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2.6.1.7 Palladium-Catalyzed Ligand-Directed C—H Fluorination of Benzamide Derivatives

DOI: 10.1055/sos-SD-208-00368

McMurtrey, K. B.; Sanford, M. S.Science of Synthesis: Cross Coupling and Heck-Type Reactions, (20132560.

A related procedure has recently been developed for the tetrakis(acetonitrile)palladium(II) trifluoromethanesulfonate catalyzed ligand-directed C—H fluorination of benzamides with 1-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate (NFTPT) (Scheme 7).[‌9‌] Variation of the amide nitrogen substituent enables the tuning of selectivity for mono- versus difluorination. Use of the 2,3,5,6-tetrafluoro-4-(trifluoromethyl)phenyl-substituted amides 13 results in >10:1 selectivity for monofluorination. Isolated yields of monofluorinated products 14 in this transformation range from 36 to 78%. The scope and functional group tolerance are similar to those of the related transformations in Sections 2.6.1.5 and 2.6.1.6.

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