Geminal F-oxyfluorination of diazoketones was performed in the presence of rhodium mediators. The reactions were performed using a hypervalent iodine-based [F]fluoro-benziodoxole reagent. By this methodology various α-[F]fluoro ethers were obtained in high radiochemical yield (up to 98%) and molar activity (216 GBq μmol).
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http://dx.doi.org/10.1039/c9cc06905d | DOI Listing |
Org Lett
October 2024
Shanghai Key Laboratory of Functional Materials Chemistry, Key Laboratory for Advanced Materials, School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai 200237, China.
A novel substrate-regulated [4+1] annulation of α-imidoyl sulfoxonium ylides with diazoketones under catalyst-free conditions is described. The reaction proceeds through a coupling of sulfoxonium ylides and in situ-generated ketenes to form the key reactive zwitterionic intermediates, followed by selective formation of C-C or C-O bonds to achieve five-membered ring systems. The cascade reaction permits the direct synthesis of synthetically useful 2-indanones and 3(2)-furanones, which expands the reaction pattern of sulfoxonium ylides in annulation transformation.
View Article and Find Full Text PDFJ Org Chem
October 2024
Aragen Life Sciences Ltd., Bengaluru 562106, India.
Photoactivatable (PA) rhodamine dyes are widely used in single-molecule tracking (SMT) and a variety of other fluorescence-based imaging modalities. One of the most commonly employed scaffolds uses a diazoketone to lock the rhodamine in the nonfluorescent closed form, which can be activated with 405 nm light. However, poor properties of previously reported dyes require significant washing, which can be resource- and cost-intensive, especially when performing microscopy in a large scale and high-throughput fashion.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
June 2024
School of Chemistry and Molecular Engineering, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, P. R. China.
We here reported a highly stereoselective method for the synthesis of polysubstituted conjugated dienes from α-aryl α-diazo alkynyl ketones and pyrazole-substituted unsymmetric aminals under mild conditions, which was promoted by photo-irridation and involved with 1,6-dipolar intermediate and quadruple sigmatropic rearrangements, was successfully developed. In this transformation, the cleavage of four bonds and the recombination of five bonds were implemented in one operational step. This protocol provided a modular tool for constructing dienes from amines, pyrazoles and α-alkynyl-α-diazoketones in one-pot manner.
View Article and Find Full Text PDFJ Org Chem
April 2024
Pharmaceutical Research Institute, Wuhan Institute of Technology, Wuhan 430205, China.
A novel method is described for the synthesis of 2,4-disubstituted oxazole and thiazole derivates via the coupling of α-diazoketones with (thio)amides or thioureas using trifluoromethanesulfonic acid (TfOH) as a catalyst. This protocol is characterized by mild reaction conditions, metal-free, and simplicity and also features good functional group tolerance, good to excellent yields, and a broad substrate scope with more than 40 examples. Experimental studies suggest a mechanism involving 2-oxo-2-phenylethyl trifluoromethanesulfonate as the key intermediate.
View Article and Find Full Text PDFNat Commun
December 2023
Department of Chemistry, University of Rochester, Rochester, NY, 14627, USA.
Hemoproteins have recently emerged as promising biocatalysts for new-to-nature carbene transfer reactions. However, mechanistic understanding of the interplay between productive and unproductive pathways in these processes is limited. Using spectroscopic, structural, and computational methods, we investigate the mechanism of a myoglobin-catalyzed cyclopropanation reaction with diazoketones.
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