Chiral Lewis acid-catalyzed asymmetric alcohol addition reactions to cyclic carbonyl ylides generated from N-(α-diazocarbonyl)-2-oxazolidinones featuring a dual catalytic system are reported. Construction of a chiral quaternary heteroatom-substituted carbon center was accomplished in which the unique heterobicycles were obtained in good yields with high stereoselection. The alcohol adducts were successfully converted to optically active oxazolidine-2,4-diones by hydrolysis. Mechanistic studies by DFT calculations revealed that alcohols could be activated by Lewis acids, enabling enantioselective protonation of the carbonyl ylides.
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Org Lett
January 2025
State Key Laboratory of Applied Organic Chemistry & College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000, P. R. China.
Herein, we present a visible-light-induced protocol for the synthesis of highly functionalized oxo-bridged oxocine skeletons. This method generates carbenes via visible-light-induced ortho-acyl diazo compounds, which are rapidly intercepted by the oxygen atom of an intermolecular acyl group to form a cyclic 1,3-dipole. The in situ generated highly reactive 1,3-dipole undergoes a facile formal [4 + 3] cycloaddition with alkenyl pyrazolinone, yielding [4.
View Article and Find Full Text PDFBeilstein J Org Chem
December 2024
Department of Chemistry, University of Waterloo, 200 University Ave W., Waterloo, Ontario, Canada.
A novel study on the hypervalent iodine-mediated polyfluoroalkylation of sulfoxonium ylides was developed. Sulfoxonium ylides, known for their versatility and stability, are promising substrates for numerous transformations in synthetic chemistry. This report demonstrates the successful derivatization of sulfoxonium ylides with trifluoroethyl or tetrafluoropropyl groups, and provides valuable insights into the scope and limitations of this approach.
View Article and Find Full Text PDFSci Adv
November 2024
Department of Chemistry, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea.
Geminal bromofluoroalkenes are an important subclass of versatile organic interhalide, which can serve as useful synthetic precursors to monofluoroalkenes that are valuable amide group isosteres. Nonetheless, despite the vast advancement of olefination methodologies, the broadly applicable stereoselective synthesis remained elusive for geminal bromofluoroalkenes before our work. In particular, the seemingly straightforward Wittig-type approach with interhalogenated phosphorus ylide has been unsuccessful because of the difficulty in the diastereoselective oxaphosphetane formation.
View Article and Find Full Text PDFChem Commun (Camb)
November 2024
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati-781039, India.
The cascade carbon-carbon and carbon-nitrogen bond formation between generated carbonyl ylides and azaoxyallyl cations, facilitated by Rh-catalysis and a base, has been achieved to furnish oxa-benzo[]azepin-3-ones. Substrate scope, functional group diversity, scale-up and post-synthetic utilities are the important practical features.
View Article and Find Full Text PDFChem Sci
October 2024
State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University Changsha Hunan 410082 P. R. China
The advance of organic synthesis and the discovery of novel chemical transformations are often propelled by the rational programming of various bond-forming mechanisms and sequences that involve delicate reactive intermediates. In this study, we present an innovative Rh(ii)-catalyzed asymmetric three-component cascade reaction involving I/P-hybrid ylides, aldehydes, and carboxylic acids for the synthesis of 1,3-dioxoles with moderate to good yields and high enantioselectivity. This method utilizes I/P-hybrid ylides as carbene precursors to form α-P-Rh-carbenes, which initiate the formation of carbonyl ylides, followed by stereoselective cyclization with carboxylate anions and an intramolecular Wittig olefination cascade, ultimately resulting in the modular assembly of chiral 1,3-dioxoles.
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