1244
LETTERS
SYNLETT
two-step procedure. However, a thionocarboxylate rearrangement23
occurs yielding methyl thioperfluorooctanoate 9, when 4 is heated as a
solution in dipolar aprotic solvents (Scheme 4).24 Compounds 1, 3, 4,
7a, 7b, 8a and 9 were found to be fluorophilic (f > 0, Table 1).
14. Pozzi, G.; Cavazzini, M.; Quici, S.; Fontana, S. Tetrahedron Lett.
1997, 38, 7605.
15. Katritzky, A. R.; Zhang, Z.; Qi, M. Tetrahedron Lett. 1997, 38,
7015.
16. Bissell, E. R.; Finger, M. J. Org. Chem. 1959, 24, 1256.
17. Allouch, M.; Selve, C. J. Fluorine Chem. 1994, 66, 31.
O
C
S
C
100 °C, 1 h
NMP or HMPA
85%
n-C7F15
OCH3
n-C7F15
SCH3
18. Berry, J. S. U.S. Patent 3,194,840 (1965). Chem. Abstr. 1965, 63,
14711g.
4
9
19. To an ice-cold solution of the thioamide (8.0 mmol) and sodium
borohydride (16 mmol) in diglyme (20 mL) borontrifluoride
etherate (25.6 mmol) was added dropwise. Then the mixture was
heated at 110°C for 2 h. The colorless solution was poured into a
mixture of 6N HCl (10 mL) and ice (10 g). The precipitate
(RFCH2NR2.HCl) formed was filtered and partitioned between
ether (2 x 30 mL) and NaHCO3 solution. The ether phase was
dried (MgSO4) and the product isolated by distillation (Table 1).25
Scheme 4
Acknowledgements: This research was supported by the Hungarian
Scientific Research Foundation (OTKA no. T 022169). The authors also
thank Mr. Tibor Ádám for providing UV-Vis spectral data.
References and Notes
20. Olah, G. A.; Welch, J. T.; Vankar, Y. D.; Nojima, M.; Kerekes I.;
1.
a) Aqueous Organometallic Chemistry and Catalysis, NATO ASI
Series, Vol. 5.; Horváth, I. T.; Joó, F., Ed.; Kluwer, Dordrecht,
1995. Aqueous-Phase Organometallic Catalysis; Cornils, B.;
Herrmann, W. A., Ed.; Wiley-VCH, Weinheim, 1998.
Olah, J. A. J. Org. Chem. 1979, 44, 3872.
21. In a polyethylene flask the thioamide (8.7 mmol) was dissolved in
anhydrous dichloromethane (15 mL) at 0 oC. After cautious
addition of PPHF (2 mL) and NBS (34.8 mmol) the mixture was
allowed to warm to room temperature and stirred for 1 h. Then it
was added to saturated aqueous NaHCO3 (20 mL) and followed
by extractive work-up with ether and distillation (Table 1).25
b) Horváth, I. T.; Rábai, J. Science 1994, 266, 72. idem U.S. Patent
5,463,082 (1995); Chem. Abstr. 1995, 123, 87349a. Curran, D. P.
Chemtracts-Org. Chem. 1996, 9, 75. Studer, A.; Hadida, S.;
Ferritto, R.; Kim, S.-Y.; Jeger, P.; Wipf, P.; Curran, D. P. Science
1997, 275, 823. Cornils, B. Angew. Chem., Int. Ed. Engl. 1997, 36,
2057. Curran, D. P. Angew. Chem., Int. Ed. Engl. 1998, 37, 1174.
Horváth, I. T. Acc. Chem. Res. 1998, 31, in press.
22. Yarovenko, N. N.; Raksha, M. A.; Shemanina, V. N.; Vasil’eva,
A.S. Zhur. Obshchei Khim. 1957, 27, 2246.
23. Voss J. In: Supplement B: The Chemistry of Acid Derivatives.
Patai, S., Ed.; Wiley: New York, 1979: pp. 1021-1062.
2.
3.
4.
5.
Kissa, E. Fluorinated Surfactants (Surfactant Science Series, Vol.
50.); Marcel Dekker: New York, 1994.
24. A solution of 4 (5 mmol) in HMPA or NMP (10 mL) was heated at
o
100 C for 1 h. Addition into 6N HCl (10 mL) was followed by
Fluorophilicity (f) values were determined by GC (HP 5890
Series II, PONA ) analysis of the respective phases at equilibrium.
extractive work-up with ether (2 x 20 mL). The combined organic
phases were washed with brine, dried and distilled to isolate
compound 9 (Table 1).25
Boiko, V. N.; Schupak, G. M.; Yagupol’skii, L.M. Zh. Org. Khim.
1977, 13, 1057.
25. Selected spectroscopic and analytical data. The NMR spectra
A solution of 1 (42 mmol) and 2 (40 mmol) in liquid ammonia
(200 mL) was UV-irradiated and refluxed for 40 min using a
‘Tungsram’ HGL 125 lamp. Then the evaporation of ammonia left
a solid residue, which was dissolved in ether (150 mL), washed
with brine (2 x 50 mL), and dried (MgSO4). Compound 3 was
isolated by distillation (Table 1).25
o
were measured in CDCl3 [25 C, δ(ppm), J(Hz)] using TMS and
CFCl3 as the reference for 1H, 13C and 19F nuclei, respectively.
Purity and f values were determined by GC. 3: pale yellow oil,
1
GC: 99%. H: SCH2CH2CO2Et 3.20, t; SCH2CH2CO2Et 2.74, t,
3JHH = 7.2; 13C: SCH2CH2CO2Et 24.0; SCH2CH2CO2Et 35.4;
C(O) 170.9; 19F: CF2S -88.1, tt, 3JFF = 14.6, 5JFF = 2.8; MS m/z
552 [M]+, 133 [SCH2CH2CO2Et]+. 4: yellow-green oil, GC: 98%.
Anal. Calcd. for C9H3F15OS: S 7.22; Found: S 7.06. 1H: OCH3
6.
7.
Rábai, J. Synthesis 1989, 523.
Under an argon atmosphere a suspension of sodium hydride (120
mmol) in ether (300 mL) was treated with 3 (40 mmol) and the
mixture stirred for 30 min at room temperature. After cautious
addition of the mixture to methanol (100 mL) the solvent was
removed in vacuo and followed by extractive work-up with ether.
The combined organic phases were washed successively with 1N
HCl, aqueous NaHCO3, and water, and dried (MgSO4).
Thionoester 4 was isolated by distillation (Table 1).25
5
2
4.27, t, JHF = 0.4; 13C: OCH3 60.2; C(S) 197.0, t, JCF = 29.0;
19F: CF2C(S) -108.7, t, 3JFF = 13.3, 5JFF = 2.9; MS m/z 444 [M]+,
425 [M-F]+, 75 [C(S)OCH3]+. UV-Vis (hexane): λmax 242 nm (ε
7,040). 6a: yellow crystals, m.p. 28 oC, GC: 99.9%. 1H: OCH2
3.77, s, OCH2 3.85, s; NCH2 3.86, s, NCH2 4.37, s; 13C: C(S)
2
182.1, t, JCF = 24.8; O(CH2-)2 52.7, 53.9; N(CH2-)2 66.6, 66.8;
19F: CF2C(S) -97.2, tt, 3JFF = 16.1, 4JFF = 3.8. MS m/z 499 [M]+,
480 [M-F]+, 467 [M-S]+. UV-Vis (hexane): λmax 297 nm (ε
11,990). 6b: yellow crystals, m.p. 48 oC, GC: 99.9%. 1H: CH3
3.47, tt, 5JHF = 2.2, 6JHF = 0.9; CH3 3.52, t, 5JHF = 1.2; 13C: C(S)
182.5, t, 2JCF = 26.2; CH3 43.7, t, JCF = 4.3; 19F: CF2C(S) -98.15,
3JFF = 16.0. MS m/z 457 [M]+, 438 [M-F]+, 413 [RF7C(S)]+, 88
[C(S)N(CH3)2]+. UV-Vis (hexane): λmax 287 nm (ε 11,080). (+)-
6c: yellow-green oil, GC: 97%. 1H: C(S)NHCH(CH3) 8.0;
C(S)NHCH(CH3) 5.67, quint, JNH = 7; C(S)NHCH(CH3) 1.66, d,
3JHH = 6.9; 13C: C(S)NHCH(CH3) 55.0; C(S)NHCH(CH3) 19.5;
C(S)NHCH(CH3) 181.3; 19F: CF2C(S) -110.7. UV-Vis (hexane):
8.
9.
Middleton, W. J.; Howard, E. G.; Sharkey, W. H. J. Org. Chem.
1965, 30, 1375. Middleton, W. J. J. Org. Chem. 1975, 40, 129.
Portella, C.; Shermolovich, Y. G.; Tschenn, O. Bull. Soc. Chim. Fr.
1997, 134, 697.
10. Voss, J.; Walter, W. Liebigs Ann. Chem. 1968, 716, 209.
11. Kuroboshi, M.; Hiyama, T. Tetrahedron Lett. 1994, 35, 3983.
12. Hayashi, T.; Matsumoto, Y.; Morikawa, I.; Ito, Y. Tetrahedron:
Asymmetry 1990, 1, 151.
13. Vincent, J-M.; Rabion, A.; Yachandra, V. K.; Fish, R. H. Angew.
Chem., Int. Ed. Engl. 1997, 36, 2346.
1
λmax 278 nm (ε 11,840). 7a: colorless oil, GC: 98%. H: RFCH2