Iron-Catalyzed Cyclization of Nitrones with Geminal-Substituted Vinyl Acetates: A Direct [4 + 2] Assembly Strategy Leading to 2,4-Disubstituted Quinolines
作者:Mingbing Zhong、Song Sun、Jiang Cheng、Ying Shao
DOI:10.1021/acs.joc.6b01910
日期:2016.11.18
An iron-catalyzed intermolecular [4 + 2] cyclization of arylnitrones with geminal-substituted vinyl acetates was developed for the synthesis of 2,4-disubstituted quinolines in moderate to good yields with good functional group compatibilities. Preliminary mechanistic studies suggest a plausible iron-catalyzed C–H activation process under external-oxidant-free conditions.
Addition of Silyl Ketene Acetals to Nitrones Catalyzed by Lanthanide Triflates
作者:Changtao Qian、Longcheng Wang
DOI:10.1016/s0040-4020(00)00636-0
日期:2000.9
α-Aryl-N-phenyl nitrones reacted with silyl ketene acetals mediated by lanthanum trifloromethanesulfonate (triflate) to afford the addition product in excellent yield under mild conditions. α-Aryl-N-tert-butyl nitrone reacted with ethyl trimethylsilylacetate to yield the unexpected α,β-unsaturated ester in a 100% E-form. A possible mechanism for the process is discussed.
Synthesis of Exclusively 4-Substituted β-Lactams through the Kinugasa Reaction Utilizing Calcium Carbide
作者:Abolfazl Hosseini、Peter R. Schreiner
DOI:10.1021/acs.orglett.9b01192
日期:2019.5.17
A new Kinugasa reaction protocol has been elaborated for the one-pot synthesis of 4-substituted β-lactams utilizing calcium carbide and nitrone derivatives. Calcium carbide is thereby activated by TBAF·3H2O in the presence of CuCl/NMI. The ease of synthesis and use of inexpensive chemicals provides rapid access of practical quantities of β-lactams exclusively substituted at position 4.
An Unprecedented Formal [5 + 2] Cycloaddition of Nitrones with <i>o</i>-Carboryne via Tandem [3 + 2] Cycloaddition/Oxygen Migration/Aromatization Sequence
作者:Da Zhao、Jiji Zhang、Zuowei Xie
DOI:10.1021/jacs.5b09074
日期:2015.11.4
molecules. Cycloaddition reaction has created new opportunities to access heterocycles of great complexity due to its advantage of multiple bond formation in a single step. Here, we describe an unprecedented formal [5 + 2] cycloaddition of nitrone with o-carboryne to afford carborane-fused seven-membered heterocycles. Experimental and theoretical data suggest that a sequence of [3 + 2] cycloaddition, N-O
Synthesis and Fungicidal Activity of Substituted 3-(1,2-Oxazolidin-3-yl)pyridines
作者:A. V. Kuzenkov、V. V. Zakharychev、A. N. Volkova
DOI:10.1134/s1070428018050147
日期:2018.5
Substituted3-(1,2-oxazolidin-3-yl)pyridines were synthesized by 1,3-dipolar cycloaddition of ethyl acrylate, styrene, and their derivatives to N-(pyridin-3-ylmethylidene)-N-phenylaminoxide. The obtained compounds exhibit a fungicidal activity.