The addition of F113 and CFCl2CF2CFCl2 to alkenes promoted by sodium dithionite

Article abstract of DOI:10.1016/S0022-1139(98)00246-2

The addition of F113 and CFCl₂CF₂CFCl₂ to alkenes promoted by sodium dithionite occurs to give the corresponding fluoroalkylation products in moderate yields.

Full text of DOI:10.1016/S0022-1139(98)00246-2

Journal of Fluorine Chemistry 92 (1998) 85±87
The addition of F113 and CFCl2CF2CFCl2 to
alkenes promoted by sodium dithionite
Fan-Hong Wu1, Wei-Yuan Huang*
Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032, China
Received 14 April 1998; accepted 14 July 1998
Abstract
The addition of F113 and CFCl2CF2CFCl2 to alkenes promoted by sodium dithionite occurs to give the corresponding ¯uoroalkylation
products in moderate yields. # 1998 Elsevier Science S.A. All rights reserved.
Keywords: F113; CFCl2CF2CFCl2; Sodium dithionite; Fluoroalkylation
1. Introduction
product, a tetrahydrofuran derivative 3 as the major product.
Further results are summarized in Table 1.
Poly¯uoroalkylation initiated by sul®natodehalogenation
reagents, such as sodium dithionite, Rongalite, sodium
bisul®te was studied in our laboratory in recent years
[1,2]. Poly¯uoroalkyl halides containing groups, such as
CF2I, CF2Br, CCl3, could undergo the poly¯uoroalkylation
reaction in the presence of the sul®nato-dehalogenation
reagents [3±7]. Due to the high chemical stability of
F113, there have been only a few reports on its reaction
[8,9]. Herein we wish to present the addition reaction of
F113 and CFCl2CF2CFCl2 with alkenes initiated by sodium
dithionite.
The reaction was considered to proceed through poly-
¯uoroalkyl radical intermediate. Only the hydropoly¯uoro-
alkylation product was formed apparently due to the high
bond energy of carbon±chlorine bond. Thus
CF2ClCFCl2 ‡ SOꢀ ! CF2ClCFClꢀ ‡ SO2 ‡ Cl
2
CF2ClCFClꢀ ‡ CH2ˆCHR ! CF2ClCFClCH2CHRꢀ
H abstraction
In aqueous acetonitrile solution, F113 reacted with
alkenes and 1-hexyne at 40±508C for 12 h to give the
corresponding poly¯uoro-alkylation products in moderate
yields. For example,
!
CF2ClCFClCH2CH2R
CF2ClCFCl2 ‡ CH2ˆCHꢁCH2†3CH3 ! CF2ClCFClꢁCH2†5CH3
1
ˆ
CF2ClCFCl2 ‡ CH CꢁCH2†3CH3 ! CF2ClCFClCHˆCHꢁCH2†3CH3
2 ꢁE=Z†
Under similar conditions, CFCl2CF2CFCl2 reacted with
diallyl ether to give the corresponding addition-cyclization
2. Experimental
All boiling and melting points were uncorrected. IR
spectra were recorded on IR-440 spectrometer using ®lm
or potassium bromide pellet. 19F NMR spectra were
recorded on a Varian EM-360L (56.4 MHz) or FX-90Q
(84.6 MHz) spectrometers in carbon tetrachloride, CDCl3
or d6-acetone using TFA as external standard. Chemical
*Corresponding author. Tel.: +86-21-64163300; fax: +86-21-64166128;
e-mail: wyhuang@pub.sioc.ac.cn
1Present address: Department of Organic Chemistry, Institute of
Fundamental Education, East China University of Science and Technol-
ogy, Shanghai 200237, China.
0022-1139/98/$ ± see front matter # 1998 Elsevier Science S.A. All rights reserved.
P I I : S 0 0 2 2 - 1 1 3 9 ( 9 8 ) 0 0 2 4 6 - 2

86
F.-H. Wu, W.-Y. Huang / Journal of Fluorine Chemistry 92 (1998) 85±87
Table 1
The adducts of F113, CFCl2CF2CFCl2 with alkenes
shifts in ppm were positive for up®eld shifts (ꢀCFCl
ˆ
crude product was puri®ed over silica gel to give the adduct
1 in yield of 56% [9].
3
ꢀTFA‡76.8 ppm). 1H NMR spectra were recorded on
an EM-360A (60 MHz) spectrometer in carbon tetra-
chloride, CDCl3 or d6-acetone using TMS as external or
internal standard, or obtained on a FX-90Q (90 MHz),
Varian XL-200 (200 MHz) or Bruker AC-300 (300 MHz)
spectrometers in CDCl3 or d6-acetone. MS spectra were
obtained on a Finnigan GC-MS-4021 spectrometer and a
Finnigan-8430 for high resolution mass spectra (HRMS).
Elemental analysis data were obtained by the elemental
analysis group of Shanghai Institute of Organic Chemistry.
The column chromatography was performed by using
silica gel H with petroleum ether and ethyl acetate as
the eluent.
(1): ꢀH (CCl4): 0.90 (3H, t, CH3), 2.30(2H, m, CH2CFCl),
1.30±2.20 (8H, m, other hydrogen atoms) ppm. ꢀF (CCl4):
66.8 (2F, s, CF2Cl), 118.8 (1F, m, CFCl) ppm.
(2): ꢀH (CCl4): 0.90 (3H, t, CH3), 1.35 (4H, m, 2ÂCH2),
2.30 (2H, m, CH2), 5.60, 6.40 (2H, m, CH=CH)ppm. ꢀF
(CCl4): 66.8 (2F,s, CF2Cl), 118.4, 121.2 (E/Z, 1F, m, CFCl)
ppm [9].
(3): ꢀH (CDCl3): 0.90 (3H, t, CH3), 4.0 (m), 3.50 (m),
1.70±2.90 (m) ppm. ꢀF (CCl4): 65.8 (1F, s, CFCl2), 109.8
(2F, s, CF2), 114.8 (1F, m, CFCl) ppm. m/z (%): 321 (2.34),
‡
320 (1.19), 319 (8.26), 318 (2.32), 317 (11.24), 316 (M ,
1.79), 288 (7.82), 286(7.96),99 (6.74), 90 (16.36), 69 (100),
55 (17.99).
(4): ꢀH (CCl4): 0.90 (3H, t, CH3), 2.30 (2H, m, CH2CFCl),
1.30±2.20 (12H, m, other hydrogen atoms) ppm. ꢀF (CCl4):
66.8 (1F, s, CFCl2), 109.8 (2F, s, CF2), 114.8 (1F, m, CFCl)
3. Typical procedure:
‡
The mixture of F113 (3.75 g, 20 mmol), 1-hexene
(0.84 g, 10 mmoL), sodium dithionite (4 g), sodium bicar-
bonate (2 g), acetonitrile (30 ml) and water (10 ml) was
stirred at 40±458C for 20 h. 60 ml water was added to
dissolve the solid. The mixture was extracted by ether.
The combined organic layer was washed with saturated
aqueous sodium chloride solution, and dried over anhydrous
sodium sulfate. After removal of the organic solvent, the
ppm. m/z (%): 311 (2.66), 330(M ), 287 (7.45), 211 (21.71),
141 (11.14), 111 (15.34), 97 (20.66), 85 (49.48), 71 (65.11),
69 (32.84), 57 (100), 43 (70.05). Anal. Calc. for
C11H17Cl3F4 (MW 331.5) C 39.82 H 5.13 F 22.93. Found:
C 40.00 H 5.42 F 23.10
(5): ꢀH (CCl4): 3.50 (1H, m, CHCFCl), 1.20±2.50 (10H,
m, other hydrogen atoms) ppm. ꢀF (CCl4): 61.8 (2F, s,
CF2Cl), 116.8 (1F, m, CFCl) ppm [9].

F.-H. Wu, W.-Y. Huang / Journal of Fluorine Chemistry 92 (1998) 85±87
87
[2] Fan-Hong Wu, Bing-Nan Huang, Wei-Yuan Huang, Youji Huaxue 13
(1993) 449.
(6): ꢀH (CCl4): 1.90 (2H, m, CH2), 2.30 (2H, m,
CH2CFCl), 3.55 (2H, t, CH2OH), 3.90 (1H, s, OH) ppm.
ꢀF (CCl4): 65.8 (2F, s, CF2Cl), 119.0 (1F, m, CFCl) ppm [9].
(7): ꢀH (CCl4): 1.33 (3H, m, CH3), 2.30±3.0 (4H, m), 3.70
(2H, m, CH2), 4.20 (2H, m, CH2) ppm. ꢀF (CCl4): 66.6 (2F,
s, CF2Cl), 118.8 (1F, m, CFCl) ppm [9].
[3] Bing-Nan Huang, Wei-Yuan Huang, Chang-Ming Hu, Acta Chim.
Sinica 39 (1981) 481.
[4] W.Y. Huang, B.N. Huang, C.M. Hu, J. Fluor. Chem. 23 (1983) 193.
[5] Wei-Yuan Huang, Bing-Nan Huang, Jian-Long Chen, Acta Chim.
Sinica 44 (1986) 45.
[6] Wei-Yuan Huang, Bing-Nan Huang, Jian-Long Chen, Acta Chim.
Sinica 43 (1985) 1167.
[7] Fan-Hong Wu, Bing-Nan Huang, Long Lu, Wei-Yuan Huang, J.
Fluor. Chem. 80 (1996) 91.
References
[8] D.J. Burton, L.T. Kehoe, J. Org. Chem. 35 (1970) 1339.
[9] C.M. Hu, F.L. Qing, Tetrahedron Lett. 31 (1990) 1307.
[1] Fan-Hong Wu, Wei-Yuan Huang, Youji Huaxue 17 (1997) 106.