An Al(OTf)3 -catalyzed intramolecular cascade ring-opening benzannulation of 2,3-dihydrofuran O,O- and N,O-acetals is described. The cascade sequence involves the dihydrofuran ring-opening by acetal hydrolysis, an intramolecular Prins-type cyclization, and aromatization to generate an array of benzo-fused (hetero)aromatic systems in up to 95 % yield. This method represents the first example of dihydrofuran acetal usage in benzannulation reactions. The approach provides excellent regiocontrol based on the choice of alkenes used to form the requisite dihydrofuran acetals.
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http://dx.doi.org/10.1002/chem.201601954 | DOI Listing |
J Colloid Interface Sci
January 2025
College of Chemistry, Soochow University, Suzhou 215123, PR China. Electronic address:
In the manipulation of π-conjugated organic polymer, strategic alterations to the polymerization cascade facilitate the integration of donor (D) and acceptor (A) entities within the polymer's backbone. Such control is instrumental in broadening the photoresponse spectrum, enhancing photoinduced charge separation, and augmenting the efficiency of charge transfer processes. The oxygen-containing amino group (-ONH) was innovatively grafted into the polymerization process of the triazine-heptazine ring skeleton, and the -ONH was used as a capping agent to change the chain bonding in the polymerization process, thus a new intramolecular D-A structure was successfully constructed.
View Article and Find Full Text PDFJ Org Chem
January 2025
Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation, School of Pharmacy, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, Hubei 430030, People's Republic of China.
A novel copper-catalyzed formal diastereoselective [4 + 3] cycloaddition of 2-arylaziridines and 2-substituted cyclopentadiene was developed. This transformation provided an efficient protocol for the assembly of a highly strained bridged azabicyclo[3.2.
View Article and Find Full Text PDFChem Commun (Camb)
January 2025
Medicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, Lucknow, Uttar Pradesh 226031, India.
Biaryl motifs are essential structural features in several drugs and functional molecules. Cyclic diaryliodonium has been scarcely explored as a bifunctional agent compared to ring opening and annulation reactions. Herein, a three-component cascade approach is developed to synthesize bifunctionalized biaryls employing cyclic diaryliodoniums as a biarylating agent.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China.
Here, we report the enantioselective total syntheses of four diepoxy--kaurane diterpenoids including (-)-Macrocalin B, (-)-Acetyl-macrocalin B, and (-)-Isoadenolin A and the revised structure of (-)-Phyllostacin I, which hinges on the strategic design of a regioselective and stereospecific trapping of a highly reactive [3.2.1]-bridgehead enone intermediate via a tethered intramolecular Diels-Alder reaction.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva 841051, Israel.
Triplet 1,4-spiro[2.4]heptadiyl () has been shown experimentally to undergo rapid ring-opening and subsequent 1,2-hydrogen shift upon generation via photolysis of a diazene precursor at cryogenic temperatures. Modern computational tools elucidate the potential energy surface and kinetics behind this cascade reaction, disproving the earlier hypothesized mechanism invoking hot molecule effects in the first ring-opening step and tunneling in the second hydrogen transfer step.
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