在此,我们报告了一种温和的、不含过渡金属的、高度非对映选择性的路易斯酸催化方法,用于通过乙烯基重氮酯和硝酮之间的反应合成基于异恶唑烷的重氮化合物。有趣的是,异恶唑烷产物被认为具有与先前报道的金属催化反应相反的非对映选择性。此外,相同的催化剂可以与烯醇重氮酯一起使用,促进Mukaiyama-Mannich产物的形成。然后这些重氮产物可以进一步官能化以提供苯并[ b ]氮杂卓和吡咯烷酮衍生物。
Cycloadducts of nitrones with isocyanates; 1,2,4- or 1,3,4-oxadiazolidinones?
作者:Anthony M. T. Bell、Jonathan Bridges、Richard Cross、Christopher P. Falshaw、Brian F. Taylor、Giles A. Taylor、Ian C. Whittaker、Michael J. Begley
DOI:10.1039/p19870002593
日期:——
The adducts formed between various aryl-substituted nitrones and aryl isocyanates have been shown, using 15N n.m.r. spectroscopy and X-ray crystallography, to be substituted 1,2,4-oxadiazolidinones and not the previously reported 1,3,4-oxadiazolinones.
使用15 N nmr光谱法和X射线晶体学显示,各种芳基取代的硝酮与芳基异氰酸酯之间形成的加合物被取代的1,2,4-恶二唑烷酮,而不是先前报道的1,3,4-恶二唑啉酮。
Synthesis of 2,3-Disubstituted <i>NH</i> Indoles via Rhodium(III)-Catalyzed C–H Activation of Arylnitrones and Coupling with Diazo Compounds
arylnitrones and diazo compounds by C–H activation/[4 + 1] annulation with a C(N2)–C(acyl) bond cleavage is reported, and 2,3-disubstituted NH indoles are directly synthesized in up to a 94% yield. A variety of functional groups are applicable to this reaction to give the corresponding products with high selectivity. Compared to other previously reported Rh(III)-catalyzed synthesis of homologous series, this method
Rhodium(III)‐Catalyzed Asymmetric Access to Spirocycles through C−H Activation and Axial‐to‐Central Chirality Transfer
作者:Lingheng Kong、Xi Han、Song Liu、Yun Zou、Yu Lan、Xingwei Li
DOI:10.1002/anie.202000174
日期:2020.4.27
Axial-to-central chirality transfer is an important strategy to construct chiral centers, where the axiallychiral reagents are mostly limited to atropomerically stable ones. Reported herein is a RhIII -catalyzed enantioselective spiroannulative synthesis of nitrones. The coupling proceeds via C-Harylation to give an atropomerically metastable biaryl, followed by intramolecular dearomative trapping
Syntheses of 2-Iminoindolin-3-ones and 2-Alknyl-2,3-dihydroquinazolin-4(1<i>H</i>)-ones from 3-Diazoindolin-2-imines
作者:Zhenwei Lin、Jing Qian、Ping Lu、Yanguang Wang
DOI:10.1021/acs.joc.0c01548
日期:2020.9.18
into 2-alknyl-2,3-dihydroquinazolin-4(1H)-ones through a Ag(I)-catalyzed reaction with terminal alkynes. A MeOH-triggered ring expansion mechanism involving cyclic iminium formation and nucleophilic addition is proposed for this novel alkynylation reaction. This two-step procedure provides a general and convenient approach to 2-alknyl-2,3-dihydroquinazolin-4(1H)-ones, which are privileged structures
Synthesis of Benzimidazolones via One-Pot Reaction of Hydroxylamines, Aldehydes, and Trimethylsilyl Cyanide Promoted by Diacetoxyiodobenzene
作者:Huaiyuan Zhang、Danfeng Huang、Ke-Hu Wang、Jun Li、Yingpeng Su、Yulai Hu
DOI:10.1021/acs.joc.6b02781
日期:2017.2.3
A novel and efficient PhI(OAc)2-promoted one-pot reaction of aromatic hydroxylamines, aldehydes, and TMSCN in the presence of BF3·Et2O is described. A wide variety of N-substituted benzimidazolones are obtained with satisfactory yields under mild reaction conditions. The method was proven to be efficient for the synthesis of benzimidazolone derivatives from readily available starting materials.