Journal of the American Chemical Society
Communication
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(17) For a detailed cost comparison of NMe4F and CsF for similar
fluorination reactions, see ref 15.
(18) Dong, J.; Krasnova, L.; Finn, M. G.; Sharpless, K. B. Angew. Chem.,
Int. Ed. 2014, 53, 9430.
and inexpensive reagents represents a major advance relative to
existing aryl fluorination processes. Ab initio calculations
implicate a mechanism involving concerted C−O cleavage and
C−F bond formation in this transformation. Overall, we
anticipate that this method will find extensive application in the
synthesis of pharmaceutical and agrochemical target molecules in
both discovery and process development applications.
(19) Zhang, E.; Tang, J.; Li, S.; Wu, P.; Moses, J. E.; Sharpless, B. K.
Chem. - Eur. J. 2016, 22, 5692.
(20) Hanley, P. S.; Ober, M. S.; Krasovskiy, A. L.; Whiteker, G. T.;
Kruper, W. J. ACS Catal. 2015, 5, 5041.
(21) Hanley, P. S.; Clark, T. P.; Krasovskiy, A. L.; Ober, M. S.; O’Brien,
J. P.; Staton, T. S. ACS Catal. 2016, 6, 3515.
(22) Clark, J. H.; Wails, D.; Bastock, T. W. Aromatic Fluorination. CRC
Press: Boca Raton, FL, 1996.
ASSOCIATED CONTENT
■
S
* Supporting Information
The Supporting Information is available free of charge on the
(23) For evaluation of other fluoride sources and reaction solvents, see
Experimental and spectral data for all new compounds and
all reactions reported as well as computational details
(24) When 1 equiv of water was added to this reaction, the yield
dropped to <5%. As such, this and subsequent transformations were
conducted in dry DMF (from Alfa Aesar; AA43997K2) using anhydrous
NMe4F (from Aldrich; 459135). These commercial reagents were used
as received without further purification.
(25) For the rate of reaction with the corresponding aryl bromide and
(26) Adams, D. J.; Clark, J. H. Chem. Soc. Rev. 1999, 28, 225.
(27) After 24 h at 80 °C, the yield of 1-F from 1-NO2 erodes to 57%. By
GC−MS, a diaryl ether byproduct is observed.
(28) Sun, H.; DiMagno, S. G. Angew. Chem., Int. Ed. 2006, 45, 2720.
(29) For a more extensive comparison of different aryl chloride and
nitroarene substrates to the corresponding ArOFs, see Table S3.
(30) 1,4-Difluorobenzene was not observed in the reactions of either 8-
F or 9-F under our standard conditions (i.e., with 2 equiv of NMe4F).
(31) Grushin, V. V.; Marshall, W. J. Organometallics 2008, 27, 4825.
(32) For substrates with electron-withdrawing groups in the meta-
position, regioisomers consistent with benzyne intermediates were only
detected when the reactions were conducted at higher temperatures
(≥100 °C).
AUTHOR INFORMATION
■
Corresponding Author
ORCID
Notes
The authors declare the following competing financial inter-
est(s): The Dow Chemical Company has filed a patent
application on this chemistry.
ACKNOWLEDGMENTS
■
This work was supported by The Dow Chemical Company. We
gratefully acknowledge James R. Bour for helpful discussions.
(33) For electron-rich substrates, starting material remains after 24 h,
and longer reaction times do not improve the yield. In some cases, a
diaryl sulfate byproduct is detected by GC−MS.
(34) Hedayatullah, M.; Guy, A.; Denivelle, L. C. Acad. Sc. Paris 1974,
278, 57.
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D
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