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.
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http://dx.doi.org/10.1021/acs.joc.3c00436 | DOI Listing |
Acc Chem Res
November 2024
Department of Chemistry, Seoul National University, Seoul 08826, Korea (South).
Chem Commun (Camb)
October 2024
State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, People's Republic of China.
A silver-catalyzed cascade cyclization strategy has been developed for the synthesis of 4-aminotetrahydrocarbazole, a common core structure found in various alkaloids. This target molecule can be synthesized through a one-step tandem cyclization reaction, thereby eliminating the need for a prior synthesis of tetrahydrocarbazole. Furthermore, the use of chiral -butylsulfinamide facilitates chiral resolution of the resulting product.
View Article and Find Full Text PDFOrg Lett
June 2024
School of Pharmacy, Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 611137, P. R. China.
Here, we present a versatile, silver-catalyzed multi-auto-tandem reaction involving enamines, alkynals, and nucleophiles, utilizing the highly reactive intermediate azafulvenium. This method allows for flexible and switchable regiodivergent reactions through either intermolecular or intramolecular nucleophilic attacks, which can be controlled by adjusting the catalytic conditions. A range of site-specific functionalized or polycyclic fused pyrrole products were efficiently produced with a high level of chemocontrol.
View Article and Find Full Text PDFNat Commun
March 2024
Department of Chemistry, Northeast Normal University, Changchun, 130024, China.
Epoxides, as a prominent small ring O-heterocyclic and the privileged pharmacophores for medicinal chemistry, have recently represented an ideal substrate for the development of single-atom replacements. The previous O-to-C replacement strategy for epoxides to date typically requires high temperatures to achieve low yields and lacks substrate range and functional group tolerance, so achieving this oxygen-carbon exchange remains a formidable challenge. Here, we report a silver-catalyzed direct conversion of epoxides into trifluoromethylcyclopropanes in a single step using trifluoromethyl N-triftosylhydrazones as carbene precursors, thereby achieving oxygen-carbon exchange via a tandem deoxygenation/[2 + 1] cycloaddition.
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.
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