5354-13-2Relevant academic research and scientific papers
Electricity Driven 1,3-Oxohydroxylation of Donor-Acceptor Cyclopropanes: a Mild and Straightforward Access to β-Hydroxy Ketones
Saha, Debarshi,Maajid Taily, Irshad,Banerjee, Prabal
, p. 5053 - 5057 (2021/09/30)
An unprecedented external oxidant-free electrochemical protocol for 1, 3-oxohydroxylation of donor-acceptor cyclopropane is disclosed. The strategy encompasses the activation of the labile π-electron cloud of the aryl ring to cleave the strained Csp3?Csp3 bond of cyclopropane to afford the β-hydroxy ketones via insertion of molecular oxygen. More significantly, based on the detailed mechanistic investigations and cyclic voltammetry experiments, a plausible mechanism is proposed.
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+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 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.
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
Substituent and Lewis Acid Promoted Dual Behavior of Epoxides towards [3+2]-Annulation Reactions with Donor-Acceptor Cyclopropanes: Synthesis of Substituted Cyclopentane and Tetrahydrofuran
Pandey, Ashok Kumar,Varshnaya, Rohit Kumar,Banerjee, Prabal
, p. 1647 - 1656 (2017/04/06)
Substituent and Lewis acid promoted generation of functionalized enolates from epoxides is developed. Divergent attack of the enolate on donor-acceptor cyclopropanes, i.e. C-attack or O-attack depending upon substituents present in both reacting partners, produced different products. C-attack gave functionalized cyclopentane derivatives, whereas O-attack furnished tetrahydrofuran derivatives through [3+2]-annulation reactions. Moreover, to increase the utility of our method, synthesized diastereomeric cyclopentane derivatives were converted into synthetically useful cyclopentene and cyclopentanone analogs.
Lewis Acid Catalyzed Diastereoselective Cycloaddition Reactions of Donor-Acceptor Cyclopropanes and Vinyl Azides: Synthesis of Functionalized Azidocyclopentane and Tetrahydropyridine Derivatives
Dey, Raghunath,Banerjee, Prabal
supporting information, p. 304 - 307 (2017/04/21)
Lewis acid catalyzed [3 + 2]-cycloaddition reaction of donor-acceptor cyclopropanes with vinyl azides has been developed to obtain diastereomerically enriched azidocyclopentane derivatives. In addition, thermal chemoselective ring expansion of azidocyclopentanes to tetrahydropyridine derivatives and further diastereospecific reduction to a substituted piperidine derivative, with an excellent yield, was also achieved.
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
Ring Expansion of Donor-Acceptor Cyclopropane via Substituent Controlled Selective N-Transfer of Oxaziridine: Synthetic and Mechanistic Insights
Ghosh, Asit,Mandal, Subhajit,Chattaraj, Pratim Kumar,Banerjee, Prabal
supporting information, p. 4940 - 4943 (2016/10/18)
A distinctive N-substituent controlled electrophilic N-transfer of oxaziridines with donor-acceptor cyclopropanes in the presence of MgI2 is reported. Contrary to earlier reports, the oxaziridine having bulkier N-substituents can also give N-transferred product instead of the O-transferred one. Interestingly, the oxaziridines having α-H containing N-substituents lead to the pyrrolidine derivatives through [3 + 2] cycloaddition. A mechanistic reasoning for this divergent reactivity is depicted by density functional theory calculations and validated through energy decomposition analysis.
