Fluoroalkylation of aromatic compounds with per(poly)fluoroalkyl chlorides initiated by sodium dithionite in DMSO

Article abstract of DOI:10.1016/S0022-1139(01)00442-0

Treatment of electron-rich aromatic and heteroaromatic compounds with per(poly)fluoroalkyl chlorides in the presence of sodium dithionite in DMSO gives the corresponding fluoroalkylated products in moderate to good yields. The structures and yields of pro

Full text of DOI:10.1016/S0022-1139(01)00442-0

Journal of Fluorine Chemistry 111 ꢀ2001) 107±113
Fluoroalkylation of aromatic compounds with perꢀpoly)¯uoroalkyl
chlorides initiated by sodium dithionite in DMSO
Xiao-Ting Huang, Zheng-Yu Long, Qing-Yun Chen*
Laboratory of Organo¯uorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences,
354 Fenglin Lu, Shanghai 200032, PR China
Received 20 October 2000
Abstract
Treatment of electron-rich aromatic and heteroaromatic compounds with perꢀpoly)¯uoroalkyl chlorides in the presence of sodium
dithionite in DMSO gives the corresponding ¯uoroalkylated products in moderate to good yields. The structures and yields of products
depend mainly on the position and electron-donatingability of the substituents on the aromatic compounds. # 2001 Elsevier Science B.V.
All rights reserved.
Keywords: Perꢀpoly)¯uoroalkyl chlorides; Aromatic; Fluoroalkylation
1. Introduction
2. Results and discussion
Several methods have been reported for direct ¯uoroalk-
ylation of aromatic compounds. Amongthem, there are
copper promoted couplingreactions between per¯uoroalkyl
iodides and aromatic halides [1,2], RuCl2ꢀPh3P)3 catalyzed
[3] or photoinduced [4] reactions of per¯uoroalkanesulfonyl
halides with aromatic halides. The more convenient syn-
thetic method is sul®natodehalogonation, which was dis-
covered and developed by Huang[5]. Usinginexpensive
A mixture of ¯uoroalkyl chlorides, aromatics, Na2S2O4
and NaHCO3 in DMSO was heated to 70±808C. The reac-
tion time was monitored by 19F NMR spectroscopy. Fluor-
oalkylated products, accompanied with a small amount of
RFH ꢀꢀ15%), could be obtained ꢀScheme 1), and the results
are listed in Table 1.
The results in Table 1 show that electron-rich aromatics
can react with RFCl giving the desired products in moderate
to good yields while the electron-poor ones cannot ꢀe.g.
entry 5, Table 1, C6H5NO2) or are very dif®cult ꢀe.g. entry 6,
C6H5CF3). This is consistent with the electrophilic proper-
ties of ¯uoroalkyl radical. The yields and regioselectivity of
the products are determined by the structure of the starting
aromatics. For example, with toluene, N,N-dimethyl aniline
and phenol only o- and p-substituted products were isolated
in 40±60% yields, the yield of RFCl with anisole was
relatively high ꢀ78%), but the regioselectivity was poor,
i.e. besides the o- and p-isomeric products, the m-isomer
ꢀthe ratio of o:p:m ˆ 50:40:10, determined by 19F NMR)
was also detected. When two substituents aꢁre located on the
aromatic ring, the position attacked by RF is mainly gov-
erned by the one of the substituents with stronger electron-
donatingability. For example, in the reaction of 1b with
p-methylanisole, the yield of product with an o-¯uoroalkyl
group relative to OCH3 was 75%, while that relative to CH3
only 25% ꢀentry 12, Table 1). Similarly, a ¯uoroalkyl group
was introduced only into the ortho-position relative to the
sulfur-containingreductants ꢀe.g. Na S2O4) under mild con-
2
ditions perꢀpoly)¯uoroalkyl halides ꢀRFX, where X: Br, I,
CCl3) can either directly ¯uoroalkylate aromatics or afford
®rstly the correspondingsul®nate salts which, then, in the
presence of an oxidant, react with aromatic compounds to
give the same ¯uoroalkylated products. However, this sul®-
natodehalogonation is con®ned to per¯uoroalkyl iodides and
bromides [6±8] and cannot be applied to the per¯uoroalkyl
chlorides. Very recently, we were fortunate to ®nd that using
dimethylsulphoxide ꢀDMSO) as a solvent instead of
CH3CN/H2O, per ꢀpoly)¯uoroalkyl chlorides could be used
as ¯uoroalkylation agents not only for the addition reactions
to alkenes and alkynes [9,10] but also for substitution on
aromatic compounds [11]. This paper presents the more
detailed reaction results of per¯uoroalkyl chlorides with
benzenes and heteroaromatics.
* Correspondingauthor. Fax: ‡86-21-64166158.
E-mail address: chenqy@pub.sioc.ac.cn ꢀQ.-Y. Chen).
0022-1139/01/$ ± see front matter # 2001 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 2 - 1 1 3 9 ꢀ 0 1 ) 0 0 4 4 2 - 0

108
X.-T. Huang et al. / Journal of Fluorine Chemistry 111 12001) 107±113
Scheme 1.
amino group in the reaction of 1b with p-chloroaniline ꢀentry
11, Table 1).
reaction of RFCl with imidazole ꢀentries 2, 7, and 11,
Table 2). However, a small amount ꢀ10%) of 3-¯uoroalkyl
thiophene was also isolated besides the main isomer 2-
¯uoroalkyl thiophene ꢀentries 1, 4, and 5, Table 2) in the
case with thiophene. As expected, ¯uoroalkylation of quino-
line ꢀ5) occurred only on the benzene ringrather than on the
pyridine ringꢀentries 3, and 14, Table 2). In the above
reactions, the ratio of reactants was controlled to be nearly
equivalent, thus the mono-¯uoroalkylated products were
obtained. However, when RFCl was employed in much
excess, bis-¯uoroalkylated aromatics have never been
observed. This may be due to sharp decrease of the elec-
tron-density of the resultant mono-¯uoroalkyl derivatives.
On the other hand, different from the report [16], attempts to
¯uoroalkylate benzene itself met only with failure.
As reported previously, the ethoxycarbonyldi¯uoro-
methyl ꢀEtOCOCF2-) group from ethyl chlorodi¯uoroace-
tate ꢀwith zinc, so called Reformatsky reagent [12±15]) can
also be introduced into naphthalene to give a-EtO2CCF2-
naphthalene which may be further functionalized.
This method has been extended to heteroaromatics, such
as thiophene ꢀ4a), pyrrole ꢀ4b), imidazole ꢀ4c), indole ꢀ4d),
benzofuran ꢀ4e) and quinoline ꢀ5) ꢀScheme 2).
Like in the case with benzenes, the ¯uoroalkyl radical
generated always undergoes substitution at the position with
the richest electron-density on the heteroaromatic rings. For
example, only 2-¯uoroalkylated derivatives were obtained
when pyrrole, indole and benzofuran were treated with
RFCl, respectively ꢀentries 6, 8, 10, 12, and 13, Table 2).
Similarly, 4-¯uoroalkylimidazole was the sole product from
In conclusion, we have developed a ¯uoroalkylation
method of aromatic and heteroaromatic compounds with
Table 1
Reaction results of fluoroalkyl chlorides with aromatics induced by Na2S2O4 in DMSOa
Entry
RFCl ꢀ1)
ArH ꢀ2)
t ꢀh)/T ꢀ8C)
Products ꢀ3)b
Yield ꢀ%)c
1
2
1a
1a
1a
1a
1a
1a
1b
1b
1b
1b
1b
1b
1b
1c
1c
1d
1e
C6H5OCH3 ꢀa)
C6H5NꢀCH3)2 ꢀb)
p-CH3C6H4CH3 ꢀc)
p-CH3OC6H4OCH3 ꢀd)
C6H5NO2
8/75
10/75
8/75
3aa ꢀo:p:m ˆ 50:35:15)
77
57
66
56
3ab ꢀo:p ˆ 21:79)
3
3ac
3ad
4
7.5/80
12/80
10/75
8/75
c
5
±
6
C6H5CF3
<5
78
58
42
58
62
77
64
45
40
61
55
7
C6H5OCH3 ꢀa)
C6H5CH3 ꢀe)
C6H5OH ꢀf)
3ba ꢀo:p:m ˆ 50:40:10)
3be ꢀo:p ˆ 40:60)
3bf ꢀo:p ˆ 70:30)
3bc
8
8/70
9
8/80
10
11
12
13
14
15
16
17
p-CH3C6H4CH3 ꢀc)
p-H2NC6H4Cl ꢀg)
p-CH3OC6H4CH3 ꢀh)
8/75
8/75
3bg
8/80
3bh ꢀo:m ˆ 75:25)
3bi ꢀa:b ˆ 86:14)
3cc
C
10H8 ꢀi)
8/75
p-CH3C6H4CH3 ꢀc)
p-CH3OC6H4OCH3 ꢀd)
C10H8 ꢀi)
10/70
8/75
3cd
3di ꢀa:b ˆ 85:15)
3ei ꢀa:b ˆ 88:12)
7/75
C
10H8 ꢀi)
8/75
a RFCl:ArH:Na2S2O4:NaHCO3 ˆ 1:1.5:1.5:1.5.
b The conversions of RFCl were100% except entry 5 ꢀ0%).
c Isolated yields based on RFCl ꢀexcept entry 6 which was determined by 19F NMR). Approximately 15% of RFH was also obtained.

X.-T. Huang et al. / Journal of Fluorine Chemistry 111 12001) 107±113
109
Scheme 2.
Table 2
3.1. General procedure for the reactions of per
1poly)fluoroalkyl chlorides with electron-rich aromatics
Reaction results of fluoroalkyl chlorides with heteroaromatics induced by
Na2S2O4 in DMSOa
Entry
RFCl ꢀ1) ArH ꢀ4) t ꢀh)/T ꢀ8C)
Products Yield ꢀ%)b
To a 25 ml round bottomed ¯ask, equipped with a mag-
netic stirrer, HꢀCF2)6Cl ꢀ1.04 g, 4 mmol), p-dimethyl ben-
zene ꢀ0.64 g, 6 mmol), Na2S2O4 ꢀ1.04 g, 6 mmol), NaHCO3
ꢀ0.50 g, 6 mmol) and DMSO ꢀ15 ml) were added and the
mixture was stirred at 758C. After 8 h, 19F NMR showed that
the ¯uoroalkyl chloride had disappeared completely, with
about 15% RfH as byproduct. 20 ml H2O was added into the
mixture and the aqueous layer was extracted with ether
ꢀ3 Â 30 ml). The combined extracts were washed with water
and dried over anhydrous Na2S2O4. After the ether had been
removed, the residue was subjected to ¯ash chromatography
on silica gel to give colorless liquid 3bc ꢀ0.94 g, 58%).
1
2
1a
1a
1a
1b
1d
1d
1d
1d
1d
1e
1e
1e
1e
1e
4a
4c
5
8/75
8/75
8/80
7/70
7/75
6/75
7/80
7/75
8/75
6/75
7/75
6/75
7/75
8/75
6aac
6ac
7a
70
63
63
66
66
86
65
71
68
84
67
68
65
55
3
4
4a
4a
4b
4c
4d
4e
4b
4c
4d
4e
5
6bac
6dac
6db
6dc
6dd
6de
6eb
6ec
6ed
6ee
7e
5
6
7
8
9
10
11
12
13
14
3.1.1. CH3OC6H41CF2)4H 1o:p:m ˆ 50:35:15) 13aa)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3009, 2946, 1605, 1589,
1517, 1495, 1466, 1302, 1265, 1204, 1143, 1033, 840, 787,
761. 1H NMR ꢀCCl4) d ꢀppm): 6.1±7.60 ꢀ5H, m), 3.86 ꢀ3H,
s). 19F NMR ꢀCDCl3) d ꢀppm): 29.6 ꢀ0:50 Â 2F, s, o-), 31.4
ꢀ0:35 Â 2F, s, p-), 32.3 ꢀ0:15 Â 2F, s, m-), 46.4 ꢀ2F, s), 52.7
ꢀ2F, s), 60.2 ꢀ2F, d, J ˆ 52 Hz). MS m/z ꢀrelative intensity):
a RFCl:ArH:Na2S2O4:NaHCO3 ˆ 1:2:1.5:1.5.
b Isolated yields based on RFCl with 100% conversion by 19F NMR.
c 2-Fluoroalkyl 3-fluoroalkyl thiophene ˆ 90:10.
per¯uoroalkyl chlorides in the presence of sodium dithionite
in DMSO.
‡
‡
308 ꢀM , 4.61), 307 ꢀM À 1, 38.6), 288 ꢀ3.02), 157 ꢀ100).
HRMS: Calc. for C11H8F8O: 308.0447; found: 308.0451.
3. Experimental
3.1.2. 1CH3)2NC6H41CF2)4H 1o:p ˆ 21:79) 13ab)
IR spectra were recorded on a Shimadzu IR-440 or Perkin
Elmer Jeol 983 spectrometer. 19F NMR spectra were
obtained on a Varian EM-360L ꢀ56.4 MHz) spectrometer
or Bruker AM-300 ꢀ282 MHz) spectrometer usingtri¯uor-
oacetic acid as external standard, down®eld shift being
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3506, 3026, 1602, 1532,
1506, 1448, 1351, 1311, 1220, 1172, 1132, 1067, 821, 756.
1H NMR ꢀCCl4) d ꢀppm): 6.15±7.70 ꢀ5H, m), 3.05 ꢀ6H, m).
19F NMR ꢀCDCl3) d ꢀppm): 27.2 ꢀ0:21 Â 2F, s, o-), 31.9
ꢀ0:79 Â 2F, s, p-), 46.0 ꢀ0:21 Â 2F, s, o-), 47.0 ꢀ0:79 Â 2F, s,
p-), 52.7 ꢀ0:79 Â 2F, s, p-), 53.5 ꢀ0:21 Â 2F, s, o-), 60.1 ꢀ2F,
1
designated as negative. H NMR spectra were carried out
‡
on a Varian EM-390 ꢀ90 MHz) spectrometer with Me4Si as
an external standard or Bruker AM-300 ꢀ300 MHz) spectro-
meter with Me4Si as an internal standard. Mass spectra were
taken on a Hewlett-Packard HP-5989A spectrometer and
HRMS data were obtained on a Finnigan MAT-8430 spec-
trometer. All reactions were routinely monitored by thin
layer chromatography ꢀTLC) or 19F NMR spectroscopy.
d, J ˆ 52 Hz). MS m/z ꢀrelative intensity): 321 ꢀM , 4.97),
‡
320 ꢀM À 1, 37.60), 306 ꢀ4.93), 170 ꢀ59.61), 120 ꢀ100).
HRMS: Calc. for C12H11F8N: 321.0764; found: 321.0766.
3.1.3. p-1CH3)2C6H31CF2)4H 13ac)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3030, 2934, 1626, 1505,
1460, 1363, 1304, 1256, 1045, 880, 818. 1H NMR ꢀCDCl3) d

110
X.-T. Huang et al. / Journal of Fluorine Chemistry 111 12001) 107±113
ꢀppm): 7.11±7.35 ꢀ3H, m), 6.10 ꢀ1H, tt, J ˆ 52, and 5.6 Hz),
2.38 ꢀ3H, s), 2.31 ꢀ3H, s). 19F NMR ꢀCDCl3) d ꢀppm): 28.8
ꢀ2F, s), 45.6 ꢀ2F, s), 52.3 ꢀ2F, s), 59.6 ꢀ2F, d, J ˆ 52 Hz). MS
ꢀ2F, s), 52.8 ꢀ2F, s), 59.8 ꢀ2F, d, J ˆ 52 Hz). MS m/z ꢀrelative
‡
‡
intensity): 394 ꢀM , 0.63), 393 ꢀM À 1, 4.60), 374 ꢀ1.46),
355 ꢀ2.16), 143 ꢀ100). HRMS: Calc. for C12H6F12O:
394.0227; found: 394.0219.
‡
‡
m/z ꢀrelative intensity): 306 ꢀM , 4.94), 305 ꢀM À 1,
38.35), 287 ꢀ1.44), 267 ꢀ1.90), 155 ꢀ100). HRMS: Calc.
for C12H10F: 306.0654; found: 306.0645.
3.1.9. p-H2N1Cl)C6H31CF2)6H 13bg)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3435, 3350, 1615, 1550,
1
3.1.4. p-1CH3O)2C6H31CF2)4H 13ad)
1502, 1405, 1337, 1210, 826. H NMR ꢀCDCl3) d ꢀppm):
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3004, 2957, 1590, 1505,
1466, 1300, 1280, 1237, 1176, 1051, 809. 1H NMR ꢀCDCl3)
d ꢀppm): 6.06±7.05 ꢀ3H, m), 6.02 ꢀ1H, tt, J ˆ 52, and 6 Hz),
3.72 ꢀ6H, m). 19F NMR ꢀCDCl3) d ꢀppm): 30.2 ꢀ2F, s), 46.2
ꢀ2F, s), 52.3 ꢀ2F, s), 60.1 ꢀ2F, d, J ˆ 52 Hz). MS m/z ꢀrelative
6.56±7.45 ꢀ3H, m), 6.00 ꢀ1H, tt, J ˆ 52, and 6 Hz), 4.13 ꢀ2H,
s). 19F NMR ꢀCDCl3) d ꢀppm): 31.8 ꢀ2F, s), 44.6 ꢀ4F, s), 46.2
ꢀ2F, s), 52.5 ꢀ2F, s), 59.8 ꢀ2F, d, J ˆ 52 Hz). MS m/z ꢀrelative
‡
‡
intensity): 429 ꢀM ‡ 2, 27.75), 427 ꢀM , 80.67), 391
ꢀ5.19), 176 ꢀ100). HRMS: Calc. for C12H6ClF12N:
426.9997; found: 426.9997.
‡
‡
intensity): 339 ꢀM ‡ 1, 13.30), 338 ꢀM , 100), 303 ꢀ4.78),
187 ꢀ73.67), 172 ꢀ34.91), 157 ꢀ7.14). HRMS: Calc. for
C12H10F8O2: 338.0553; found: 338.0552.
3.1.10. p-1CH3)1CH3O)C6H31CF2)6H 1o:m ˆ 75:25) 13bh)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3007, 2958, 2841, 1616,
1588, 1507, 1444, 1298, 937, 880, 819, 784, 771. 1H NMR
ꢀCDCl3) d ꢀppm): 6.70±7.30 ꢀ3H, m), 5.96 ꢀ1H, tt, J ˆ 52,
and 6 Hz), 3.70 ꢀ2H, s), 2.25 ꢀ3H, s). 19F NMR ꢀCDCl3) d
ꢀppm): 28.6 ꢀ0:25 Â 2F, s, m-), 30.1 ꢀ0:75 Â 2F, s, o-), 43.6
ꢀ4F, s), 45.7 ꢀ2F, s), 52.3 ꢀ2F, s), 59.5 ꢀ2F, d, J ˆ 52 Hz). MS
3.1.5. CH3OC6H41CF2)6H 1o:p:m ˆ 50:40:10) 13ba)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3009, 2946, 1605, 1589,
1517, 1439, 1402, 1362, 1201, 1143, 1087, 1050, 803, 787,
761. 1H NMR ꢀCDCl3) d ꢀppm): 6.60±7.48 ꢀ4H, m), 5.96 ꢀ1H,
tt, J ˆ 52, and 6 Hz), 3.63 ꢀ3H, s). 19F NMR ꢀCDCl3) d
ꢀppm): 30.2 ꢀ0:5 Â 2F, s, o-), 32.0 ꢀ0:4 Â 2F, s, p-), 33.0
ꢀ0:1 Â 2F, s, m-), 44.0 ꢀ2F, s), 45.8 ꢀ2F, s), 52.1 ꢀ2F, s), 59.9
‡
‡
m/z ꢀrelative intensity): 423 ꢀM ‡ 1, 14.71), 422 ꢀM , 100),
402 ꢀ9.53), 382 ꢀ1.52). HRMS: Calc. for C14H10F12O:
422.0540; found: 422.0538.
‡
ꢀ2F, d, J ˆ 52 Hz). MS m/z ꢀrelative intensity): 408 ꢀM ,
‡
3.70), 407 ꢀM À 1, 26.25), 388 ꢀ2.23), 157 ꢀ100), 107 ꢀ2.35).
HRMS: Calc. for C13H8F12O: 408.0384; found: 408.0385.
3.1.11. p-1CH3)2C6H3CF2CO2Et 13cc)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 2982, 1762, 1616, 1577,
1
3.1.6. p-1CH3)2C6H31CF2)6H 13bc)
1500, 1299, 1266, 1090, 1034, 823. H NMR ꢀCDCl3) d
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3034, 2930, 1623, 1505,
1460, 1405, 1363, 1256, 1200, 1045, 818. 1H NMR ꢀCDCl3)
d ꢀppm): 7.06 ꢀ3H, m), 5.98 ꢀ1H, tt, J ˆ 52, and 6 Hz), 2.28
ꢀ6H, m). 19F NMR ꢀCDCl3) d ꢀppm): 29.2 ꢀ2F, m), 43.5 ꢀ4F,
s), 46.3 ꢀ2F, s), 52.5 ꢀ2F, s), 60.0 ꢀ2F, d, J ˆ 52 Hz). MS m/z
ꢀppm): 7.12±7.39 ꢀ3H, m), 4.32 ꢀ2H, q, J ˆ 7:1 Hz), 2.36
ꢀ6H, m), 1.31 ꢀ3H, t, J ˆ 7:1 Hz). 19F NMR ꢀCDCl3) d
ꢀppm): 23.6 ꢀ2F, s). MS m/z ꢀrelative intensity): 229
‡
‡
ꢀM ‡ 1, 1.78), 228 ꢀM , 13.67), 208 ꢀ5.62), 155 ꢀ100).
HRMS: Calc. for C12H14F2O2: 228.0961; found: 228.0959.
‡
‡
ꢀrelative intensity): 407 ꢀM ‡ 1, 3.12), 406 ꢀM , 19.88),
387 ꢀ2.46), 155 ꢀ100), 105 ꢀ5.50). Analysis: Calc. for
C14H10F12: C, 41.40%; H, 2.48%; F, 56.12%; found: C,
41.82%; H, 2.51%; F, 56.16%.
3.1.12. p-1CH3O)2C6H3CF2CO2Et 13cd)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3045, 2981, 1770, 1594,
1490, 1466, 1286, 1218, 1110, 1047, 827. 1H NMR ꢀCDCl3)
d ꢀppm): 6.56±7.00 ꢀ3H, m), 4.08 ꢀ2H, q, J ˆ 7:0 Hz), 3.70±
3.78 ꢀ6H, m), 1.14 ꢀ3H, t, J ˆ 7:0 Hz). 19F NMR ꢀCDCl3) d
ꢀppm): 25.0 ꢀ2F, s). MS m/z ꢀrelative intensity): 261
3.1.7. CH3C6H41CF2)6H 1o:p ˆ 40:60) 13be)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 2933, 1608, 1495, 1402,
1333, 1255, 1200, 1144, 1041, 823, 734. 1H NMR ꢀCDCl3) d
ꢀppm): 7.46 ꢀ4H, m), 6.00 ꢀ1H, tt, J ˆ 52, and 6 Hz), 2.56
ꢀ3H, m). 19F NMR ꢀCDCl3) d ꢀppm): 29.0 ꢀ0:4 Â 2F, s, o-),
33.3 ꢀ0:6 Â 2F, s, p-), 44.4 ꢀ4F, s), 46.3 ꢀ2F, s), 52.6 ꢀ2F, s),
59.8 ꢀ2F, d, J ˆ 52 Hz). MS m/z ꢀrelative intensity): 393
‡
‡
ꢀM ‡ 1, 18.50), 260 ꢀM , 100), 241 ꢀ30.37), 187
ꢀ23.64), 137 ꢀ6.84). HRMS: Calc. for C12H14F2O4:
260.0860; found: 260.0874.
3.1.13. C10H71CF2)6H 1a:b ˆ 86:14) 13bi)
ꢀM ‡ 1, 1.83), 392 ꢀM , 8.35), 373 ꢀ7.01), 191 ꢀ1.49), 141
ꢀ100), 91 ꢀ15.33). HRMS: Calc. for C13H8F12: 392.0435;
found: 392.0423.
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3258, 1514, 1401, 1290,
1255, 1143, 779, 725, 707. 1H NMR ꢀCDCl3) d ꢀppm): 7.51±
8.25 ꢀ7H, m), 6.05 ꢀ1H, tt, J ˆ 52:0, 5.2 Hz). 19F NMR d
ꢀppm): 27.54 ꢀ0:87  2F, t, J ˆ 15 Hz), 33.25 ꢀ0:13  2F, t,
J ˆ 14:5 Hz), 43.38 ꢀ0:86  2F, s), 44.63 ꢀ1:14  2F, s),
46.53 ꢀ2F, s), 52.78 ꢀ2F, s), 62.2 ꢀ2F, d, J ˆ 52:3 Hz). MS
‡
‡
3.1.8. HOC6H41CF2)6H 1o:p ˆ 70:30) 13bf)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3617, 3048, 1597, 1497,
‡
1
1401, 1333, 1200, 1114, 1037, 728. H NMR ꢀCDCl3) d
m/z ꢀrelative intensity): 428 ꢀM , 23.30), 409 ꢀ1.05), 208
ꢀppm): 6.65±7.49 ꢀ4H, m), 5.96 ꢀ1H, tt, J ˆ 52, and 6 Hz),
5.84±6.38 ꢀ1H, br). 19F NMR ꢀCDCl3) d ꢀppm): 31.0
ꢀ0:7 Â 2F, s, o-), 32.5 ꢀ0:3 Â 2F, s, p-), 44.6 ꢀ4F, s), 46.7
ꢀ3.03), 177 ꢀ100.00), 151 ꢀ3.28), 127 ꢀ4.51), 51 ꢀ3.90).
Analysis: Calc. for C16H8F12: C, 44.86%; H, 1.87%; F,
53.27%; found: C, 44.97%, H, 1.99%; F, 53.56%.

X.-T. Huang et al. / Journal of Fluorine Chemistry 111 12001) 107±113
111
3.1.14. C10H7C6F13 1a:b ˆ 85:15) 13di)
ꢀ0:9  1H, d, J ˆ 5 Hz), 7.64 ꢀ1H, s), 7.16 ꢀ1H, d,
J ˆ 3:3 Hz), 6.08 ꢀ1H, tt, J ˆ 52, 5.4 Hz). 19F NMR d
ꢀppm): 23.76 ꢀ0:9  2F, t, J ˆ 10:8 Hz), 29.1 ꢀ0:1  2F, t,
J ˆ 10:5 Hz), 46.64 ꢀ0:9  2F, t, J ˆ 7:0 Hz), 47.25
ꢀ0:1  2F, t, J ˆ 7:0 Hz), 52.6 ꢀ2F, d, J ˆ 5:3 Hz), 60.3
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3257, 1578, 1514, 1364,
1291, 1241, 1148, 1081, 1029, 865, 821, 739, 725, 709. 1H
NMR ꢀCDCl3) d ꢀppm): 7.51±8.25 ꢀ7H, m), 19F NMR d
ꢀppm): 3.29 ꢀ3F, t, J ˆ 10 Hz), 27.6 ꢀ0:85  2F, t,
J ˆ 15 Hz), 33.3 ꢀ0:15  2F, t, J ˆ 14 Hz), 43.36 ꢀ2F, s),
44.65 ꢀ2F, s), 45.86 ꢀ2F, s), 49.3 ꢀ2F, s). MS m/z ꢀrelative
‡
ꢀ2F, d, J ˆ 48 Hz). MS m/z ꢀrelative intensity): 284 ꢀM ,
18.94), 265 ꢀ8.43), 133 ꢀ100.00), 51 ꢀ6.95). Analysis: Calc.
for C8H4F8S: C, 33.80%; H, 1.41%; found: C: 33.63%; H,
1.46%.
‡
‡
intensity): 447 ꢀM ‡ 1, 10.78), 446 ꢀM , 52.96), 427
ꢀ3.24), 178 ꢀ27.16), 177 ꢀ100.00), 69 ꢀ11.93). Analysis:
Calc. for C16H7F13: C, 43.05%; H, 1.57%; F, 55.30%; found:
C, 42.33%; H, 1.57%; F, 55.54%.
3.2.3. H1CF2)6C4H3S 1a:b ˆ 90:10) 16ba)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3380, 1431, 1200, 1143,
770, 719. 1H NMR ꢀCDCl3) d ꢀppm): 7.1±7.7 ꢀ3H, m), 6.05
ꢀ1H, tt, J ˆ 52, and 5.2 Hz). 19F NMR ꢀCDCl3) d ꢀppm):
23.9 ꢀ0:9  2F, t, J ˆ 14:2 Hz), 29.2 ꢀ0:1  2F, t,
J ˆ 14 Hz), 44.66 ꢀ2F, s), 44.86 ꢀ0:9  2F, t, J ˆ 13 Hz),
45.5 ꢀ0:1  2F, d, J ˆ 13:6 Hz), 46.67 ꢀ2F, s), 60.25 ꢀ2F, d,
3.1.15. C10H7C8F17 1a:b ˆ 88:12) 13ei)
White solid. IR ꢀKBr) ꢀcmÀ1): 1517, 1373, 1248, 1210,
1149, 999, 936, 809, 788, 772, 709, 665. 1H NMR ꢀCDCl3) d
ꢀppm): 7.53±8.25 ꢀ7H, m). 19F NMR d ꢀppm): 3.85 ꢀ3F, t,
J ˆ 10 Hz), 27.5 ꢀ0:88  2F, t, J ˆ 14 Hz), 43.2 ꢀ2F, s),
44.3 ꢀ2F, s), 44.9 ꢀ4F, s), 45.74 ꢀ2F, s), 49.16 ꢀ2F, t,
‡
J ˆ 48 Hz). MS m/z ꢀrelative intensity): 384 ꢀM , 11.30),
‡
J ˆ 14 Hz). MS m/z ꢀrelative intensity): 547 ꢀM ‡ 1,
365 ꢀ7.29), 315 ꢀ4.27), 164 ꢀ9.10), 135 ꢀ5.73), 133 ꢀ100.00),
85 ꢀ11.22), 51 ꢀ9.14). Analysis: Calc. for C10H4F12S: C,
31.25%; H, 1.04%; F, 59.38%; found: C, 31.31%; H, 1.12%;
F, 59.59%.
‡
1.76), 546 ꢀM , 1.38), 527 ꢀ0.83), 226 ꢀ5.90), 208 ꢀ6.43),
177 ꢀ4.19), 69 ꢀ1.84). Analysis: Calc. for C18H7F17: C,
39.56%; H, 1.28%; F, 59.16%; found: C, 39.38%; H,
1.41%; F, 59.59%.
3.2.4. C6F13C4H4N 16db)
Colorless oil. bp 88±908C/20 mmHg. IR ꢀ®lm) ꢀcmÀ1):
3492, 3417, 1693, 1566, 1458, 1419, 1364, 1311, 1081,
3.2. General procedure for the reactions of per
1poly)fluoroalkyl chlorides with heteroaromatic
compounds
1
1039, 957, 884, 857, 821, 804, 781, 714, 669. H NMR
ꢀCDCl3) d ꢀppm): 8.53 ꢀ1H, br), 6.95 ꢀ1H, s), 6.63 ꢀ1H, s),
6.31 ꢀ1H, d, J ˆ 1:0 Hz). 19F NMR ꢀCDCl3) d ꢀppm): 4.02
ꢀ3F, t, J ˆ 9:5 Hz), 30.42 ꢀ2F, t, J ˆ 13:0 Hz), 45.0 ꢀ2F, s),
45.8 ꢀ2F, d J ˆ 13 Hz), 46.1 ꢀ2F, s), 49.4 ꢀ2F, s). MS m/z
Under a nitrogen atmosphere, into a 50 ml three-necked
round-bottomed ¯ask, equipped with a magnetic stirrer,
thermometer, and condenser, was added the mixture of
C6F13Cl ꢀ1.77 g, 5 mmol), thiophene ꢀ840 mg, 10 mmol),
Na2S2O4 ꢀ1.31 g, 7.5 mmol), NaHCO3 ꢀ650 mg, 7.7 mmol),
and DMSO ꢀ10 ml). The mixture was then heated to 758C for
8 h with stirring. The conversion of C6F13Cl was 100%, as
determined by 19F NMR. After cooling, the mixture was
poured into ice water ꢀ15 ml). The aqueous layer was
extracted with ether ꢀ3 Â 20 ml). The combined extracts
were washed with water ꢀ3 Â 20 ml) and dried over Na2SO4.
After removingether, the residue was subjected to column
chromatography on silica gel to afford colorless oil 6da
ꢀ1.33 g, yield 66%).
‡
‡
ꢀrelative intensity): 386 ꢀM ‡ 1, 4.85), 385 ꢀM , 30.67),
366 ꢀ10.16), 347 ꢀ14.49), 178 ꢀ25.82), 147 ꢀ13.19), 116
ꢀ100.00), 69 ꢀ18.24). Analysis: Calc. for C10H4F13N: C,
31.17%; N, 3.64%; F, 64.16%; found: C, 31.23%; H, 1.26%;
N, 3.85%; F, 64.54%.
3.2.5. C8F17C4H4N 16eb)
Colorless oil. bp 112±1148C/20 mmHg. IR ꢀ®lm) ꢀcmÀ1):
3492, 3417, 1693, 1566, 1457, 1419, 1368, 1315, 1081,
1
1038, 983, 888, 843, 819, 776, 712, 672, 649. H NMR
ꢀCDCl3) d ꢀppm): 8.50 ꢀ1H, br), 6.97 ꢀ1H, s), 6.65 ꢀ1H, s),
6.36 ꢀ1H, s). 19F NMR ꢀCDCl3) d ꢀppm): 0.26 ꢀ3F, t,
J ˆ 9:6 Hz), 24.84 ꢀ2F, t, J ˆ 13:5 Hz), 40.1 ꢀ2F, s),
40.43 ꢀ4F, s), 40.82 ꢀ2F, s), 41.27 ꢀ2F, s), 44.78 ꢀ2F, t,
3.2.1. C6F13C4H3S 1a:b ˆ 90:10) 16da)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3400, 1532, 1431, 1363,
‡
1
1242, 1206, 1149, 1091, 716, 651. H NMR ꢀCDCl3) d
J ˆ 14 Hz). MS m/z ꢀrelative intensity): 485ꢀM , 94.03),
ꢀppm): 7.13±7.74 ꢀ3H, m). 19F NMR: d ꢀppm): 3.92 ꢀ3F, s),
24.0 ꢀ0:9  2F, d, J ˆ 12 Hz), 49.3 ꢀ2F, s). MS m/z ꢀrelative
466 ꢀ43.83), 447 ꢀ17.26), 409 ꢀ56.1), 178 ꢀ22.04), 116
ꢀ100.00), 69 ꢀ12.43). Analysis: Calc. for C12H4F17N: C,
29.69%; H, 0.82%; N, 2.87%; F, 66.60%; found: C, 29.52%;
H, 1.00%; N, 2.93%; F, 66.41%.
‡
‡
intensity): 403 ꢀM ‡ 1, 6.31), 402 ꢀM , 45.37), 383
ꢀ20.40), 333 ꢀ11.54), 133 ꢀ100.00), 69 ꢀ3.49). Analysis:
Calc. for C10H3F13S: C, 29.85%; H, 0.75%; found: C,
29.87%; H, 0.90%.
3.2.6. H1CF2)4C3H3N2 16ac)
White solid. IR ꢀKBr) ꢀcmÀ1): 1571, 1464, 1343, 1176,
1
3.2.2. H1CF2)4C4H3S 1a:b ˆ 90:10) 16aa)
1133, 1058, 1041, 937, 869, 840, 807, 770, 632. H NMR
ꢀCD3COCD3) d ꢀppm): 7.87 ꢀ1H, s), 7.7 ꢀ1h, s), 6.8 ꢀ1H, tt,
J ˆ 11:2, and 5.9 Hz), 3.0 ꢀ1H, s). 19F NMR ꢀCD3COCD3) d
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3390, 1431, 1205, 1146,
770, 718. 1H NMR ꢀCDCl3) d ꢀppm): 7.74 ꢀ0:1 Â 1H, s), 7.6

112
X.-T. Huang et al. / Journal of Fluorine Chemistry 111 12001) 107±113
‡
‡
ꢀppm): 27.24 ꢀ2F, s), 43.67 ꢀ2F, s), 48.8 ꢀ2F, d, J ˆ 6 Hz),
57.2 ꢀ2F, d, J ˆ 52 Hz). MS m/z ꢀrelative intensity): 269
ꢀM ‡ 1, 21.19), 535 ꢀM , 100), 516 ꢀ16.47), 197 ꢀ6.65),
167 ꢀ5.53), 166 ꢀ44.10). Analysis: Calc. for C16H6F17N: C,
35.89%; H, 1.12%; N, 3.62%; F, 60.37%; found: C, 35.90%;
H, 1.21%; N, 3.63%; F, 60.05%.
‡
‡
ꢀM ‡ 1, 6.68), 268 ꢀM , 15.16), 249 ꢀ9.56), 199 ꢀ6.11), 148
ꢀ7.01), 117 ꢀ100.00), 90 ꢀ23.01), 51 ꢀ5.73). Analysis: Calc.
for C7H4F8N2: C, 31.34%; H, 1.49%; N, 10.49%; F, 56.72%;
found: C, 31.59%; H, 1.63%; N, 10.43%; F, 56.32%.
3.2.11. C6F13C8H5O 16de)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3430, 1599, 1431, 1364,
1241, 1206, 1148, 831, 748, 715, 669. 1H NMR
ꢀCD3COCD3) d ꢀppm): 7.25±7.74 ꢀ5H, m). 19F NMR
ꢀCD3COCD3) d ꢀppm): 3.8 ꢀ3F, t, J ˆ 10 Hz), 34.9 ꢀ2F, t,
J ˆ 12 Hz), 45.03 ꢀ2F, s), 45.53 ꢀ2F, s), 45.9 ꢀ2F, s), 49.23
3.2.7. C6F13C3H3N2 16dc)
White solid. IR ꢀKBr) ꢀcmÀ1): 1569, 1464, 1368, 1337,
1315, 1245, 1142, 1088, 1057, 978, 840, 721, 649. 1H NMR
ꢀCD3COCD3) d ꢀppm): 7.87 ꢀ1H, s), 7.74 ꢀ1H, s), 2.98 ꢀ1H,
s). 19F NMR ꢀCD3COCD3) d ꢀppm): À0.46 ꢀ3F, t,
J ˆ 10 Hz), 26.9 ꢀ2F, t, J ˆ 13:2 Hz), 40.17 ꢀ2F, s), 40.9
ꢀ2F, d, J ˆ 15 Hz), 41.33 ꢀ2F, s), 44.71 ꢀ2F, t, J ˆ 5 Hz). MS
‡
ꢀ2F, m). MS m/z ꢀrelative intensity): 437 ꢀM ‡ 1, 6.45), 436
‡
ꢀM , 14.34), 198 ꢀ6.57), 167 ꢀ100.00), 119 ꢀ6.89), 69 ꢀ7.08).
Analysis: Calc. for C14H5F13O: C, 38.53%; H, 1.15%; F,
56.65%; found: C, 38.60%; H, 1.18%; F, 56.24%.
‡
‡
m/z ꢀrelative intensity): 387 ꢀM ‡ 1, 5.52), 386 ꢀM ,
16.59), 367 ꢀ17.52), 317 ꢀ4.61), 148 ꢀ9.65), 117 ꢀ100.00),
69 ꢀ9.81). Analysis: Calc. for C9H3F13N2: C, 27.98%; H,
1.05%; N, 7.25%; F, 63.99%; found: C, 27.98%; H, 0.81%;
N, 7.21%; F, 63.95%.
3.2.12. C8F17C8H5O 16ee)
White solid. IR ꢀKBr) ꢀcmÀ1): 1603, 1431, 1373, 1303,
1
1255, 1219, 1145, 973, 912, 883, 758, 713, 673. H NMR
ꢀCD3COCD3) d ꢀppm): 7.67 ꢀ1H, d, J ˆ 7:7 Hz), 7.57 ꢀ1H,
d, J ˆ 8:2 Hz), 7.43 ꢀ1H, t, J ˆ 7:5 Hz), 7.32 ꢀ1H, t,
J ˆ 7:6 Hz), 7.24 ꢀ1H, t, J ˆ 3:3 Hz). 19F NMR
ꢀCD3COCD3) d ꢀppm): 3.82 ꢀ3F, t, J ˆ 10 Hz), 34.93 ꢀ2F,
s), 44.94 ꢀ4F, s), 45.5 ꢀ2F, s), 45.83 ꢀ2F, s), 49.24 ꢀ2F, s). MS
m/z ꢀrelative intensity): 537 ꢀM ‡ 1, 14.87), 536 ꢀM ,
74.58), 517 ꢀ21.40), 198 ꢀ9.04), 168 ꢀ12.43), 167
ꢀ100.00), 101 ꢀ5.91), 69 ꢀ6.08). Analysis: Calc. for
C16H5F17O: C, 35.82%; H, 0.93%; F, 60.26%; found: C,
35.88%; H, 0.92%; F, 59.68%.
3.2.8. C8F17C3H3N2 16ec)
White solid. IR ꢀKBr) ꢀcmÀ1): 1471, 1411, 1371, 1326,
1213, 1148, 1114, 980, 931, 917, 771, 649. 1H NMR
ꢀCD3COCD3) d ꢀppm): 7.47 ꢀ1H, s), 7.24 ꢀ1H, s), 3.07
ꢀ1H, s). 19F NMR ꢀCD3COCD3) d ꢀppm): À0.56 ꢀ3F, t,
J ˆ 9 Hz), 28.5 ꢀ2F, t, J ˆ 10:5 Hz), 40.0 ꢀ2F, s), 40.3 ꢀ4F,
s), 40.8 ꢀ2F, s), 41.15 ꢀ2F, s), 44.62 ꢀ2F, s). MS m/z ꢀrelative
‡
‡
‡
intensity): 486 ꢀM , 14.51), 467 ꢀ15.23), 148 ꢀ9.65), 118
ꢀ6.38), 117 ꢀ100.00), 69 ꢀ8.93). Analysis: Calc. for
C11H3F17N2: C, 27.16%; H, 0.62%; N, 5.76%; F, 66.46%;
found: C, 27.13%; H, 0.60%; N, 6.06%; F, 67.27%.
3.2.13. H1CF2)4C9H6N 17a)
Colorless oil. IR ꢀ®lm) ꢀcmÀ1): 3400, 1576, 1498, 1278,
1172, 1127, 980, 916, 893, 825, 801. 1H NMR ꢀCD3COCD3)
d ꢀppm): 9.07 ꢀ1H, m), 7.66±8.53 ꢀ5H, M), 7.10 ꢀ1H, tt,
J ˆ 51:5, 4.3 Hz). 19F NMR ꢀCD3COCD3) d ꢀppm): 22.8
ꢀ2F, t, J ˆ 9:6 Hz), 40.7 ꢀ2F, t, J ˆ 8 Hz), 48.75 ꢀ2F, d,
J ˆ 5:7 Hz), 57.0 ꢀ2F, d, J ˆ 51 Hz). MS m/z ꢀrelative
3.2.9. C6F13C8H6N 16dd)
White solid. IR ꢀKBr) ꢀcmÀ1): 3404, 1552, 1428, 1368,
1342, 1306, 1235, 1208, 1144, 1091, 1055, 816, 714, 669.
1H NMR ꢀCD3COCD3) d ꢀppm): 7.74 ꢀ1H, d, J ˆ 8 Hz),
7.57 ꢀ1H, d, J ˆ 8:2 Hz), 7.33 ꢀ1H, t, J ˆ 7:5 Hz), 7.18
ꢀ1H, t, J ˆ 7:8 Hz), 7.07 ꢀ1H, s), 3.14 ꢀ1H, s). 19F NMR
ꢀCD3COCD3) d ꢀppm): À0.49 ꢀ3F, t, J ˆ 10 Hz), 26.3 ꢀ2F,
t, J ˆ 13:2 Hz), 40.15 ꢀ2F, s), 40.73 ꢀ2F, s), 41.27 ꢀ2F, s),
44.66 ꢀ2F, t, J ˆ 5 Hz). MS m/z ꢀrelative intensity): 436
‡
‡
intensity): 330 ꢀM ‡ 1, 11.10), 329 ꢀM , 30.84), 328
‡
ꢀM À 1, 29.99), 310 ꢀ6.61), 209 ꢀ8.74), 178 ꢀ100.00),
128 ꢀ10.76), 101 ꢀ6.87), 51 ꢀ8.86). Analysis: Calc. for
C13H7F8N: C, 47.42%; H, 2.13%; N, 4.26%; found: C,
47.42%; H, 2.39%; N, 4.29%.
‡
‡
ꢀM ‡ 1, 17.31), 435 ꢀM , 100), 416 ꢀ14.620), 197 ꢀ5.53),
166 ꢀ90.05), 119 ꢀ5.16), 69 ꢀ9.68). Analysis: Calc. for
C14H6F13N: C, 38.62%; H, 1.38%; N, 3.22%; F,
56.78%; found: C, 38.67%; H, 1.48%; N, 3.29%; F,
56.97%.
3.2.14. C8F17C9H6N 17e)
White solid. IR ꢀKBr) ꢀcmÀ1): 1602, 1580, 1504, 1221,
1
1149, 1078, 1002, 941, 833, 799, 783, 710, 665. H NMR
ꢀCD3COCD3) d ꢀppm): 9.06 ꢀ1H, m), 8.5 ꢀ1H, M), 8.33 ꢀ1H,
d, J ˆ 8:1 Hz), 8.2 ꢀ1H, dt, J ˆ 8:5, 3.0 Hz), 7.84 ꢀ1H, t,
J ˆ 8 Hz), 7.7 ꢀ1H, m). 19F NMR ꢀCD3COCD3) d ꢀppm):
À0.54 ꢀ3F, t, J ˆ 9 Hz), 22.5 ꢀ2F, t, J ˆ 14 Hz), 37.38 ꢀ2F,
s), 39.82 ꢀ2F, s), 40.11 ꢀ4F, s), 40.36 ꢀ2F, s), 41.15 ꢀ2F, s). MS
m/z ꢀrelative intensity): 548 ꢀM ‡ 1, 7.05), 547 ꢀM ,
17.07), 528 ꢀ17.93), 209 ꢀ4.55), 179 ꢀ14.14), 178
ꢀ100.00), 69 ꢀ5.21). Analysis: Calc. for C17H6F17N: C,
37.29%; H, 1.28%; N, 2.56%; F, 59.05%; found: C,
37.32%; H, 1.17%; N, 2.64%; F, 59.00%.
3.2.10. C8F17C8H6N 16ed)
White solid. IR ꢀKBr) ꢀcmÀ1): 3404, 1373, 1308, 1207,
1147, 1115, 983, 915, 810, 748, 712, 670. 1H NMR
ꢀCD3COCD3) d ꢀppm): 7.75 ꢀ1H, d, J ˆ 7:8 Hz), 7.58
ꢀ1H, d, J ˆ 8 Hz), 7.33 ꢀ1H, m), 7.18 ꢀ1H, t,
J ˆ 7:0 Hz), 7.07 ꢀ1H, s), 3.1 ꢀ1H, s). 19F NMR
ꢀCD3COCD3) d ꢀppm): À0.50 ꢀ3F, t, J ˆ 9 Hz), 26.27
ꢀ2F, t, J ˆ 7:3 Hz), 39.9 ꢀ2F, s), 40.3 ꢀ4F, s), 40.55 ꢀ2F,
s), 41.15 ꢀ2F, s), 44.6 ꢀ2F, s). MS m/z ꢀrelative intensity): 536
‡
‡

X.-T. Huang et al. / Journal of Fluorine Chemistry 111 12001) 107±113
113
[5] W.-Y. HuangꢀEd.), Organofluorine Chemistry in China, Shanghai
Acknowledgements
Science and Technology Press, Shanghai, 1996, p. 203.
[6] W.-Y. Huang, W.-P. Ma, J-H. Chen, B. Zan, Youji Huaxue 10 ꢀ1990)
244.
We thank the Chinese National Natural Science Founda-
tion for ®nancial support.
[7] W.-Y. Huang, W.-P. Ma, Chin. Chem. Lett. 2 ꢀ1991) 755.
[8] M. Tordeux, B. Langlois, C. Wakselman, J. Chem. Soc., Perkin
Trans. 1 ꢀ1990) 2293.
[9] Z.-Y. Long, Q.-Y. Chen, Tetrahedron Lett. 39 ꢀ1998) 8487.
[10] Z.-Y. Long, Q.-Y. Chen, J. Org. Chem. 64 ꢀ1999) 4775.
[11] Z.-Y. Long, Q.-Y. Chen, Acta Chim. Sin. 6 ꢀ2000) 713.
[12] E.A. Haldinan, J. Fried, Tetrahedron Lett. 25 ꢀ1984) 2301.
[13] D.J. Burton, Z.-Y. Yang, Tetrahedron 48 ꢀ1992) 189.
[14] T. Ishiharo, Bull. Chem. Soc. Jpn. 63 ꢀ1990) 428.
[15] Y. Shen, M. Qi, J. Chem. Res. ꢀ1993) 222.
References
[1] V.C.R. Mcloughlin, J. Thrower, Tetrahedron 25 ꢀ1969) 5921.
[2] Z.-Y. Yang, Ph.D. Thesis, The Chinese Academy of Sciences,
Shanghai Institute of Organic Chemistry, Shanghai, PR China, 1986.
[3] N. Kamigata, T. Fukushima, M. Yoshida, Chem. Lett. ꢀ1990) 649.
[4] W.-Y. Huang, W.-W. Ying, J.-T. Liu, Chin. J. Chem. 11 ꢀ1993)272.
[16] W.-Y. Huang, W.-W. Ying, Chin. Chem. Lett. 2 ꢀ1991) 607.