3092-20-4Relevant academic research and scientific papers
A practical and reusable catalyst for the synthesis of donor-acceptor cyclopropane
Zhang, Yanqun,Jin, Manyu,Wu, Cunqi,Zhao, Yongxia,Zhou, Hua,Xu, Jingwei
, p. 5 - 9 (2018)
Herein, a convenient, recyclable and inexpensive Cu-based catalytic system is developed for the synthesis of donor-acceptor (D-A) cyclopropane via the cycloaddition of styrene derivatives with diethyl bromomalonate. A core-shell catalyst of Fe3
Copper(II) Halide Catalyzed Cyclopropanation of Olefins Involving Dehydrobromination of Bromomalonic Ester by Amine
Kawabata, Nariyoshi,Yanao, Shinji,Yoshida, Jun-ichi
, p. 2687 - 2688 (1982)
The reaction of olefins with bromomalonic ester and 1,8-diazabicycloundec-7-ene (DBU) proceeded in the presence of a catalytic amount of copper(II) halide to give 1,1-bis(alkoxycarbonyl)cyclopropane derivatives.DBU was converted into DBU-hydrobromi
Synthesis of Thio-/Selenopyrrolines via SnCl4-Catalyzed (3+2)-Cycloadditions of Donor-Acceptor Cyclopropanes with Thio-/Selenocyanates
Ali, Shamsad,Goswami, Avijit,Kalaramna, Pratibha,Singh, Prasoon Raj
supporting information, p. 4683 - 4689 (2021/09/10)
A straightforward protocol has been developed to access thio-/selenopyrrolines through a (3+2)-cycloaddition of aryl thio-/selenocyanates with donor-acceptor cyclopropanes (DACs) in the presence of SnCl4 as a Lewis acid catalyst. Further, good chemoselectivity was observed when DACs were treated with 3-cyano phenyl thiocyanate. These results suggest that thiocyanate is more reactive than nitrile moiety in such (3+2)-cycloaddition reactions.
Accessing dihydro-1,2-oxazine via cloke-wilson-type annulation of cyclopropyl carbonyls: application toward the diastereoselective synthesis of pyrrolo[1,2- b][1,2]oxazine
Banerjee, Prabal,Kumar, Pankaj,Kumar, Rakesh
supporting information, p. 6535 - 6550 (2020/06/09)
A convenient additive-free synthesis of dihydro-4H-1,2-oxazines via a Cloke-Wilson-type ring expansion of the aryl-substituted cyclopropane carbaldehydes with the hydroxylamine salt is introduced. Comparatively less active cyclopropyl ketones also follow a similar protocol if supplemented by catalytic p-toluene sulfonic acid monohydrate. The transformation is performed in an open-to-air flask as it shows negligible sensitivity toward air/moisture. Dihydro-4H-1,2-oxazines when subjected to cycloaddition with the cyclopropane diester afford a trouble-free formulation of the valued hexahydro-2H-pyrrolo[1,2-b][1,2]oxazine derivatives. A cascade one-pot variant of this two-step strategy offers a comparable overall yield of the final product.
(3 + 2)-Cycloaddition of Donor-Acceptor Cyclopropanes with Selenocyanate: Synthesis of Dihydroselenophenes and Selenophenes
Jacob, Anu,Jones, Peter G.,Werz, Daniel B.
supporting information, (2020/11/13)
We present a Lewis-acid-catalyzed (3 + 2)-cycloaddition of donor-acceptor cyclopropanes and selenocyanate (as its tetramethylammonium salt) for the synthesis of dihydroselenophenes. The transformation proceeded with moderate to excellent yields and showed a high functional group tolerance. Further oxidation using DDQ delivered selenophenes.
Stereospecific copper(II)-catalyzed tandem ring opening/oxidative alkylation of donor-acceptor cyclopropanes with hydrazones: Synthesis of tetrahydropyridazines
Mishra, Manmath,De, Pinaki Bhusan,Pradhan, Sourav,Punniyamurthy, Tharmalingam
, p. 10901 - 10910 (2019/09/13)
Aerobic copper(II)-catalyzed tandem ring opening and oxidative C-H alkylation of donor-acceptor cyclopropanes with bisaryl hydrazones is accomplished to produce tetrahydropyridazines, in which copper(II) plays dual role as a Lewis acid as well as redox catalyst. The reaction is stereospecific, and optically active cyclopropanes can be reacted with high optical purities (89-98% enantiomeric excess). The substrate scope, functional group tolerance, dual role of the copper(II) catalyst, and the use of air as an oxidant are the important practical features. A product bearing a 3-bromoaryl group can be subjected to Pd-catalyzed Suzuki coupling with boronic acid in high yield.
Lewis Acid Catalyzed Annulation of Cyclopropane Carbaldehydes and Aryl Hydrazines: Construction of Tetrahydropyridazines and Application Toward a One-Pot Synthesis of Hexahydropyrrolo[1,2- b]pyridazines
Dey, Raghunath,Kumar, Pankaj,Banerjee, Prabal
, p. 5438 - 5449 (2018/05/28)
In this report, a facile synthesis of tetrahydropyridazines via a Lewis acid catalyzed annulation reaction of cyclopropane carbaldehydes and aryl hydrazines has been demonstrated. Moreover, the generated tetrahydropyridazine further participated in a cycloaddition reaction with donor-acceptor cyclopropanes to furnish hexahydropyrrolo[1,2-b]pyridazines. We also performed these two steps in one pot in a consecutive manner. In addition, a monodecarboxylation reaction of hexahydropyrrolo[1,2-b]pyridazine was achieved with a good yield.
Nucleophilic Ring Opening of Donor-Acceptor Cyclopropanes Catalyzed by a Br?nsted Acid in Hexafluoroisopropanol
Richmond, Edward,Vukovi?, Vuk D.,Moran, Joseph
supporting information, p. 574 - 577 (2018/02/10)
A general, Br?nsted acid catalyzed method for the room temperature, nucleophilic ring opening of donor-acceptor cyclopropanes in fluorinated alcohol solvent, HFIP, is described. Salient features of this method include an expanded cyclopropane scope, including those bearing single keto-acceptor groups and those bearing electron-deficient aryl groups. Notably, the catalytic system proved amenable to a wide range of nucleophiles including arenes, indoles, azides, diketones, and alcohols.
Synthesis of Indenopyridine Derivatives via MgI2-Promoted [2+4] Cycloaddition Reaction of In-situ Generated 2-Styrylmalonate from Donor-Acceptor Cyclopropanes and Chalconimines
Verma, Kamal,Banerjee, Prabal
supporting information, p. 3687 - 3692 (2018/10/15)
An unexpected MgI2-promoted [2+4] cycloaddition reaction of in-situ generated 2-styrylmalonate from donor-acceptor cyclopropanes with chalconimines to synthesize highly substituted indenopyridine derivatives under the mild reaction conditions h
Redox-Neutral Photocatalytic Cyclopropanation via Radical/Polar Crossover
Phelan, James P.,Lang, Simon B.,Compton, Jordan S.,Kelly, Christopher B.,Dykstra, Ryan,Gutierrez, Osvaldo,Molander, Gary A.
supporting information, p. 8037 - 8047 (2018/07/03)
A benchtop stable, bifunctional reagent for the redox-neutral cyclopropanation of olefins has been developed. Triethylammonium bis(catecholato)iodomethylsilicate can be readily prepared on multigram scale. Using this reagent in combination with an organic photocatalyst and visible light, cyclopropanation of an array of olefins, including trifluoromethyl- and pinacolatoboryl-substituted alkenes, can be accomplished in a matter of hours. The reaction is highly tolerant of traditionally reactive functional groups (carboxylic acids, basic heterocycles, alkyl halides, etc.) and permits the chemoselective cyclopropanation of polyolefinated compounds. Mechanistic interrogation revealed that the reaction proceeds via a rapid anionic 3-exo-tet ring closure, a pathway consistent with experimental and computational data.
