The chemistry of tetrafluoroallene: Nucleophilic addition reactions with phenols and amines

Article abstract of DOI:10.1016/S0022-1139(03)00133-7

Treatment of tetrafluoroallene or its precursor, ICF₂ CH₂CF₂I, with phenols in the presence of K₂CO₃ gave the corresponding unsaturated ethers. Tetrafluoroallene also reacted readily with amines in TH

Full text of DOI:10.1016/S0022-1139(03)00133-7

Journal of Fluorine Chemistry 123 (2003) 189–195
The chemistry of tetrafluoroallene: nucleophilic
addition reactions with phenols and amines
Ji-Chang Xiao, Qing-Yun Chen*
Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry,
Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, China
Received 28 February 2003; received in revised form 14 April 2003; accepted 19 April 2003
Abstract
Treatment of tetrafluoroallene or its precursor, ICF2CH2CF2I, with phenols in the presence of K2CO3 gave the corresponding unsaturated
ethers. Tetrafluoroallene also reacted readily with amines in THF at room temperature to afford 3,3,3-trifluoropropionamides.
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Tetrafluoroallene; Nucleophilic addition reactions; Phenol; Amine
1. Introduction
corresponding [2 þ 2]-adducts. Some interesting hetero-
cyclic compounds were also obtained through 1,3-dipolar
cycloaddition of 1 to N-phenylsydone [10], phenylazide [10],
nitrone [11], diazophenylmethane [11] and diazodiphenyl-
methane [11]. Apparently, the chemistry of 1 has not been
significantly developed because of its still difficult prepara-
tion. Recently, we reported that the yield of 1 was greatly
improved by using 1,3-diiodo-1,1,3,3-tetrafluoropropane
(ICF2CH2CF2I, 2) as its precursor which can be smoothly
synthesized by the reaction of CF2I2 with CF2¼CH2 in the
presence of Pb(OAc)4 [12]. Elimination of hydrogen iodide
from 2 with K2CO3 in CH3CN afforded 1 in good yield [12].
Thus, our new synthetic method for 1 makes the possibility
for further expanding the chemistry of 1. For example, very
recently, we found that trifluoromethylindolizines could be
obtained by 1,3-dipolar cycloaddition either from 1 to
pyridinium bromide or from 2 in the presence of K2CO3
in CH3CN at 65 8C [13] (Scheme 2).
It is known that fluoroallene and 1,1-difluoroallene, as
allene derivatives, are prone to cycloaddition to alkenes [1],
dienes [1a,2], nitrone [3] and diazo compounds [4] to give a
quite variety of useful compounds. However, their analog,
tetrafluoroallene (1), was less investigated. In 1959 Jacobs
and Bauer first reported the synthesis of 1 by three-step
procedure starting from dibromodifluoromethane [5] as
shown follows (Scheme 1).
They also studied the chlorination [5] and dimerization
[5] of 1. After certain modification of the procedure, Banks
et al. carried the ionic reaction of 1 with hydrogen halides,
HX (X ¼ Br, Cl, F) and fluoride ion to give XCF2CH¼CF2
and CF3CH¼CF2, respectively [6]. Fluoroallene 1 readily
dimerizes to perfluoro-(1,2-dimethylenecyclobutane) and
homopolymerized to [–C(¼CF2)CF2–]n [5–7]. The cycload-
dition of 1 to CF3NO [8] or CF3CBCCF3 [9] gives the
Herein, we present the results of nucleophilic additions of
phenols and amines to 1.
2. Results and discussion
Although it was reported that 1 reacted with H2O, MeOH
and MeSH to give the corresponding X–CF2CH¼CF2
(X ¼ OH, OMe, SMe) [10], the experimental data of these
compounds in detail were not available. We found that
treatment of 2 with phenol (3a) in the presence of K2CO3
(10 mmol) in CH3CN at 65 8C for 8 h gave the phenyl ether
Scheme 1.
* Corresponding author. Tel.: þ86-21-64163300;
fax: þ86-21-64166128.
E-mail address: chenqy@pub.sioc.ac.cn (Q.-Y. Chen).
0022-1139/$ – see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0022-1139(03)00133-7

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J.-C. Xiao, Q.-Y. Chen / Journal of Fluorine Chemistry 123 (2003) 189–195
Scheme 2.
Scheme 4.
Scheme 3.
Scheme 5.
4a in high yield. The control experiment, i.e. using 1 as a
reactant instead of 2 in the presence of catalytic amount of
K2CO3 at room temperature for 6 h afforded the same
product with a comparable yield. The absence of K2CO3
did not initiate the reaction showing that phenol is not a good
nucleophile towards 1 (Scheme 3).
Similarly, several aromatic ethers were obtained either by
the reactions of 2 with substituted phenols (one-pot proce-
dure) or by that of 1 (two-step procedure) in comparable
high yields (Scheme 4).
The results are listed in Table 1.
Amines, different from phenols, reacted with 2 sluggishly
in one pot, the products being very complicated. However,
mixing 1 and benzyamine (5a) in THF at room temperature
quickly gave the unexpected b,b,b-trifluoropropionamide
(6a) (Scheme 5). The structure for 6a was established by
its spectral data (IR, MS, NMR) and elemental analysis as
well as X-ray diffraction. (Fig. 1).
Scheme 6.
Fig. 1. The X-ray structure of compound 6a.

J.-C. Xiao, Q.-Y. Chen / Journal of Fluorine Chemistry 123 (2003) 189–195
191
Table 1
Reaction of 2 or 1 with ArOH (3)
Entry
Substrate
Product
Yielda (%)
One-potb
Two-stepc
1
2
90
92
93
91
3
85
88
4
5
6
88
83
80
90
85
87
7
91
95
8
9
90
93
95
92
10
87
9
11
12
84
93
93
95
a Isolated yields based on phenols used.
b 2:ArOH:K2CO3 ¼ 5:3:10 in CH3CN at 65 8C for 10 h.
c 1:ArOH:K2CO3 ¼ 4:3:0.3 in CH3CN at room temperature for 8 h.
Based on the presence of fluoride ion in aqueous layer
after workup of the reaction mixture, we proposed that
amine was not only used as a reactant but also as a
dehydrofluorination reagent, thus the base was unnecessary
for the reaction (Scheme 6).
Substituted benzylamines (5a–g, 5i and 5j) and simple
aliphatic amine (5h) underwent a similar reaction with 1
(Scheme 7).
3. Experimental
Melting points were recorded at atmospheric pressure and
were uncorrected. 1H NMR and 19F NMR spectra were
recorded on a Varian-360L instrument or Bruker AM-300
spectrometer for solution in CDCl3 with TMS and CFCl3 as
the internal and external standards respectively, and the
upfields are negative. Coupling constants are given in Hz.
IR spectra were obtained with a Perkin-Elmer 983G spectro-
photometer. Lower resolution mass spectra (LRMS) and
higher resolution mass spectra (HRMS) were obtained on
a HP-5989a and Finnigan MAT-8430 instruments, respec-
tively. Organic solvents were dried by standard methods
The results are listed in Table 2.
In conclusion, we provided several examples of the
nucleophilic addition reactions of phenols and amines to
tetrafluoroallene. The studies on the electrophilic and free
radical reactions of 1 are in progress.

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J.-C. Xiao, Q.-Y. Chen / Journal of Fluorine Chemistry 123 (2003) 189–195
Scheme 7.
when necessary. All the commercially available reagents
were of analytical grade and were used without further
purification. Flash column chromatography was carried
out using 300–400 mesh silica gel.
and anhydrous acetonitrile (3 ml). After addition of K2CO3
(10 mmol, 1.38 g), the tube was immediately sealed and then
heatedinanoilbathat65 8Cfor8 h.Cooledthetubetoꢀ50 8C
for 5 min, opened it and then warmed again to room tempera-
ture. The mixture was poured into H2O (40 ml) and extracted
with Et2O 3 ml ꢁ 15 ml). Then the combined organic layer
was washed with brine (3 ml ꢁ 20 ml). The organic layer
was dried over anhydrous sodium sulfate. The solvent was
removed under reduced pressure and the crude product was
purified by flash column chromatography to give the product.
3.1. General procedure for the preparation of
unsaturated polyfluoroaryl ethers
Procedure A. One-pot method: A 6 ml Pyrex tube was
placed ICF2CH2CF2I (2) (5 mmol, 1.84 g), phenol (3 mmol)
Table 2
The results of 1 with aminesa
Entry
Substrate
Product
Yieldb (%)
1
2
62
57
3
4
5
59
52
58
6
55
7
8
9
53
46
60
10
51
a 1:RNH2 ¼ 4:3 at room temperature for 4 h.
b Based on amine.

J.-C. Xiao, Q.-Y. Chen / Journal of Fluorine Chemistry 123 (2003) 189–195
193
Procedure B. Two-step method: Tetrafluoroallene (1) was
prepared according to [12]. Into a 6 ml Pyrex tube contain-
ing phenol (3 mmol), K2CO3 (4 mmol, 0.553 g), anhydrous
CH3CN (3 ml) was condensed CF2¼C¼CF2 (1) (0.448 g,
4 mmol). The tube was sealed and allowed to warm to room
temperature and then stirred for 6 h. The subsequent opera-
tion was the same as procedure A.
CH), 2.33 (s, 3H, CH3). 19F NMR (CDCl3, CFCl3) d (ppm):
ꢀ60.6 (m, 2F), ꢀ73.4 (m, 1F), ꢀ78.9 (m, 1F). IR (nmax
(cmꢀ1)): 1724(vs), 1508(vs), 1382(vs), 1272(m), 1228(vs),
1194(vs), 1123(vs), 1102(vs), 978(s). MS (EI) m/z (relative
intensity): 220 (Mþ, 25), 201 (2), 113 (89), 108 (45), 91
(100), 77 (26). HRMS (EI) Calcd. for C10H8F4O 220.0510;
Found: 220.0482.
3.1.1. 3-Phenoxy-1,1,3,3-tetrafluoro-1-propene (4a)
Colorless liquid: 1H NMR (CDCl3, Me4Si) d (ppm): 7.18–
7.39 (m, 5H, ArH), 4.88 (dtd, J ¼ 22:3, 7.2, 1.9 Hz, 1H,
CH). 19F NMR (CDCl3, CFCl3) d (ppm): ꢀ60.5 (m, 2F),
ꢀ73.2 (m, 1F), ꢀ78.7 (m, 1F). IR (nmax (cmꢀ1)): 1660(w),
1633(m), 1468(m), 1260(m), 1093(m), 1016(s), 798(m). MS
(EI) m/z (relative intensity): 206 (Mþ, 23), 187 (1), 113
(100), 94 (17), 77 (12), 69 (6). HRMS (EI) Calcd. for
C9H6F4O 206.0353; Found: 206.0365.
3.1.6. 3-(2-Methylphenoxy)-1,1,3,3-tetrafluoro-
1-propene (4f)
Colorless liquid: 1H NMR (CDCl3, Me4Si) d (ppm): 7.12–
7.25 (m, 4H, ArH), 4.90 (dtd, J ¼ 22:4, 6.7, 1.8 Hz, 1H,
CH), 2.27 (s, 3H, CH3). 19F NMR (CDCl3, CFCl3) d (ppm):
ꢀ60.0 (m, 2F), ꢀ73.2 (m, 1F), ꢀ78.9 (m, 1F). IR (nmax
(cmꢀ1)): 1764(m), 1722(vs), 1588(m), 1493(s), 1385(vs),
1274(s), 1222(vs), 1174(vs), 1116(vs), 1098(vs), 979(s). MS
(EI) m/z (relative intensity): 220 (Mþ, 1), 201 (44), 181 (5),
108 (10), 91 (100), 77 (18). HRMS (EI) Calcd. for C10H8F4O
220.0510; Found: 220.0462.
3.1.2. 3-(4-Chlorophenoxy)-1,1,3,3-tetrafluoro-
1-propene (4b)
Colorless liquid: 1H NMR (CDCl3, Me4Si) d (ppm): 7.11–
7.35 (m, 4H, ArH), 4.87 (dtd, J ¼ 22:4, 7.0, 1.6 Hz, 1H, CH).
19F NMR (CDCl3, CFCl3) d (ppm): ꢀ61.5 (m, 2F), ꢀ72.8 (m,
1F), ꢀ78.3 (m, 1F). IR (nmax (cmꢀ1)): 1726(vs), 1489(vs),
1375(s), 1235(s), 1165(m), 1105(vs), 976(m). MS (EI) m/z
(relative intensity): 240 (Mþ, 37), 221 (2), 193 (2), 149 (3),
128 (11), 113 (100), 75 (6). Anal. Calcd. for C9H5ClF4O: C
44.93, H 2.09, F 31.59; Found: C 44.92, H 2.11, F 31.58.
3.1.7. 3-(1-Naphthoxy)-1,1,3,3-tetrafluoro-1-propene (4g)
Colorless liquid: 1H NMR (CDCl3, Me4Si) d (ppm): 7.38–
8.12 (m, 7H, ArH), 4.99 (dtd, J ¼ 22:3, 7.1, 2.0 Hz, 1H,
CH). 19F NMR (CDCl3, CFCl3) d (ppm): ꢀ60.1 (m, 2F),
ꢀ72.8 (m, 1F), ꢀ78.3 (m, 1F). IR (nmax (cmꢀ1)): 3064(w),
1720(vs), 1601(m), 1510(m), 1390(s), 1234(vs), 1222(vs),
1111(vs), 1078(s), 961(m), 773(s). MS (EI) m/z (relative
intensity): 256 (Mþ, 58), 237 (1), 144 (71), 115 (100), 113
(83), 89 (12). Anal. Calcd. for C13H8F4O: C 60.95, H 3.15, F
29.66; Found: C 60.84, H 3.28, F 29.38.
3.1.3. 3-(2-Bromophenoxy)-1,1,3,3-tetrafluoro-
1-propene (4c)
Colorless liquid: 1H NMR (CDCl3, Me4Si) d (ppm): 7.10–
7.64 (m, 4H, ArH), 4.95 (dtd, J ¼ 22:5, 7.6, 2.2 Hz, 1H, CH).
19F NMR (CDCl3, CFCl3) d (ppm): ꢀ60.6 (m, 2F), ꢀ72.2 (m,
1F), ꢀ77.9 (m, 1F). IR (nmax (cmꢀ1)): 1724(vs), 1475(s),
1376(vs), 1234(s), 1213(s), 1106(s), 1050(m), 978(m). MS
(EI) m/z (relative intensity): 284 (Mþ, 5), 220 (10), 194 (8),
113 (100), 108 (17). Anal. Calcd. for C9H5BrF4O: C 37.92, H
1.77, F 26.66; Found: C 37.62, H 1.75, F 26.52.
3.1.8. 3-(2-Naphthoxy)-1,1,3,3-tetrafluoro-1-propene (4h)
Colorless liquid: 1H NMR (CDCl3, Me4Si) d (ppm): 7.31–
7.85 (m, 7H, ArH), 4.93 (dtd, J ¼ 22:3, 7.0, 1.8 Hz, 1H, CH).
19F NMR (CDCl3, CFCl3) d (ppm): ꢀ60.4 (m, 2F), ꢀ73.0 (m,
1F), ꢀ78.5 (m, 1F). IR (nmax (cmꢀ1)): 3066(w), 1724(vs),
1600(m), 1391(s), 1240(vs), 1209(s), 1158(s), 1119(vs),
1104(vs), 990(vs). MS (EI) m/z (relative intensity): 256
(Mþ, 100), 144 (74), 113 (46). Anal. Calcd. for C13H8F4O:
C 60.95, H 3.15, F 29.66; Found: C 60.92, H 3.12, F 29.37.
3.1.4. 3-(3-Methoxyphenoxy)-1,1,3,3-tetrafluoro-
1-propene (4d)
3.1.9. 4-(1,1,3,3-Tetrafluoroallyloxy)benzaldehyde (4i)
Colorless liquid: 1H NMR (CDCl3, Me4Si) d (ppm): 9.99
(s, 1H, CHO), 7.30–8.14 (m, 4H, ArH), 4.93 (dtd, J ¼ 22:2,
7.3, 2.0 Hz, 1H, CH). 19F NMR (CDCl3, CFCl3) d (ppm):
ꢀ61.5 (m, 2F), ꢀ72.3 (m, 1F), ꢀ77.7 (m, 1F). IR (nmax
(cmꢀ1)): 3087(m), 1757(vs), 1705(s), 1604(s), 1373(s),
1289(m), 1211(s), 1113(vs), 1052(vs), 960(vs). MS (EI)
m/z (relative intensity): 234 (Mþ, 10), 121 (6), 113 (100),
105 (1). Anal. Calcd. for C10H6F4O2: C 51.30, H 2.58, F
32.46; Found: C 51.13, H 2.69, F 32.12.
Colorless liquid: 1H NMR (CDCl3, Me4Si) d (ppm): 6.79–
7.33 (m, 4H, ArH), 4.92 (dtd, J ¼ 22:2, 7.0, 1.6 Hz, 1H,
CH), 3.85 (s, 3H, CH3). 19F NMR (CDCl3, CFCl3) d (ppm):
ꢀ60.6 (m, 2F), ꢀ73.3 (m, 1F), ꢀ78.8 (m, 1F). IR (nmax
(cmꢀ1)): 1722(vs), 1614(s), 1493(vs), 1382(s), 1267(s),
1228(vs), 1140(vs), 1101(vs), 991(m). MS (EI) m/z (relative
intensity): 236 (Mþ, 30), 217 (1), 124 (44), 113 (100), 107
(6), 95 (9). Anal. Calcd. for C10H8F4O2: C 50.86, H 3.41, F
32.18; Found: C 50.73, H 3.39, F 31.90.
3.1.5. 3-(4-Methylphenoxy)-1,1,3,3-tetrafluoro-
1-propene (4e)
Colorless liquid: 1H NMR (CDCl3, Me4Si) d (ppm): 7.05–
7.24 (m, 4H, ArH), 4.85 (dtd, J ¼ 22:2, 7.0, 1.9 Hz, 1H,
3.1.10. 3-(8-Quinolyloxy)-1,1,3,3-tetrafluoro-
1-propene (4j)
Yellow liquid: H NMR (CDCl3, Me4Si) d (ppm): 9.01
(m, 1H, ArH), 7.44–8.20 (m, 5H, ArH), 5.13 (dtd, J ¼ 22:3,
1

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8.3, 1.9 Hz, 1H, CH). 19F NMR (CDCl3, CFCl3) d (ppm):
ꢀ60.9 (m, 2F), ꢀ73.0 (m, 1F), ꢀ78.2 (m, 1F). IR (nmax
(cmꢀ1)): 3071(w), 1758(vs), 1502(s), 1371(vs), 1221(s),
1126(vs), 1048(s), 958(s), 796(m). MS (EI) m/z (relative
intensity): 257 (Mþ, 3), 238 (8), 191 (96), 159 (53), 145
(100), 113 (59), 89 (43). Anal. Calcd. for C12H7F4NO: C
56.04, H 2.74, N 5.45, F 29.55; Found: C 56.08, H 2.79, N
5.61, F 29.44.
1234(s), 1139(s), 1106(s), 698(m). MS (EI) m/z (relative
intensity): 217 (Mþ, 100), 148 (8), 106 (57), 91 (68). Anal.
Calcd. for C10H10F3NO: C 55.30, H 4.64, N 6.45, F 26.24;
Found: C 55.38, H 4.62, N 6.34, F 26.36.
3.2.2. N-(2-Phenylethyl)-3,3,3-trifluoropropionamide (6b)
1
White solid: mp 76–78 8C. H NMR (CDCl3, Me4Si) d
(ppm): 7.18–7.36 (m, 5H, ArH), 5.72 (br., 1H, NH), 3.58 (q,
J ¼ 6:6 Hz, 2H, NCH2), 3.02 (q, J ¼ 10:8 Hz, 2H, CF3CH2),
2.85 (t, J ¼ 6:7 Hz, 2H, ArCH2). 19F NMR (CDCl3, CFCl3) d
(ppm): ꢀ63.0 (t, J ¼ 10:5 Hz, CF3). IR (KBr) (nmax (cmꢀ1)):
3308(s), 1658(vs), 1562(s), 1393(m), 1364(m), 1261(s),
1240(s), 1157(s), 1109(s), 699(s). MS (EI) m/z (relative
intensity): 231 (Mþ, 6), 111 (11), 104 (100), 91 (31), 69
(2). Anal. Calcd. for C11H12F3NO: C 57.14, H 5.23, N 6.05, F
24.65; Found: C 56.82, H 4.85, N 5.92, F 24.86.
3.1.11. 3-(3-Fluorophenoxy)-1,1,3,3-tetrafluoro-
1-propene (4k)
Colorless liquid: 1H NMR (CDCl3, Me4Si) d (ppm): 6.93–
7.33 (m, 4H, ArH), 4.88 (dtd, J ¼ 22:4, 7.1, 1.7 Hz, 1H,
CH). 19F NMR (CDCl3, CFCl3) d (ppm): ꢀ61.1 (m, 2F),
ꢀ72.3 (m, 1F), ꢀ78.1 (m, 1F), ꢀ111.2 (m, 1F, ArF). IR (nmax
(cmꢀ1)): 1759(vs), 1607(s), 1490(s), 1376(s), 1294(m),
1228(s), 1130(vs), 1056(m), 972(m). MS (EI) m/z (relative
intensity): 224 (Mþ, 13), 205 (1), 113 (100), 95 (9), 69 (11).
HRMS (EI) Calcd. for C9H5F5O 224.0259; Found 224.0239.
3.2.3. N-[2-(4-Bromophenyl)ethyl]-3,3,3-
trifluoropropionamide (6c)
White solid: mp 118–120 8C. 1H NMR (CDCl3, Me4Si) d
(ppm): 7.04–7.45 (m, 4H, ArH), 5.81 (br., 1H, NH), 3.53 (q,
J ¼ 6:5 Hz, 2H, NCH2), 3.02 (q, J ¼ 10:6 Hz, 2H,
CF3CH2), 2.80 (t, J ¼ 6:9 Hz, 2H, ArCH2). 19F NMR
(CDCl3, CFCl3) d (ppm): ꢀ63.4 (t, J ¼ 11:6 Hz, CF3). IR
(KBr) (nmax (cmꢀ1)): 3305(s), 1654(vs), 1568(s), 1489(m),
1403(m), 1276(m), 1240(s), 1141(s), 1109(m). MS (EI) m/z
(relative intensity): 312 (Mþ þ 2, 5), 310 (Mþ, 5), 182 (100),
169 (16), 111 (19), 90 (20), 69 (3). Anal. Calcd. for
C11H11BrF3NO: C 42.60, H 3.58, N 4.52, F 18.38; Found:
C 42.59, H3.31, N 4.34, F 18.35.
3.1.12. 3-[4-(tert-Butyl)phenoxy]-1,1,3,3-tetrafluoro-
1-propene (4l)
Colorless liquid: 1H NMR (CDCl3, Me4Si) d (ppm): 7.11–
7.39 (m, 4H, ArH), 4.89 (dtd, J ¼ 22:4, 7.2, 1.9 Hz, 1H,
CH), 1.33 (s, 9H, C(CH3)3). 19F NMR (CDCl3, CFCl3) d
(ppm): ꢀ60.5 (m, 2F), ꢀ73.3 (m, 1F), ꢀ78.9 (m, 1F). IR
(nmax (cmꢀ1)): 2968(s), 1759(vs), 1512(vs), 1373(vs),
1291(m), 1230(s), 1208(s), 1174(m), 1130(s), 1051(s),
961(vs). MS (EI) m/z (relative intensity): 263 (Mþ þ 1,
14), 247 (93), 135 (74), 113 (34), 105 (100), 77 (38), 57
(27). Anal. Calcd. for C13H14F4O: C 59.54, H 5.38, F 28.98;
Found: C 59.50, H 5.21, F 29.06.
3.2.4. N-[2-(3-Chlorophenyl)ethyl]-3,3,3-
trifluoropropionamide (6d)
1
3.2. General procedure for the reaction of
CF2¼C¼CF2 (1) with amine
White solid: mp 64–66 8C. H NMR (CDCl3, Me4Si) d
(ppm): 7.06–7.28 (m, 4H, ArH), 5.74 (br., 1H, NH), 3.56 (q,
J ¼ 6:6 Hz, 2H, NCH2), 3.03 (q, J ¼ 10:6 Hz, 2H,
CF3CH2), 2.83 (t, J ¼ 7:0 Hz, 2H, ArCH2). 19F NMR
(CDCl3, CFCl3) d (ppm): ꢀ63.0 (t, J ¼ 10:6 Hz, CF3). IR
(KBr) (nmax (cmꢀ1)): 3319(s), 1654(vs), 1558(s), 1394(m),
1365(s), 1266(s), 1235(s), 1141(vs), 1108(s), 797(m). MS
(EI) m/z (relative intensity): 265 (Mþ, 8), 138 (100), 125
(22), 111 (34), 89 (23), 69 (7). Anal. Calcd. for
C11H11ClF3NO: C 49.73, H 4.17, N 5.27, F 21.45; Found:
C 50.01, H 4.06, N 5.25, F 21.45.
Tetrafluoroallene (1) was prepared according to [12]. Into
a 6 ml Pyrex tube containing amine (3 mmol), anhydrous
THF (3 ml) was condensed CF2¼C¼CF2 (1) (0.448 g,
4 mmol). The tube was immediately sealed and allowed
to warm to room temperature and then stirred for 4 h. Cooled
the tube to ꢀ50 8C for 5 min, opened it and then warmed
again to room temperature. The mixture was poured into
H2O (30 ml) and extracted with Et2O (3 ml ꢁ 15 ml). Then
the combined organic layer was washed with brine
(3 ml ꢁ 20 ml). The organic layer was dried over anhydrous
sodium sulfate. The solvent was removed under reduced
pressure and the crude product was purified by flash column
chromatography to give the product.
3.2.5. N-[(4-Methylphenyl)methyl]-3,3,3-
trifluoropropionamide (6e)
White solid: mp 130–132 8C. 1H NMR (CDCl3, Me4Si) d
(ppm): 7.15 (m, 4H, ArH), 5.94 (br., 1H, NH), 4.44 (d,
J ¼ 5:4Hz, 2H, NCH2), 3.09 (q, J ¼ 10:6 Hz, 2H, CF3CH2),
2.34 (s, 3H, CH3). 19F NMR (CDCl3, CFCl3) d (ppm): ꢀ62.9
(t, J ¼ 11:0 Hz, CF3). IR (KBr) (nmax (cmꢀ1)): 3302(s),
1651(vs), 1560(s), 1421(w), 1273(m), 1237(m), 1134(s),
1106(m), 807(m). MS (EI) m/z (relative intensity): 231
(Mþ, 62), 216 (33), 120 (39), 111 (30), 106 (100), 91
(52), 77 (37). Anal. Calcd. for C11H12F3NO: C 57.14, H
3.2.1. N-Benzyl-3,3,3-trifluoropropionamide (6a)
White solid: mp 125–127 8C. 1H NMR (CDCl3, Me4Si) d
(ppm): 7.28–7.36 (m, 5H, ArH), 6.07 (br., 1H, NH), 4.49 (d,
J ¼ 5:4 Hz, 2H, CH2), 3.10 (q, J ¼ 10:6 Hz, 2H, CF3CH2).
19F NMR (CDCl3, CFCl3) d (ppm): ꢀ63.3 (t, J ¼ 11:5 Hz,
CF3). IR (KBr) (nmax (cmꢀ1)): 3314(s), 1645(vs), 1553(s),

J.-C. Xiao, Q.-Y. Chen / Journal of Fluorine Chemistry 123 (2003) 189–195
195
5.23, N 6.05, F 24.65; Found: C 57.14, H 5.30, N 6.00, F
24.26.
(34), 94 (15), 83 (20). HRMS (EI) Calcd. for C10H8BrF4NO
312.9724; Found: 312.9737.
3.2.6. N-[1-(4-Bromophenyl)ethyl]-3,3,3-
3.2.10. N-[(3-Bromo-4-fluorophenyl)methyl]-3,3,3-
trifluoropropionamide (6j)
trifluoropropionamide (6f)
White solid: mp 151–153 8C. 1H NMR (CDCl3, Me4Si) d
(ppm): 7.17–7.51 (m, 4H, ArH), 5.94 (br., 1H, NH), 5.11 (m,
1H, CH), 3.08 (q, J ¼ 10:6 Hz, 2H, CF3CH2), 1.51 (d,
J ¼ 7:1 Hz, 3H, CH3). 19F NMR (CDCl3, CFCl3) d
(ppm): ꢀ62.9 (t, J ¼ 10:9 Hz, CF3). IR (KBr) (nmax
(cmꢀ1)): 3310(s), 1660(vs), 1558(s), 1420(m), 1394(m),
1238(s), 1140(s), 1109(s), 1009(m), 824(m). MS (EI) m/z
(relative intensity): 311 (Mþ þ 1, 36), 309 (Mþ ꢀ 1, 37),
294 (57), 184 (100), 120 (23), 111 (40), 104 (39), 91 (16), 77
(43). Anal. Calcd. for C11H11BrF3NO: C 42.60, H 3.58, N
4.52, F 18.38; Found: C 42.96, H 3.64, N 4.36, F 18.29.
White solid: mp 116–118 8C. 1H NMR (CDCl3, Me4Si) d
(ppm): 7.06–7.48 (m, 3H, ArH), 6.12 (br., 1H, NH), 4.44 (d,
J ¼ 5:7 Hz, 2H, NCH2), 3.12 (q, J ¼ 10:6 Hz, 2H,
CF3CH2). 19F NMR (CDCl3, CFCl3) d (ppm): ꢀ63.3 (t,
J ¼ 10:4 Hz, CF3), ꢀ109.0 (m, 1F, ArF). IR (KBr) (nmax
(cmꢀ1)): 3308(s), 3095(w), 1654(vs), 1563(m) 1498(s),
1392(m), 1266(s), 1243(s), 1150(s), 1112(s), 828(m). MS
(EI) m/z (relative intensity): 315 (Mþ þ 1, 85), 313
(Mþ ꢀ 1, 90), 202 (39), 187 (54), 124 (100), 111 (51),
107 (46), 96 (21), 83 (23). HRMS (EI) Calcd. for
C10H8BrF4NO 312.9724; Found: 312.9740.
3.2.7. N-[(3-Bromophenyl)methyl]-3,3,3-
Acknowledgements
trifluoropropionamide (6g)
White solid: mp 114–116 8C. 1H NMR (CDCl3, Me4Si) d
(ppm): 7.20–7.44 (m, 4H, ArH), 6.08 (br., 1H, NH), 4.46 (d,
J ¼ 5:9 Hz, 2H, NCH2), 3.13 (q, J ¼ 10:6 Hz, 2H,
CF3CH2). 19F NMR (CDCl3, CFCl3) d (ppm): ꢀ63.3 (t,
J ¼ 10:2 Hz, CF3). IR (KBr) (nmax (cmꢀ1)): 3313(s),
1647(vs), 1552(s), 1463(m), 1352(m), 1271(s), 1234(s),
1136(vs), 1110(s), 788(s), 694(m). MS (EI) m/z (relative
intensity): 297 (Mþ þ 1, 53), 295 (Mþ ꢀ 1, 51), 216 (25),
184 (23), 169 (24), 111 (23), 106 (100), 89 (20), 77 (23), 69
(3). Anal. Calcd. for C10H9BrF3NO: C 40.57, H 3.06, N
4.73, F 19.25; Found: C 40.70, H 3.02, N 4.66, F 19.10.
We thank the Chinese National Natural Science Founda-
tion (D20032010, 20272076) for the financial support.
References
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(c) W.R. Dolbier Jr., M.J. Seabury, Tetrahedron Lett. 28 (1987) 1491;
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3.2.8. N-(3-Methylbutyl)-3,3,3-trifluoropropionamide (6h)
1
White solid: mp 39–41 8C. H NMR (CDCl3, Me4Si) d
(b) W.H. Knoth, D.D. Coffman, J. Am. Chem. Soc. 82 (1960) 3872;
(c) A.B. Shtarov, P.J. Krusic, B.E. Smart, W.R. Dolbier Jr., J. Am.
Chem. Soc. 123 (2001) 9956.
(ppm): 5.74 (br., 1H, NH), 3.32 (m, 2H, NCH2), 3.06 (q,
J ¼ 10:6 Hz, 2H, CF3CH2), 1.25–1.66 (m, 3H, CH2CH),
0.92 (d, J ¼ 6:8 Hz, 6H, C(CH3)2). 19F NMR (CDCl3,
CFCl3) d (ppm): ꢀ63.5 (t, J ¼ 11:1 Hz, CF3). IR (KBr)
(nmax (cmꢀ1)): 3301(s), 2962(s), 1649(vs), 1569(s),
1371(m), 1312(m), 1267(s), 1245(s), 1146(s), 1105(s),
930(m). MS (EI) m/z (relative intensity): 197 (Mþ, 1),
182 (4), 154 (34), 141 (100), 128 (21), 111 (32), 91 (9),
70 (35), 55 (43), 44 (50). HRMS (EI) Calcd. for C8H14F3NO
197.1024; Found: 197.1039.
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3.2.9. N-[(5-Bromo-2-fluorophenyl)methyl]-3,3,3-
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Taylor, J. Chem. Soc. (C) (1966) 981–984.
trifluoropropionamide (6i)
White solid: mp 105–107 8C. 1H NMR (CDCl3, Me4Si) d
(ppm): 6.93–7.47 (m, 3H, ArH), 6.17 (br., 1H, NH), 4.50 (d,
J ¼ 5:7 Hz, 2H, NCH2), 3.12 (q, J ¼ 10:6 Hz, 2H,
CF3CH2). 19F NMR (CDCl3, CFCl3) d (ppm): ꢀ63.3 (t,
J ¼ 10:1 Hz, CF3), ꢀ121.4 (m, 1F, ArF). IR (KBr) (nmax
(cmꢀ1)): 3302(s), 3095(w), 1657(vs), 1562(m), 1485(s),
1439(w), 1361(m), 1258(m), 1236(s), 1148(m), 814(m).
MS (EI) m/z (relative intensity): 315 (Mþ þ 1, 60), 313
(Mþ ꢀ 1, 62), 202 (23), 187 (39), 124 (100), 111 (48), 107
[8] R.E. Banks, R.N. Haszeldine, D.R. Taylor, J. Chem. Soc. (1965)
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