(4 + 3)-Cycloaddition of Donor–Acceptor Cyclopropanes with Thiochalcones: A Diastereoselective Access to Tetrahydrothiepines
作者:André U. Augustin、J. Luca Merz、Peter G. Jones、Grzegorz Mlostoń、Daniel B. Werz
DOI:10.1021/acs.orglett.9b03623
日期:2019.12.6
tetrahydrothiepines using donor-acceptorcyclopropanes. Thiochalcones, functioning as sulfur-containing four-atom building blocks, were reacted in a Lewisacidcatalyzed formal (4 + 3)-cycloaddition reaction with donor-acceptorcyclopropanes as three-atom building blocks. Under mild conditions various tetrahydrothiepines were synthesized in good yields in a stereospecific reaction with high functional group tolerance
Rhodium-Catalyzed Cyclopropanation of Alkenes with Dimethyl Diazomalonate
作者:Francisco González-Bobes、Michaël D. B. Fenster、Susanne Kiau、Laxma Kolla、Sergei Kolotuchin、Maxime Soumeillant
DOI:10.1002/adsc.200800027
日期:2008.4.7
α′-tetramethyl-1,3-benzenedipropanoate] to catalyze the cyclopropanation of a wide range of alkenes with malonate-derived carbenoids under mild reaction conditions is reported in this communication. The experimental protocol is remarkably simple, uses readily accessible and stable dimethyldiazomalonate with very low catalyst loading. More importantly, the alkene is employed as a limiting reagent.
Ring‐Opening 1,3‐Aminochalcogenation of Donor–Acceptor Cyclopropanes: A Three‐Component Approach
作者:André U. Augustin、Peter G. Jones、Daniel B. Werz
DOI:10.1002/chem.201902160
日期:2019.9.6
A 1,3‐aminothiolation was realized by reacting 2‐substituted cyclopropane 1,1‐dicarboxylates with sulfonamides and N‐(arylthio)succinimides. Under Sn(OTf)2 catalysis the transformation proceeded smoothly to the corresponding ring‐opened products bearing the sulfonamide in the 1‐position next to the donor and the arylthio residue in the 3‐position next to the acceptor. The procedure was extended to
Reactivity of donor–acceptor cyclopropanes towards nucleophiles and electrophiles is determined by the specific philicity of the carbon atoms originating from the strong polarization of the central C–C bond. Herein, we report that vitamin B12 catalysis enables the transformation of an initially electrophilic center into a nucleophilic radical that reacts with SOMOphiles. This radical-based strategy
供体 - 受体环丙烷对亲核试剂和亲电试剂的反应性由源自中心 C-C 键的强极化的碳原子的特定亲水性决定。在此,我们报道维生素 B 12催化能够将最初的亲电中心转变为与 SOMophiles 反应的亲核自由基。这种基于自由基的策略逆转了标准的区域选择性,从而补充了经典方法。
Stereospecific Reactions of Donor-Acceptor Cyclopropanes with Thioketones: Access to Highly Substituted Tetrahydrothiophenes
作者:André U. Augustin、Maximilian Sensse、Peter G. Jones、Daniel B. Werz
DOI:10.1002/anie.201708346
日期:2017.11.6
Lewis‐acid‐catalyzed reactions of 2‐substituted cyclopropane 1,1‐dicarboxylates with thioketones are described. Highly substituted tetrahydrothiophenes with two adjacent quaternary carbon atoms were obtained in a stereospecific manner under mild conditions and in high yield when using AlCl3 as Lewis acid. Moreover, an intramolecular approach was successfully implemented to gain access to sulfur‐bridged
描述了路易斯酸催化的2-取代的环丙烷1,1-二羧酸酯与硫酮的反应。当使用AlCl 3作为路易斯酸时,在温和的条件下以立体有择的方式高产率地获得了具有两个相邻的季碳原子的高度取代的四氢噻吩。此外,成功地采用了分子内方法来获得硫桥[ n .2.1]双环系统。在类似条件下,硒酮(较重的类似物)的转化导致形成各种四氢硒代苯。