G. Vla´d et al. / Tetrahedron Letters 46 (2005) 8605–8608
8607
42; (e) Alvey, L. J.; Rutherford, D.; Juliette, J. J. J.;
Gladysz, J. A. J. Org. Chem. 1998, 63, 6302–6308; (f)
groups are soluble in dichloromethane, and insoluble in
diethyl ether and apolar organic solvents.16
´
Alvey, L. J.; Meier, R.; Soos, T.; Bernatis, P.; Gladysz,
J. A. Eur. J. Inorg. Chem. 2000, 1975–1983.
7. Kampa, J. J.; Nail, J. W.; Lagow, R. J. Angew. Chem.
1995, 107, 1361–1364.
8. Battle, S. L. Ph.D. Thesis, Universityof Texas, Austin,
TX, 1993.
The fluorous tertiaryphosphines were obtained in 86–
89% yield by reduction of the [RFX(CH2)A]2-
[RFY(CH2)3]P@O derivatives, as reported byGladsyz
and co-workers,6e using trichlorosilane (HSiCl3) in
trifluoromethyl-benzene (BTF). Since the resulting
phosphines were expected to be soluble in fluorous sol-
vents, we used fluorous extraction during the work-up
procedure. The product phosphines are colorless or
slightlyyellow viscous oils ([R F4(CH2)3]2[RF8(CH2)3]P,
[RF8(CH2)2]2[RF6(CH2)3]P, [RF6(CH2)3]3P) or a white
solid ([RF8(CH2)3]3P).17
´
9. (a) Jiao, H.; Le Stang, S.; Soos, T.; Meier, R.; Kowski, K.;
Rademacher, P.; Jafarpour, L.; Hamard, J.-B.; Nolan, S.
P.; Gladysz, J. A. J. Am. Chem. Soc. 2002, 124, 1516–1523;
(b) Bhattacharyya, P.; Croxtall, B.; Fawcett, J.; Fawcett,
J.; Gudmunsen, D.; Hope, E. G.; Kemmitt, R. D. W.;
Paige, D. R.; Russell, D. R.; Stuart, A. M.; Wood, D. R.
W. J. Fluorine Chem. 2000, 101, 247–255; (c) Stibrany, R.;
Gorun, S. M. J. Organomet. Chem. 1999, 579, 217–221.
10. (a) Benefice-Malouet, S.; Blancou, H.; Commeyras, A. J.
Fluorine Chem. 1985, 30, 171–187; (b) Langer, F.;
In conclusion, a new synthetic protocol was developed
for the synthesis of fluorous tertiary phosphines. Our
procedure offers a safer approach byavoiding the use
Puntener, K.; Sturmer, R.; Knochel, P. Tetrahedron:
¨
¨
Asymmetry 1997, 8, 715–738; (c) Bhattacharyya, P.;
Gudmunsen, D.; Hope, E. G.; Kemmitt, R. D. W.; Paige,
D. R.; Stuart, A. M. J. Chem. Soc., Perkin Trans. 1 1997,
3609–3612.
of the highlytoxic and hazardous PH . Furthermore,
3
the synthetic protocol allows variation of the number
of methylene spacers and the length of the fluorous
ponytails providing a library of fluorous tertiary phos-
phines with fine tuning of the basicityof the phosphorus
atom and the partition coefficients of the phosphines or
their transition metal complexes.
´
´
11. Vlad, G.; Richter, F.; Horvath, I. T. Org. Lett. 2004, 6,
4559–4561.
12. Freedman, L. D.; Doak, G. O. J. Am. Chem. Soc. 1952,
74, 3414–3415.
13. General procedure for the radical additions of fluorous
olefins to phenylphosphine: A 20 mL Fischer–Porter
bottle was charged with the appropriate fluorous olefin
(18.25 mmol, 25% excess), PhPH2 (7.30 mmol), and AIBN
(100 mg, 8 mol %) under nitrogen. The bottle was closed
and the biphasic mixture was stirred at 78–80 ꢁC for 2 h.
AIBN (100 mg) was added after every2 h (four times),
and finallythe homogeneous mixture was stirred for 7 h.
The resulting slightlyyellow oil/solid was placed under
vacuum (0.05 mbar) at 80 ꢁC in order to remove the excess
fluorous olefin and the tetramethyl-succinonitrile giving
the corresponding bis(perfluoroalkyl-alkyl)phenylphos-
phine. This phosphine could be recrystallized from iso-
octane at low temperature, if needed.
Acknowledgements
This work was supported bythe Hungarian National
Scientific Research Fund (OTKAT032850). We are
´
´
pleased to acknowledge Professor Jozsef Rabai for pro-
viding samples of the 3-perfluoroalkyl-1-propenes. We
thank Ute Hoffmann and Andreas Hecking at Bayer
Material Science AG for their kind help.
14. General procedure for the alkylation of fluorous phenyl-
phosphine derivatives: The appropriate bis(perfluoroalkyl-
alkyl)phenylphosphine (6.80 mmol) and perfluoroalkyl-
alkyl iodide (13.6 mmol, 100% excess) were placed in a
20 mL heavy-walled vial under nitrogen. The vial was
closed and the mixture was stirred at 140 ꢁC for 16 h.
After cooling to room temperature, 40 mL of FC-72 or
CH2Cl2 was added to the yellowish solid, the mixture was
finelypowdered in a mortar, and filtered through a
Supplementary data
Supplementarydata containing the NMR data of the
compounds is available. Supplementarydata associated
with this article can be found, in the online version, at
Buchner funnel. Washing with 2 · 10 mL of FC-72 and
¨
References and notes
drying in vacuo resulted in the corresponding phospho-
nium salt as a white or slightlyyellow powder.
´
´
1. (a) Horvath, I. T.; Rabai, J. Science 1994, 266, 72–75; (b)
15. Fenton, G. W.; Ingold, C. K. J. Chem. Soc. 1929, 2342–
2357.
´
Gladysz, J. A.; Curran, D. P.; Horvath, I. T. Handbook of
Fluorous Chemistry; Wiley/VCH: Weinheim, 2004.
2. Wende, M.; Gladysz, J. A. J. Am. Chem. Soc. 2003, 125,
5861–5872.
3. Horvath, I. T. Acc. Chem. Res. 1998, 31, 641–650.
4. Horvath, I. T.; Kiss, G.; Cook, R. A.; Bond, J. E.; Stevens,
P. A.; Rabai, J.; Mozeleski, E. J. J. Am. Chem. Soc. 1998,
120, 3133–3143.
5. Dalko, P. I.; Moisan, L. Angew. Chem., Int. Ed. 2004, 43,
5138–5175.
6. (a) Parshall, G. W.; England, D. C.; Lindsey, R. V., Jr. J.
Am. Chem. Soc. 1959, 81, 4801–4802; (b) LavrentÕev, A.
N.; Maslennikov, I. G.; Sochilin, E. G. Zh. Obshch. Khim.
1973, 43, 2663–2665; (c) Gopal, H.; Snyder, C. E., Jr.;
Tamborski, C. J. Fluorine Chem. 1979, 14, 511–518; (d)
Nixon, J. F. Adv. Inorg. Chem. Radiochem. 1985, 29, 41–
16. General procedure for the dephenylation of phosphonium
salts: The appropriate phosphonium salt (4.33 mmol) was
placed into a heavy-walled round-bottomed flask and
treated with NaOH (17.3 mmol) and with 1:3 mixture of 2-
propanol/water (9 mL). The flask was closed and heated
to 120 ꢁC with vigorous stirring. After 12 h the reaction
mixture was cooled to room temperature and treated with
FC-72 (40 mL) and water (30 mL). The biphasic mixture
was stirred for 2 min, the fluorous phase was filtered
through a layer of MgSO4, and evaporated in vacuo to
give the corresponding phosphine oxide as a white
powder. For further purification, the solid could be
´
´
´
recrystallized
from
perfluoro-2-butyl-tetrahydro-
furan. According to its low solubilityin FC-72,