Ultrafast click chemistry with fluorosydnones.

Journal article

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.

Authors: Liu, H; Audisio, D; Plougastel, L; Decuypere, E; Buisson, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Angewandte Chemie International Edition
• Volume: 55
• Issue: 39
• Pages: 12073-12077
• Publication date: 2016-08-01
• DOI: 10.1002/anie.201606495
• EISSN: 1521-3773
• ISSN: 1433-7851
• Pmid: 27560312
• Language: English
• Keywords: radiolabeling; kinetics; click chemistry; fluorine-18; electrophilic fluorination