A new class of rhodium-catalyzed, C-H activation triggered [3 + 2] annulations of aromatic aldimines or ketimines and maleimides was reported in this study. A broad scope of general imines without electron-withdrawing groups were successfully activated and could effectively react with N-substituted maleimide to afford pericyclic, multichiral centered amines in good yields and with excellent diastereoselectivity.
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http://dx.doi.org/10.1021/acs.orglett.8b02671 | DOI Listing |
Molecules
January 2025
School of Chemistry and Materials Engineering, Huainan Normal University, Huainan 232038, China.
Efficient access to pyranoisoquinoline derivatives via rhodium-catalyzed double C-H functionalization of phenyl oxadiazoles and diazo compounds has been developed. Two C-C bonds and one C-O and C-N bond formation was realized by this tandem reaction, along with the formation of two heterocycles, affording diversified pyran-fused isoquinolines in moderate to good yields with broad functional group tolerance under mild reaction conditions.
View Article and Find Full Text PDFOrg Lett
January 2025
Pfizer Oncology Medicinal Chemistry, 10770 Science Center Drive, San Diego, California 92121, United States.
General procedures for the rhodium-catalyzed annulation of aryl/heteroaryl -pivaloyl hydroxamic acids and norbornadiene have been developed. Employing norbornadiene as an acetylene equivalent enables utilization of diverse heterocyclic substrates for this transformation which fail to react or undergo competitive Lossen rearrangement under previously reported conditions. Microwave heating significantly reduces reaction times compared to conventional protocols and allows a one-step process to be realized.
View Article and Find Full Text PDFRSC Adv
December 2024
Natural and Medical Sciences Research Center (NMSRC), University of Nizwa Nizwa 616 Sulanate of Oman.
Diazo compounds are known to be good coupling partners in the synthesis of heterocycles, carbocycles and functionalized molecules a rhodium carbene-based strategy. Many heterocyclic and carbocyclic compounds, including isoquinolones and isocoumarins, quinoxalines, indoles, pyrrones, benzothazines, enaminones, benzenes and seven-membered rings, can be constructed using this rhodium-catalyzed system. The reaction mechanism involves C-H activation, carbene insertion and an annulation/functionalization sequence.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
School of Pharmacy, Guangdong Pharmaceutical University, Guangzhou, 510006, P. R. China.
A Rh(III)-catalyzed C-H α-fluoroalkenylation/annulation of β-ketosulfoxonium ylides with 2,2-difluorovinyl tosylate/oxadiazolones was realized, which afforded various -fluoroalkenylation β-ketosulfoxonium ylides with high -selectivity and diverse oxadiazolone fused-isoquinolines. This protocol featured mild conditions, broad substrate scope, and functional-group compatibility. In addition, scale-up synthesis, related applications and preliminary mechanistic explorations were also accomplished.
View Article and Find Full Text PDFChem Asian J
January 2025
Department of Chemistry, Indian Institute of Science Education & Research, 462066, Bhopal, Madhya Pradesh, India.
A new approach for the synthetically important γ-functionalized enals has been developed. The strategy involves rhodium-catalyzed direct C-C & C-S bond forming site-selective γ-difunctionalization of diazoenals with aryl propargyl sulfides via sulfur ylide [2,3] sigmatropic rearrangement, resulting in the highly functionalized γ-allenyl(sulfanyl)enals in excellent yield at ambient temperature. This highly versatile approach constitutes a viable alternative to the remote carbonyl-directed γ-functionalization of unmodified enals which suffer from competitive side reactions.
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