenzenesulfonyl)imino] phenyliodinane 1b (p-NO2C6H4SO2N=IPh) is employed instead of the commonly used p-tolyl analog 1a (PhI=NTs). This paper reports the comparison of some nitrene precursors for the copper-catalyzed asymmetric aziridination of olefins, utilizing the olefin as the limiting component and 1.5 equivalents of the nitrene precursor. The aziridine derivatives of several olefins were obtained in moderate to excellent yields and with enantioselectivity up to 95% ee. (C) 1997 Elsevier Science Ltd.
Stereoselective Lewis Acid Mediated (3+2) Cycloadditions of<i>N</i>-H- and<i>N</i>-Sulfonylaziridines with Heterocumulenes
作者:Robert A. Craig、Nicholas R. O'Connor、Alexander F. G. Goldberg、Brian M. Stoltz
DOI:10.1002/chem.201303699
日期:2014.4.14
Alkyl and arylisothiocyanates and carbodiimides are effective substrates in (3+2) cycloadditions with N‐sulfonyl‐2‐substituted aziridines and 2‐phenylaziridine for the synthesis of iminothiazolidines and iminoimidazolidines. Additionally, the stereoselective (3+2) cycloaddition of N‐H‐ and N‐sulfonylaziridines with isothiocyanates can be accomplished, allowing for the synthesis of highly enantioenriched
Enantioselective Syntheses of Morpholines and Their Homologues via S<sub>N</sub>2-Type Ring Opening of Aziridines and Azetidines with Haloalcohols
作者:Manas K. Ghorai、Dipti Shukla、Kalpataru Das
DOI:10.1021/jo901297d
日期:2009.9.18
yield and enantioselectivity of a variety of substituted nonracemic morpholines and their homologues is described. The reaction proceeds via an SN2-type ring opening of activated aziridines and azetidines by suitable halogenated alcohols in the presence of Lewis acid followed by base-mediated intramolecular ring closure of the resulting haloalkoxy amine.