N-Fluorobis [(perfluoroalkyl)sulfonyl]imides. Efficient reagents for the fluorination of 1,3-dicarbonyl derivatives

The Tautomeric Persistence of Electronically and Sterically Biased 2‐Quinolinones

“…According to Bumgardner et al, a fluorine atom at the 2-position of a cyclic 1,3-dicarbonyl compound does not noticeably alter the preference for the enol form whereas it reverses the equilibrium position and makes the keto form predominant upon fluorination of acyclic substrates. [50] This rule is at variance with earlier [51] but in agreement with later [52] findings. For example, the enol content of 3-fluoroacetonylacetone approximates 20 % [52] in contrast to the 80 % determined for the halogen-free analog.…”

“…[50] This rule is at variance with earlier [51] but in agreement with later [52] findings. For example, the enol content of 3-fluoroacetonylacetone approximates 20 % [52] in contrast to the 80 % determined for the halogen-free analog. [53] Ethyl 2-fluoroacetoacetate and ethyl 2-fluorobenzoylacetate are enolized to the extent of 4 % and Ͻ 3 %, respectively, [52] less than half as much as the corresponding parent compounds.…”

“…For example, the enol content of 3-fluoroacetonylacetone approximates 20 % [52] in contrast to the 80 % determined for the halogen-free analog. [53] Ethyl 2-fluoroacetoacetate and ethyl 2-fluorobenzoylacetate are enolized to the extent of 4 % and Ͻ 3 %, respectively, [52] less than half as much as the corresponding parent compounds. [53][54] Spectacular substituent effects on the oxo/enol equilibria of polyfluoroketones were reported by Lemal et al [55] Whereas the enol forms of both cyclopentanone and 3H-heptafluoro-2-butanone were present only in undetectably small concentrations, 2H-nonafluorocyclohexanone, 2,2-H 2 -hexafluorocyclopentanone, 2H-heptafluoropentanone and 2H-pentafluorocyclobutanone were enolized to the extent of 25, 13, 99 and Ͼ99.5 %.…”

Microwave-assisted rapid electrophilic fluorination of 1,3-dicarbonyl derivatives with Selectfluor®

“…There continues to be considerable interest in the electrophilic fluorination of 1,3-dicarbonyl compounds since the a-fluoro carbonyl compounds are valuable building blocks in constructing potentially useful biological compounds [2][3][4][5][6][7][8][9][10][11][12][13][14]. While 1,3-dicarbonyl derivatives can be fluorinated directly by a variety of electrophilic fluorinating agents, 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo [2.2.2]-octane bis(tetrafluoroborate) (Selectfluor 1 , F-TED-A-BF 4 , 1), first reported by Banks et al [15,16], is an efficient site-selective, commercially available electrophilic fluorinating agent.…”

Direct Access to α,α‐Difluoroacylated Arenes by Palladium‐Catalyzed Carbonylation of (Hetero)Aryl Boronic Acid Derivatives

“…Such structures are not widely found and their overall absence in the pharmaceutical portfolio may be related to the challenges in their preparation. [7] Nevertheless, the a,a-difluorinated dicarbonyl moiety remains an excellent entry point for accessing a variety of functionalities and ring structures containing fluorine. For these reasons, we investigated the three-component palladium-catalyzed carbonylative a-arylation of a-silylated-a,adifluoroacetamides to deliver structures such as the ketone 1 (Scheme 1 c).…”