924882-07-5Relevant academic research and scientific papers
Functionalized Cyclopropanes as Versatile Intermediates for the Diversity-Oriented Synthesis of γ-Lactones, γ-Lactams and δ-Lactams
Maximiano, Adrielle P.,Ramos, Giovana S.,Marques, Marcelo V.,Sá, Marcus M.
, (2021/03/18)
A two-step procedure for the preparation of cyclopropanecarboxaldehyde-1,1-diester from a γ,δ-epoxyester and its synthetic versatility are described herein. The epoxide ring-opening/cyclopropanation process occurs in the presence of Mg(ClO 4) 2under heating, resulting in cyclopropanemethanol-1,1-diester in 65% yield. A mild TEMPO-mediated oxidation of this substrate readily generated the corresponding aldehyde in 75% yield, which was applied in the one-pot synthesis of four cyclopropylidene-γ-lactams and three δ-lactams. In addition, vinylcyclopropanes were obtained through the Wittig reaction of the aldehyde with phosphonium salts and used as precursors for tetrahydrofurans.
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.
Lewis Acid-Catalyzed [3+3] Annulation of Donor-Acceptor Cyclopropanes and Indonyl Alcohols: One Step Synthesis of Substituted Carbazoles with Promising Photophysical Properties
Varshnaya, Rohit Kumar,Banerjee, Prabal
, p. 1614 - 1623 (2019/02/07)
A highly efficient protocol to access carbazole from donor-acceptor cyclopropane and indonyl alcohol via [3+3] annulation in the presence of a Lewis acid has been demonstrated. This method facilitates the post functionalization of the substituted carbazol
[3+3] Annulation via Ring Opening/Cyclization of Donor–Acceptor Cyclopropanes with (Un)symmetrical Ureas: A Quick Access to Highly Functionalized Tetrahydropyrimidinones
Taily, Irshad Maajid,Saha, Debarshi,Banerjee, Prabal
, p. 7804 - 7813 (2019/12/27)
A mild and straight-forward access to pharmacologically privileged tetrahydropyrimidinones exploiting readily available Donor–Acceptor cyclopropanes (DACs) is reported. This methodology involves the Lewis acid catalyzed synthesis of uriedo-malonates from (un)symmetrical ureas and DACs followed by I2-base mediated cyclization to their corresponding tetrahydropyrimidinones. The cyclization protocol involves nucleophilic attack of the nitrogen of urea on the newly generated electrophilic acceptor end of DAC. The post functionalization offered potential biologically active molecules.
Lewis Acid Catalyzed Formal [3+2] Cycloaddition of Donor-Acceptor Cyclopropanes and 1-Azadienes: Synthesis of Imine Functionalized Cyclopentanes and Pyrrolidine Derivatives
Verma, Kamal,Banerjee, Prabal
supporting information, p. 3848 - 3854 (2017/11/15)
Lewis acid catalyzed formal [3+2] cycloadditions of 1-azadienes with donor acceptor cyclopropanes to synthesize varieties of imine functionalized cyclopentanes and pyrrolidine derivatives in moderate to high yield have been developed. Moreover, pharmaceut
Construction of Isoxazolidines through Formal [3+2] Cycloaddition Reactions of in situ Generated Nitrosocarbonyls with Donor–Acceptor Cyclopropanes: Synthesis of α-Amino γ-Butyrolactones
Varshnaya, Rohit Kumar,Banerjee, Prabal
, p. 4059 - 4066 (2016/08/24)
A straightforward approach for the synthesis of isoxazolidines through MgI2-catalyzed [3+2] cycloaddition reactions of donor–acceptor cyclopropanes with in situ generated nitrosocarbonyls from hydroxycarbamates is described. This method facilit
Lewis Acid-Catalyzed [3+2] Cycloaddition of Donor-Acceptor Cyclopropanes and Enamines: Enantioselective Synthesis of Nitrogen-Functionalized Cyclopentane Derivatives
Verma, Kamal,Banerjee, Prabal
supporting information, p. 2053 - 2058 (2016/07/16)
A straightforward and efficient method for the synthesis of nitrogen-functionalized cyclopentane derivatives via [3+2] cycloaddition of enamines with donor-acceptor cyclopropanes in the presence of catalytic amounts of various Lewis acids at room temperat
Ring-Opening of Vinylcyclopropane-1,1-dicarboxylates by Boronic Acids under Ligandless Palladium Catalysis in Neat Water
Yin, JieXiang,Hyland, Christopher J. T.
, p. 6529 - 6536 (2015/10/06)
We report a highly efficient ring-opening reaction of vinylcyclopropanes by boronic acids in water, using palladium nanoparticles formed from Pd(OAc)2 under ligandless conditions. Unsubstituted vinylcyclopropanes provide linear addition products with high selectivity, while a switch in regioselectivity to branched products is observed for aryl-substituted vinylcyclopropanes.
A dimethylsulfonium methylide mediated highly regioselective olefination of conjugated polyolefin 1,1-dioates to conjugated polyene-2-yl-malonates and their applications in Diels-Alder reactions
Singh, Rekha,Ghosh, Sunil K.
supporting information; experimental part, p. 2284 - 2292 (2010/06/16)
The reactions between dimethylsulfonium methylide and 1,3-diene- or 1,3,5-triene-1,1-dioates under specific conditions enable the highly regioselective tandem ylide addition-eliminative olefination to provide 1,3-butadien-2-yl- or 1,3,5-hexatriene-2-yl-malonates. Alkylation at malonate methine carbon of 1,3-butadien-2-ylmalonates with a suitable alkyl halide having in-built functionalities for a dienophile generation led to quick assembly of precursors for type 2 intramolecular Diels-Alder reaction. Syntheses of functionalized bicyclo[n.3.1] alkenes (n=5 or 6) with the double bond at the bridgehead position have been achieved via the IMDA. An asymmetric version of this reaction has been developed using a MacMillan's imidazolidinone catalyst, which provided a bicyclo[5.3.1] alkene with very high enantioselectivity. In situ methylation at malonate methine carbon of 1,3,5-hexatriene-2-yl-malonates followed by intermolecular Diels-Alder reaction with N-methylmaleimide provided the cycloadduct with complete regiocontrol and high diastereoselectivity.
