Gold(I)‐Catalyzed Highly Diastereo‐ and Enantioselective Cyclization–[4+3] Annulation Cascades between 2‐(1‐Alkynyl)‐2‐alken‐1‐ones and Anthranils
作者:Rahul Dadabhau Kardile、Tzu‐Hsuan Chao、Mu‐Jeng Cheng、Rai‐Shung Liu
DOI:10.1002/anie.202001854
日期:2020.6.22
This work reports gold‐catalyzed [4+3]‐annulations of 2‐(1‐alkynyl)‐2‐alken‐1‐ones with anthranils to yield epoxybenzoazepine products with excellent exo ‐diastereoselectivity (dr>25:1). The utility of this new gold catalysis is manifested by applicable substrates over a broad scope. More importantly, the enantioselective versions of these [4+3]‐cycloadditions have been developed satisfactorily with
Gold(I)-Catalyzed Reactions between 2-(1-Alkynyl)-2-alken-1-ones and Vinyldiazo Ketones for Divergent Synthesis of Nonsymmetric Heteroaryl-Substituted Triarylmethanes: <i>N-</i> versus <i>C</i>-Attack Paths
作者:Rahul Dadabhau Kardile、Rai-Shung Liu
DOI:10.1021/acs.orglett.0c02765
日期:2020.11.6
Gold-catalyzed synthesis of nonsymmetrical heteroaryl-substitutedtriarylmethanes using 2-(1-alkynyl)-2-alken-1-ones and vinyldiazo ketones is described. In this catalytic sequence, vinyldiazo ketones attack gold-containing 3-furylbenzyl cations to form the observed C(1)-addition products. We also note that vinyldiazo ketones can be thermally cyclized to yield pyrazole derivatives, which can react
Chemoselective CC Bond Cleavage of Epoxide Motifs: Gold(I)-Catalyzed Diastereoselective [4+3] Cycloadditions of 1-(1-Alkynyl)oxiranyl Ketones and Nitrones
作者:Tao Wang、Junliang Zhang
DOI:10.1002/chem.201002395
日期:2011.1.3
Cutting carbon! A novel facile strategy for the CCbondcleavage of oxiranylketones has been developed. Carbophilic gold(I) activation of the alkyne side chain mediates a heterocyclization and subsequent CCbondcleavage (see scheme).
An organocatalyticasymmetricformal [3 + 2] cycloaddition of enynones with N-hydroxylamines has been described. A newly designed multifunctional organocatalyst was found to be highly effective, and the method allowed the synthesis of a variety of 2,3-dihydroisoxazoles in good yields with excellent enantioselectivity.
addition of dianionic cyano-aci-nitroacetate to α-chloro-α,β-unsaturated ketones followed by intramolecular nucleophilic substitution of the nitronate ion intermediate. In this process, the dianionic reagent serves as the safe synthetic equivalent of the explosive nitroacetonitrile. The 3-cyano group is sufficiently reactive toward ethanolysis and 1,3-dipolar cycloaddition with an azide to afford ethyl
一系列的5酰化3- cyanoisoxazoles被有效通过迈克尔加成的双阴离子合成氰基ACI -nitroacetate到α氯α,β不饱和酮,接着氮酸盐离子中间体的分子内亲核取代。在此过程中,双阴离子试剂可作为爆炸性乙腈的安全合成当量。3-氰基对叠氮化物的乙醇分解和1,3-偶极环加成反应性足够,分别得到乙酯和四唑。还构建了5-酰基和4-芳基之间的吡啶环。这导致了异恶唑并[5,4- c ]喹啉衍生物的形成。