Palladium Catalyzed Cyclizations of Oxime Esters with 1,2-Disubstituted Alkenes: Synthesis of Dihydropyrroles
作者:Nicholas J. Race、John F. Bower
DOI:10.1021/ol4023112
日期:2013.9.6
Pd-catalyzed cyclizations of oxime esters with 1,2-dialkylated alkenes provide an entry to chiral dihydropyrroles. Substrate and catalyst controlled strategies for selective product formation (vs alternative pyrroles) are outlined.
Microwave-assisted zinc chloride-catalyzed synthesis of substituted pyrroles from homopropargyl azides
作者:Przemysław Wyrębek、Adam Sniady、Nicholas Bewick、Yan Li、Agnieszka Mikus、Kraig A. Wheeler、Roman Dembinski
DOI:10.1016/j.tet.2008.11.094
日期:2009.2
Ligand-free 5-endo-dig cyclization of 1,4- and 1,2,4-substituted but-3-yn-1-yl (homopropargyl) azides in the presence of zinc chloride (usually 20 mol %) in dichloroethane at elevated temperature provides 2,5-di- and 2,3,5-trisubstituted pyrroles in high to moderate yields (91-41%). Both conventional and microwave protocols furnished comparable results. A structure of 2-(4-fluorophenyl)-5-(4-methyl-phenyl)-1H-pyrrole was confirmed by X-ray crystallography. (C) 2008 Elsevier Ltd. All rights reserved.
One-Pot Synthesis of <i>N</i>-Hydroxypyrroles via Soft α-Vinyl Enolization of (<i>E</i>)-β-Chlorovinyl Ketones: A Traceless Arylsulfinate Mediator Strategy
作者:Divya Bhatt、Soyeon Chae、Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.2c00649
日期:2022.4.15
reaction course of β-chlorovinyl ketones with N-hydroxyamine. The soft α-vinyl enolization of (E)-β-chlorovinyl ketones was conducted in the presence of sodium arylsulfinate to give transient alkenyl sulfones that in turn reacted with NH2OH to give novel access to N-hydroxypyrroles. The mechanistic studies revealed the initial formation of oxazine intermediates that rearranged to thermodynamically stable
已经开发了一种无痕芳基亚磺酸盐介质策略来改变 β-氯乙烯基酮与N-羟胺的反应过程。( E )-β-氯乙烯基酮的软 α-乙烯基烯醇化在芳基亚磺酸钠存在下进行,得到瞬态烯基砜,后者又与 NH 2 OH 反应,得到N-羟基吡咯的新途径。机理研究揭示了在微波辅助加热条件下重排成热力学稳定的芳烃产物N-羟基吡咯的恶嗪中间体的初始形成。