Accessing Dihydro-1,2-oxazine via Cloke–Wilson-Type Annulation of Cyclopropyl Carbonyls: Application toward the Diastereoselective Synthesis of Pyrrolo[1,2-<i>b</i>][1,2]oxazine
作者:Pankaj Kumar、Rakesh Kumar、Prabal Banerjee
DOI:10.1021/acs.joc.0c00531
日期:2020.5.15
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
Synthesis of Indenopyridine Derivatives <i>via</i>
MgI<sub>2</sub>
-Promoted [2+4] Cycloaddition Reaction of <i>In-situ</i>
Generated 2-Styrylmalonate from Donor-Acceptor Cyclopropanes and Chalconimines
作者:Kamal Verma、Prabal Banerjee
DOI:10.1002/adsc.201800598
日期:2018.10.4
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 have been developed. Additionally, these derivatives were utilized for the synthesis of highly substituted 9‐membered lactam by oxidative C=C bond cleavage and
Synthesis of Thio‐/Selenopyrrolines
<i>via</i>
SnCl
<sub>4</sub>
‐Catalyzed (3+2)‐Cycloadditions of Donor‐Acceptor Cyclopropanes with Thio‐/Selenocyanates
A highly efficient protocol for the synthesis of thio-/selenopyrrolines has been developed via a SnCl4-catalyzed (3+2)-cycloaddition of aryl thio-/selenocyanates with donor-acceptor cyclopropanes (DACs). The protocol rendered a variety of thio-/selenopyrrolines in good to excellent yields.
Construction of Isoxazolidines through Formal [3+2] Cycloaddition Reactions of in situ Generated Nitrosocarbonyls with Donor-Acceptor Cyclopropanes: Synthesis of α-Amino γ-Butyrolactones
作者:Rohit Kumar Varshnaya、Prabal Banerjee
DOI:10.1002/ejoc.201600582
日期:2016.8
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 facilitates one-pot synthesis of α-amino-γ-butyrolactone by deprotection, reductive cleavage of N–O bond, and successive lactonization.
Lewis acid triggered <i>N</i>-alkylation of sulfoximines through nucleophilic ring-opening of donor–acceptor cyclopropanes: synthesis of γ-sulfoximino malonic diesters
作者:Satish G. More、Gurunath Suryavanshi
DOI:10.1039/d2ob00213b
日期:——
triflate (Sc(OTf)3) catalyzed, mild, and regioselective ring-opening reaction of donor–acceptor (D–A) cyclopropanes has been developed using sulfoximines for the synthesis of γ-sulfoximino malonic diesters. This protocol allows the synthesis of different N-alkyl sulfoximines in good to excellent yields (up to 94%) with broad functional group tolerance. In this process, N–H and C–C bonds are cleaved