Ultrafast Click Chemistry with Fluorosydnones
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 fluor...
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Published in | Angewandte Chemie (International ed.) Vol. 55; no. 39; pp. 12073 - 12077 |
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Main Authors | , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
WEINHEIM
Blackwell Publishing Ltd
19.09.2016
Wiley Wiley Subscription Services, Inc |
Edition | International ed. in English |
Subjects | |
Online Access | Get full text |
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Summary: | 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 PdII 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 104 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 [18F]Selectfluor.
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 PdII precursors in the presence of Selectfluor. |
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Bibliography: | istex:F356E937704BD02B628E8D04E69E99B96B078E51 French Research National Agency - No. ANR-14-CE06-0004 Academy of Finland - No. 266891 EC - No. FP7-PEOPLE-2012-ITN-RADIOMI-316882 ArticleID:ANIE201606495 ark:/67375/WNG-1XLH0LS1-P ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1433-7851 1521-3773 |
DOI: | 10.1002/anie.201606495 |