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Direct construction of the piperazine scaffolds with multiple functionalities remains important yet challenging. Herein, a silver-catalyzed formal [3 + 3] heteroannulation of aziridines with 3-aminoacrylates via ring-opening and vinyl C(sp)-H amination for the direct synthesis of tetrasubstituted 1,4,5,6-tetrahydropyrazines is reported. Upon the catalytic activation of the silver Lewis acid, this protocol enables the formation of two new C-N bonds through selective nucleophilic ring-opening and C-H aminative cyclization cascades, featuring a broad substrate scope and a good functional group tolerance with excellent selectivity.
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http://dx.doi.org/10.1021/acs.orglett.5c00952 | DOI Listing |
Org Lett
May 2025
State Key Laboratory Base of Eco-Chemical Engineering, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao 266042, China.
Direct construction of the piperazine scaffolds with multiple functionalities remains important yet challenging. Herein, a silver-catalyzed formal [3 + 3] heteroannulation of aziridines with 3-aminoacrylates via ring-opening and vinyl C(sp)-H amination for the direct synthesis of tetrasubstituted 1,4,5,6-tetrahydropyrazines is reported. Upon the catalytic activation of the silver Lewis acid, this protocol enables the formation of two new C-N bonds through selective nucleophilic ring-opening and C-H aminative cyclization cascades, featuring a broad substrate scope and a good functional group tolerance with excellent selectivity.
View Article and Find Full Text PDFOrg Lett
April 2025
Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education and School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, People's Republic of China.
Cycloadditions of bicyclobutanes with two- or three-atom reaction partners have been widely exploited to access bicyclo[2.1.1]hexanes and bicyclo[3.
View Article and Find Full Text PDFJ Org Chem
July 2023
State Key Laboratory, College of Chemistry, Institute of Elemento-Organic Chemistry, Nankai University, Weijin Road 94, Tianjin 300071, China.
Herein, we report a mild, one-pot method for silver-catalyzed tandem cycloisomerization/[5 + 2] cycloaddition reactions between readily accessible cyclopropyl-tethered allenyl ketones and benzopyranone-derived oxidopyrylium ylides. The reactions proceed a cyclobutene-fused furan intermediate generated by a cycloisomerization/1,2-carbene transfer/ring-expansion cascade. This method, which features an unprecedented formal [5 + 2] cycloaddition, delivers good to excellent yields of structurally complex bibridged benzocycloheptanones bearing a strained cyclobutane ring and an -bridged ring.
View Article and Find Full Text PDFOrg Lett
November 2022
Jilin Province Key Laboratory of Organic Functional Molecular Design and Synthesis, Department of Chemistry, Northeast Normal University, Changchun, Jilin 130024, China.
We describe the silver-catalyzed formal insertion of a vinylcarbene into unstrained C(CO)-C bonds of 1,3-diketones using vinyl--triftosylhydrazones as vinylcarbene precursors. This method allows the rapid synthesis of otherwise inaccessible 2-vinyl-substituted 1,4-diketones from relatively simple substrates. This mild catalytic protocol exhibits a good functional group tolerance and substrate scope and allows for good chemoselectivity control.
View Article and Find Full Text PDFOrg Lett
January 2022
Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
Herein we have developed the silver-catalyzed electronic- and steric-controlled intramolecular formal [2 + 2]-cycloaddition of alkyne-tethered cyclohexadienones. Substrates with electron-rich alkynes and a less hindered quaternary carbon center afford tricyclic fused cyclobutenes through 1,7-enyne cyclization. In contrast, the formation of dihydrofurans was observed from electron-deficient alkynes via proton abstraction/C-O bond cleavage.
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