Categories: C-F Bond Formation >
Synthesis of fluoroalkanes
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Recent Literature
Aminodifluorosulfinium tetrafluoroborate salts act as efficient
deoxofluorinating reagents when promoted by an exogenous fluoride source and, in
most cases, exhibited greater selectivity by providing less elimination
byproduct as compared to DAST and Deoxo-Fluor. Aminodifluorosulfinium
tetrafluoroborates are storage-stable, and unlike DAST and Deoxo-Fluor do not
react violently with water.
F. Beaulieu, L.-P. Beauregard, G. Courchesne, M. Couturier, F. LaFlamme, A.
L'Heureux, Org. Lett., 2009,
11, 5050-5053.
Direct fluorination of primary and secondary alcohols by a combination of
perfluoro-1-butanesulfonyl fluoride (PBSF) and tetrabutylammonium
triphenyldifluorosilicate (TBAT) under mild conditions provides the
corresponding fluorides in high yields with inversion at the reaction center and
suppressed elimination side reactions.
X. Zhao, W. Zhuang, D. Fang, X. Xue, J. Zhou, Synlett, 2009,
779-782.
A nucleophilic fluorination of triflates by weakly basic tetrabutylammonium
bifluoride provides excellent yields with minimal formation of
elimination-derived side products. Most primary and secondary hydroxyl groups
are excellent substrates, but benzylic and aldol-type secondary hydroxyl groups
give poor yields as a result of the instability of their triflates.
K.-Y. Kim, B. C. Kim, H. B. Lee, H. Shin, J. Org. Chem., 2008,
73, 8106-8108.
K.-Y. Kim, B. C. Kim, H. B. Lee, H. Shin, J. Org. Chem., 2008,
73, 8106-8108.
Bis(2-methoxyethyl)aminosulfur trifluoride (Deoxo-Fluor
reagent) is a new deoxofluorinating agent that is much more thermally stable
than DAST (C2H5)2NSF3. It is effective for the conversion of
alcohols to alkyl fluorides, aldehydes and ketones to the corresponding
gem-difluorides, and carboxylic acids to the trifluoromethyl derivatives with,
in some cases, superior performance compared to DAST.
G. S. Lal, G. P. Pez, R. J. Pesaresi, F. M. Prozonic, H. Cheng, J. Org.
Chem., 1999,
7048-7054.
A synergistic effect in nucleophilic fluorination has been demonstrated for the
molecular combination of an ionic liquid and a tert-alcohol. Consequently,
these functionalized ILs not only increase the nucleophilic reactivities of the
fluoride anion but also remarkably reduce the olefin byproduct.
S. S. Shinde, B. S. Lee, D. Y. Chi, Org. Lett., 2008,
10, 733-735.
Nucleophilic fluorination using CsF or alkali metal fluorides was completed in
short reaction time in the presence of [bmim][BF4] affording the
desired products without any byproducts. Facile nucleophilic substitutions such
as halogenations, acetoxylation, nitrilation, and alkoxylations in the presence
of ionic liquids provided the desired products in good yields.
D. W. Kim, C. E. Song, D. Y. Chi, J. Org. Chem., 2003, 68,
4281-4285.
Fluorinations of epoxides and alkyl mesylates can be effectively achieved by
reaction with Et3N • 3 HF under microwave irradiation. The
reactions were completed in a few minutes and the use of large excess of
reagents could be avoided.
T. Inagaki, T. Fukuhara, S. Hara, Synthesis,
2003, 1157-1159.
Halofluorination of alkenes in the presence of trihaloisocyanuric acids and HF•pyridine
results in the formation of vicinal halofluoroalkanes in good yields. The
reaction is regioselective leading to Markovnikov-oriented products and the
halofluorinated adducts follow anti-addition in the case of cyclohexene
and 1-methylcyclohexene.
L. T. C. Crespo, R. da S. Ribeiro, M. S. S. de Mattos, P. M. Esteves, Synthesis, 2010,
2379-2382.
