Ultrafast Click Chemistry with Fluorosydnones. Issue 39 (25th August 2016)

• Record Type: Journal Article
• Authors: Liu, Hui; Audisio, Davide; Plougastel, Lucie; Decuypere, Elodie; Buisson, David‐Alexandre; Koniev, Oleksandr; Kolodych, Sergii; Wagner, Alain; Elhabiri, Mourad; Krzyczmonik, Anna; Forsback, Sarita; Solin, Olof; Gouverneur, Véronique; Taran, Frédéric
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 39(2016)
• Page Start: 12073
• Page End: 12077
• Publication Date: 2016-08-25
• Subjects: click chemistry -- electrophilic fluorination -- fluorine-18 -- kinetics -- radiolabeling; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201606495
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: We report the synthesis and reactivity of 4‐fluorosydnones, a unique class of mesoionic dipoles displaying exquisite reactivity towards both copper‐catalyzed and strain‐promoted cycloaddition reactions with alkynes. Synthetic access to these new mesoionic compounds was granted by electrophilic fluorination of σ‐sydnone Pd II precursors in the presence of Selectfluor. Their reactions with terminal and cyclic alkynes were found to proceed very rapidly and selectively, affording 5‐fluoro‐1, 4‐pyrazoles with bimolecular rate constants up to 10 4 m −1 s −1, surpassing those documented in the literature with cycloalkynes. Kinetic studies were carried out to unravel the mechanism of the reaction, and the value of 4‐fluorosydnones was further highlighted by successful radiolabeling with [ 18 F]Selectfluor. Abstract : Fast and fluorious : Fluorosydnones are extremely reactive towards copper‐catalyzed cycloaddition reactions with terminal alkynes and copper‐free reactions with cycloalkynes. These highly reactive clickable reagents were prepared by electrophilic fluorination of sydnone Pd II precursors in the presence of Selectfluor.