[10405-27-3]  · F2HN  · Difluoramine  · (MW 53.01)

(reagent for introducing difluoroamine groups into organic molecules;1-3 synthesis of diazirines;4 deamination of primary amines5)

Alternate Name: fluoroimide.

Physical Data: bp -23 °C.

Preparative Methods: difluoramine can be generated from tetrafluorohydrazine, which is made by reaction of NF3 with various metals at 375 °C.6 Conversion into difluoramine is accomplished by heating tetrafluorohydrazine with Thiophenol in an evacuated bulb.7 Difluoramine is also generated by heating N,N-difluorourea with conc. Sulfuric Acid.8

Handling, Storage, and Precautions: is shock sensitive. Reactions should be carried out in a fume hood.

Synthesis of Diazirines.

The reaction of t-octylazomethine or t-butylazomethine with difluoramine has been shown to give diazirine (eq 1).4 Other substituted imines produce substituted diazirines, a-fluoroazo compounds, or a-fluoroalkylidene hydrazines in relative yields dependent upon the structure of the imine (eq 2).9

Reactions of Carbonyl Compounds with Difluoramine.

Difluoramine reacts with aldehydes and ketones to give a-difluoroamino alcohols of varying stability (eq 3).1 Aliphatic ketones and aldehydes react with difluoramine in H2SO4 or oleum with replacement of the carbonyl by two difluoroamino groups (eq 4).2

Carbocation precursors in the g-position cyclize to give difluoroamino substituted lactones (eq 5) and tetrahydrofurans.2 Michael addition of difluoramine takes place with a,b-unsaturated carbonyl compounds (eq 6).

Difluoramine undergoes reaction with a-hydroxy ketones and 1,2-diketones in fuming H2SO4 to form 4-difluoroamino or 4,5-bis(difluoroamino) substituted 1,3-dioxa-2-thiolane 2,2-dioxides, respectively (eq 7).8 Difluoramine is generated in situ by the interaction of N,N-difluorourea with concentrated H2SO4 in these reactions. Difluoramine reacts vigorously with acetone phenylhydrazone to give N-fluorodimethylketimine (eq 8).10

Reaction of Alkynes with Difluoramine.

The reaction of 3-hexyne with difluoroamine, catalyzed by the Boron Trifluoride complex of Phosphoric Acid, gives 3-hexanone, 3,3-bis(difluoroamino)hexane, 3-difluoroamino-3-fluorohexane, and N-(a-difluoroaminopropyl)propionamide in various yields.11

Alkylation of Difluoramine.

Difluoramine can be alkylated with an alkyl halide, alcohol, alkene, or ether to yield difluoroamino substituted alkanes.3 Ether derivatives require no catalysis; with alkenes the boron trifluoride complex of phosphoric acid or H2SO4 is used (eq 9). Yields are sensitive to time and temperature and range from 50-60 % for the alkene reactions to quantitative for the ethers.

Deamination of Primary Amines.

Difluoramine converts primary amines to alkanes (eq 10). Secondary amines, such as aziridine, azetidine, and dibenzylamine, react with difluoramine to yield, respectively, ethylene (eq 11), cyclopropane, and bibenzyl by releasing nitrogen and coupling the remaining fragments.5,12

Reaction of C-Nitroso Compounds with Difluoramine.

The reaction of difluoramine with C-nitroso compounds affords N-substituted N-fluorodiimide N-oxides (eq 12); N-aryl substituted N-fluorodiimide N-oxides can be converted to azoxy compounds with Grignard reagents (eq 12).13

1. Freeman, J. P.; Graham, W. H.; Parker, C. O. JACS 1968, 90, 121.
2. Baum, K. JACS 1968, 90, 7083.
3. Graham, W. H.; Freeman, J. P. JACS 1967, 89, 716.
4. Graham, W. H. JACS 1962, 84, 1063.
5. Bumgardner, C. L.; Martin, K. J.; Freeman, J. P. JACS 1963, 85, 97.
6. Colburn, C. B.; Kennedy, A. JACS 1958, 80, 5004.
7. Freeman, J. P.; Kennedy, A.; Colburn, C. B. JACS 1960, 82, 5304.
8. Mueller, K. F.; Cziesla, M. J. JOC 1969, 34, 917.
9. Graham, W. H. JACS 1966, 88, 4677.
10. Bumgardner, C. L.; Freeman, J. P. TL 1966, 5547.
11. Baum, K. JACS 1968, 90, 7089.
12. Bumgardner, C. L.; Freeman, J. P. JACS 1964, 86, 2233.
13. Stevens, T. E.; Freeman, J. P. JOC 1964, 29, 2279.

Ender Erdik

Ankara University, Turkey

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