Herein, we report a cascade annulation of readily available isocyanobiaryls with simple aldehydes photoredox catalysis, providing a straightforward approach towards valuable 6-hydroxyalkylated phenanthridines. Mechanistic studies indicated the generation of a key acyl radical from aldehydes by hydrogen atom abstraction with a bromine radical. This protocol exhibits exceptional chemoselectivity, excellent tolerance of various functional groups and mild reaction conditions. Its synthetic utility was demonstrated by a gram-scale reaction and various facile manipulations of the free hydroxyl group to furnish diverse phenanthridine derivatives.
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http://dx.doi.org/10.1039/d4ob02085e | DOI Listing |
Org Biomol Chem
January 2025
Key Laboratory for Green Organic Synthesis and Application of Hunan Province, Key Laboratory of Environmentally Friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105, China.
Herein, we report a cascade annulation of readily available isocyanobiaryls with simple aldehydes photoredox catalysis, providing a straightforward approach towards valuable 6-hydroxyalkylated phenanthridines. Mechanistic studies indicated the generation of a key acyl radical from aldehydes by hydrogen atom abstraction with a bromine radical. This protocol exhibits exceptional chemoselectivity, excellent tolerance of various functional groups and mild reaction conditions.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Mulliken Center for Theoretical Chemistry University of Bonn Beringstr. 4, 53115 Bonn, Germany.
A novel HSO-catalyzed ANRORC-type rearrangement of pyrazinones to imidazoles proceeding through pyridazino[]annulation with simultaneous introduction of a pyrazole ring at position 2 of the imidazole system has been developed, which offers efficient and expedited access to new biheterocyclic systems - 2-(pyrazol-3-ul)imidazoles and 2-(pyrazol-3-yl)imidazo[4,5-]pyridazines. Diverse bi--heterocyclic systems with the imidazo[4,5-]pyridazine-4,7-diamine moiety could be obtained in excellent yield when 5,6-dicyano-3-(2-oxo-2-ethyl)pyrazin-2(1)-ones interact with hydrazines the selective spiro-formation in a tandem ring-opening/ring-closing process, which allowed the simultaneous construction of five new C-N bonds. This new method is compatible with an array of functional groups, proceeds under mild reaction conditions with the involvement of commercially available reagents.
View Article and Find Full Text PDFJ Org Chem
January 2025
School of Chemistry & Materials Science, Jiangsu Normal University, Xuzhou 221116, China.
1-Isochromene scaffolds are ubiquitous in natural products and significant bioactive molecules. Although several methods for these molecular syntheses have been developed, reports on the efficient construction of iminated isochromenes are still rather limited. Herein, we report a new Cu(II)-catalyzed annulation and sulfonylimination cascade of α-carbonyl-γ-alkynyl sulfoxonium ylides with sulfamides, enabling direct C-C σ-bond elimination to furnish iminated ()-1-isochromenes in 51-97% yields.
View Article and Find Full Text PDFChem Asian J
January 2025
Key Laboratory of Chemical Biology of Fujian Province, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
The direct construction of polycyclic arenes through ring formation using simple building blocks is highly appealing but remains challenging in organic chemistry. In this study, we introduce an efficient cascade reaction that combines dearomatizing photocyclization with oxidative aromatization, driven by organophotocatalysis. Conducted under mild, transition-metal-free conditions, this reaction seamlessly converts styrene derivatives into a diverse array of functionalized polycyclic aromatic compounds with good yields and regioselectivity.
View Article and Find Full Text PDFJ Org Chem
January 2025
Applied Chemistry and Chemical Engineering, Graduate School of Engineering, Kogakuin University, Nakano 2665-1, Hachioji, Tokyo 192-0015, Japan.
The cascade aza-Prins/Friedel-Crafts reaction of homocinnamyloxycarbamate with electron-rich aromatic aldehydes has been successfully established. Most of the aromatic aldehydes react with the carbamate stereoselectively to generate -hydroindeno-1,2-oxazinanes. However, the cascade reactions of benzaldehydes bearing two methoxy groups at the -positions exhibit a unique stereochemical profile.
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