18511-60-9Relevant articles and documents
The copper-catalyzed ring-opening reactions of cyclopropanes by N-fluorobenzenesulfonimide toward N-allylsulfonamides
Zhou, Aijun,Shao, Ying,Chen, Fan,Qian, Peng-Cheng,Cheng, Jiang
supporting information, (2022/01/03)
In this paper, we reported a copper-catalyzed ring-opening reaction of arylcyclopropanes by N-fluorobenzenesulfonimide, leading to N-allylsulfonamides in moderate to good yields. This procedure tolerated bromo, fluoro, trifluoromethyl, phenyl and alkyl groups in the phenyl, proceeding with a sequential ring-opening of arylcyclopropanes, and copper-mediated β-H elimination of alkyl radical.
Silylium-Ion-Promoted Ring-Opening Hydrosilylation and Disilylation of Unactivated Cyclopropanes
Bonetti, Vittorio,Klare, Hendrik F. T.,Oestreich, Martin,Roy, Avijit,Wang, Guoqiang,Wu, Qian
supporting information, (2020/02/04)
A silylium-ion-promoted ring-opening hydrosilylation of unactivated cyclopropanes is reported. The reaction is facilitated by the γ-silicon effect, and the regioselectivity is influenced by various stabilizing effects on the carbenium-ion intermediates, including the β-silicon effect. The experimental observations are in accord with the computed reaction mechanism. The work also showcases the ability of silylium ions to isomerize cyclopropyl to allyl groups, and the resulting α-olefins engage in a silylium-ion-mediated disilylation with hexamethyldisilane.
Intermolecular Electrophilic Bromoesterification and Bromoetherification of Unactivated Cyclopropanes
Leung, Vincent Ming-Yau,Gieuw, Matthew H.,Ke, Zhihai,Yeung, Ying-Yeung
supporting information, p. 2039 - 2044 (2020/04/20)
1,3-difunctionalization of cyclopropane is an useful organic transformation. The corresponding 1,3-difunctionalized products are synthetic synthons and building blocks in many organic syntheses. Many existing ring-opening difunctionalization methodologies rely primarily on the use of donor?acceptor cyclopropanes, while the difunctionalization of unactivated cyclopropanes is less exploited. In this research, 1,3-bromoesterification and 1,3-bromoetherification of unactivated cyclopropanes were successfully achieved using N-bromosuccinimide as the brominating agent with high yields and regioselectivity. (Figure presented.).
Photoredox catalysis with aryl sulfonium salts enables site-selective late-stage fluorination
Li, Jiakun,Chen, Junting,Sang, Ruocheng,Ham, Won-Seok,Plutschack, Matthew B.,Berger, Florian,Chabbra, Sonia,Schnegg, Alexander,Genicot, Christophe,Ritter, Tobias
, p. 56 - 62 (2019/11/28)
Photoredox catalysis, especially in combination with transition metal catalysis, can produce redox states of transition metal catalysts to facilitate challenging bond formations that are not readily accessible in conventional redox catalysis. For arene functionalization, metallophotoredox catalysis has successfully made use of the same leaving groups as those valuable in conventional cross-coupling catalysis, such as bromide. Yet the redox potentials of common photoredox catalysts are not sufficient to reduce most aryl bromides, so synthetically useful aryl radicals are often not directly available. Therefore, the development of a distinct leaving group more appropriately matched in redox potential could enable new reactivity manifolds for metallophotoredox catalysis, especially if arylcopper(iii) complexes are accessible, from which the most challenging bond-forming reactions can occur. Here we show the conceptual advantages of aryl thianthrenium salts for metallophotoredox catalysis, and their utility in site-selective late-stage aromatic fluorination.
Lewis Base-Promoted Ring-Opening 1,3-Dioxygenation of Unactivated Cyclopropanes Using a Hypervalent Iodine Reagent
Gieuw, Matthew H.,Ke, Zhihai,Yeung, Ying-Yeung
supporting information, p. 3782 - 3786 (2018/03/13)
A facile and effective system has been developed for the regio- and chemoselective ring-opening/electrophilic functionalization of cyclopropanes through C?C bond activation by [bis(trifluoroacetoxy)iodo]benzene with the aid of the Lewis basic promoter p-toluenesulfonamide. The p-toluenesulfonamide-promoted system works well for a wide range of cyclopropanes, resulting in the formation of 1,3-diol products in good yields and regioselectivity.
Aminofluorination of Cyclopropanes: A Multifold Approach through a Common, Catalytically Generated Intermediate
Pitts, Cody Ross,Ling, Bill,Snyder, Joshua A.,Bragg, Arthur E.,Lectka, Thomas
supporting information, p. 6598 - 6609 (2016/06/09)
We have discovered a highly regioselective aminofluorination of cyclopropanes. Remarkably, four unique sets of conditions-two photochemical, two purely chemical-generated the same aminofluorinated adducts in good to excellent yields. The multiple, diverse ways in which the reaction could be initiated provided valuable clues that led to the proposal of a "unifying" chain propagation mechanism beyond initiation, tied by a common intermediate. In all, the proposed mechanism herein is substantiated by product distribution studies, kinetic analyses, LFERs, Rehm-Weller estimations of ΔGET, competition experiments, KIEs, fluorescence data, and DFT calculations. From a more physical standpoint, transient-absorption experiments have allowed direct spectroscopic observation of radical ion intermediates (previously only postulated or probed indirectly in photochemical fluorination systems) and, consequently, have provided kinetic support for chain propagation. Lastly, calculations suggest that solvent may play an important role in the cyclopropane ring-opening step.
Cyclopropanation of styrenes and stilbenes using lithiomethyl trimethylammonium triflate as methylene donor
Sarria Toro, Juan M.,Den Hartog, Tim,Chen, Peter
supporting information, p. 10608 - 10610 (2014/10/15)
Lithiomethyl trimethylammonium triflate, prepared from tetramethylammonium triflate, cyclopropanates several styrenes and stilbenes with electron-donating and selected electron-withdrawing substituents efficiently. Kinetic data support a stepwise nucleophilic addition-ring closure mechanism for this methylenation. This journal is the Partner Organisations 2014.
