A novel example of vinylic SRN1: Reactions of 3,3-difluoro-1-iodo-2-phenylcyclopropene with thiolate ions

Article abstract of DOI:10.1016/j.jfluchem.2006.02.005

The reactions of 3,3-difluoro-1-iodo-2-phenylcyclopropene with thiolate ions (with a molar ratio of 1:1) were carried out in laboratory illumination to give the corresponding substituted product. The presence of p-dinitrobenzene (p-DNB) or hydroquinone (HQ) as well as darkness significantly suppressed the reaction. ESR trapping experiments also evidenced the existence of fluorinated radical. All these results demonstrate the reaction involved a vinylic saturated alkyl and aromatic halides (S_RN1) mechanism.

Full text of DOI:10.1016/j.jfluchem.2006.02.005

Journal of Fluorine Chemistry 127 (2006) 740–745
www.elsevier.com/locate/fluor
A novel example of vinylic S 1: Reactions of 3,3-difluoro-1-iodo-2-
RN
phenylcyclopropene with thiolate ions
a
Ding-Ying Zhou , Hong-Yan Dou , Cheng-Xue Zhao , Qing-Yun Chen
b
b
a,*
a
Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China
b
Department of Chemistry, Shanghai Jiaotong University, Shanghai 200240, China
Received 11 January 2006; received in revised form 10 February 2006; accepted 13 February 2006
Available online 6 March 2006
Abstract
The reactions of 3,3-difluoro-1-iodo-2-phenylcyclopropene with thiolate ions (with a molar ratio of 1:1) were carried out in laboratory
illumination to give the corresponding substituted product. The presence of p-dinitrobenzene ( p-DNB) or hydroquinone (HQ) as well as darkness
significantly suppressed the reaction. ESR trapping experiments also evidenced the existence of fluorinated radical. All these results demonstrate
the reaction involved a vinylic saturated alkyl and aromatic halides (SRN1) mechanism.
#
2006 Elsevier B.V. All rights reserved.
Keywords: Vinylic SRN1; Fluorine; Thiolate
1
. Introduction
(Eq. (4)). In comparison with these well-established mechan-
ism for saturated alkyl and aromatic systems, the study on the
radical nucleophilic substitution of vinylic counterpart, i.e.
SRN1(V), is rarely reported. Thanks to the elaborate work by
Rappoport and co-workers [7], we now know that the SRN1(V)
is not a common route due to severe competition by other polar
routes, but it takes place, indeed, with substrates of well-defined
structures [7a]. The vinyl substrates in favor of SRN1(V) rather
The unimolecular radical nucleophilic substitution of
saturated alkyl and aromatic halides (SRN1) is one of the most
important kinds of single electron-transfer (SET) reactions in
organic chemistry [1,2]. Their chain steps are shown in
Eqs. (1)–(4).
ꢀ
ꢁꢀ
RX þ e ! RX
(1)
(2)
(3)
(4)
than S 2, elimination-addition etc., should be: (1) without both
N
ꢁ
ꢀ
ꢁ
ꢀ
a–C–H and b-C–H bonds, (2) having a conjugated vinylic p-
substituent, (3) bearing electron-withdrawing group(s) on the
double bond. Meanwhile, it is pivotal to find a delicate balance
among the predominance of the three-fold nature, i.e. its basic,
reducing and nucleophilic character of an attacking anion in
order to suppress the side pathways [7,8]. In connection with
our long lasting interest in SET of organofluorine compounds
[9], we have examined the possibility of SRN1(V) of b-fluoro-
RX Ð R þ X
ꢁ
ꢀ
ꢁꢀ
R þ Nu Ð RNu
RNu þ RX Ð RNu þ RXꢁꢀ
ꢁ
ꢀ
The initiation step (Eq. (1)) can occur by photostimulation
3], electrochemical reduction [4] or spontaneous electron
[
transfer from Nu to the substrate RX [5]. The alkyl or aryl
ꢀ
ꢁ
alkyl vinyl iodides (R
with thiolate ions (RS , R = Ph, ClC H , C H , CH CHCH2)
F
ꢀ
CH CHI, R
F
= ClC
F , n-C F , n-C F )
4 8 2 5 4 9
radical R , which generated in fast collapse of radical anion
ꢀ
ꢁ
ꢀ
6
4
2
5
2
RX (Eq. (2)), combines with Nu yielding a new radical
ꢀ
[10]. Although the vinyl substitution products (R CH CHSR)
F
ꢁ
ꢁꢀ
anion RNu
molecular ET [6] with RX to give the natural substitution
(Eq. (3)). Then RNu
undergoes an inter-
were obtained in high yields, but the SET inhibitor, p-
dinitrobenzene ( p-DNB), could not suppress the reaction.
These indicate that the reaction is a simple elimination-addition
process but not a SRN1(V) in character. However, a recently
reported fluorinated compound [11], 3,3-difluoro-1-iodo-2-
phenyl-cyclopropene (1), obtained easily, was anticipated to be
ꢁ
ꢀ
product RNu and RX
which turns on the chain cycling
*
Corresponding author. Tel.: +86 21 54925196; fax: +86 21 64166128.
E-mail address: Chenqy@mail.sioc.ac.cn (Q.-Y. Chen).
0022-1139/$ – see front matter # 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jfluchem.2006.02.005

D.-Y. Zhou et al. / Journal of Fluorine Chemistry 127 (2006) 740–745
741
Table 2
a
The reaction of 1 with excess of 2 in DMF under laboratory illumination
b
b
Entry Compounds 2 1:2 Time (h) Conversion (%) Yield (%)
3
6
4
5
1
2
3
4
2b
2c
2c
2d
1:10 48
1:2.5 18
1:5 18
1:2.5 20
100
100
100
92
100
1
–
–
c
c
33 0 75 77
0 30 100
10 77 28
Scheme 1.
0
–
a
b
c
NaH:1 = 1:1, all the reactions were carried out at room temperature.
19
Based on F NMR.
Table 1
The reaction of 1 with 2 in DMF under laboratory illumination
19
With a cis–trans ratio of 2:1 by F NMR.
a
Entry
Compounds
Time
(h)
Conversion
b
(%)
Yield of 3
(%)
Yield of 4
(%)
c
d
2
besides the main product 3. Thus, the reactions of 1 with excess
thiol 2 were carried out (see Scheme 2, Table 2).
A similar reaction of 1 with excess of benzenethiol (2a)
resulted in producing even none of 3 but a saturated cycl-
opropane 6a along with a ring-opening product 7 (Scheme 3).
In order to gain deeper insight into the mechanism,
inhibition experiments, i.e. addition of SET scavenger, p-
dinitrobenzene, or free radical inhibitor, hydroquinone (HQ),
to the reaction mixture, as well as the reaction in dark were
carried out.
1
2
3
4
2a
2b
2c
2d
4
5
5
5
100
90
3a
3b
3c
96
90
50
70
4a
4b
4c
4d
2
9
e
57
40
20
e
78
3d
a
1
:2:NaH = 1:1:1.
Based on the recovery of 1.
19
Based on F NMR.
b
c
d
e
Based on the amount of 2 used.
A small amount of difluorocyclopropane 5 was also obtained.
Importantly, for an effective comparison of the conversion of
1 in the presence of additives, a suitable reaction temperature
and time for each thiolate ion should be set because various
thiolate ions showed different reactivity toward 1 as mentioned
above.
an ideal candidate for SRN1(V) because it is fully satisfied with
above mentioned structural requirements. Herein, we present
the results.
The reaction temperature, time and conversion of 1 are
listed in Table 3. The ratio of 1:2:NaH was also controlled
as 1:1:1 in all the reactions, because the reaction become
more complex in the presence of excess thiol 2 as shown in
Table 2.
2
. Results and discussion
ꢀ
We chose thiolate ions RS (2) as nucleophiles, because they
are weak base and still have decent reducing ability which are
ꢀ
favorable for SRN1 reactions [7]. The thiolate ion RS (2)
generated in situ from thiol in a suspension of sodium hydride in
DMF reacted with 3,3-difluoro-1-iodo-2-phenyl-cyclopropene
The data in Table 3 showed that the conversion of 1 clearly
decreased (25–18% for 2a–2d) in dark as compared with that
under laboratory illumination. The presence of p-DNB
significantly suppressed the reaction for 2a (37%), 2b
(27%), 2c (29%), moderately for 2d (6%). All these results
demonstrated that a vinylic SRN1 (SRN1(V)) mechanism are
involved in the reactions.
(1) at room temperature for 4–5 h to give the corresponding
substituted product 3 in good yield along with some amounts of
disulfide 4 (Scheme 1). The results are listed in Table 1.
The data in Table 1 showed that the reactivity of aryl thiolate
ions is, as expected, better than that of alkyl thiolate ions, i.e.
Finally, it was necessary to seek for support from ESR
detection of radical intermediate. The reaction of 1 with thiol 2c
was chosen as a representative.
2
might imply free radical mechanism [12]. All the compounds
a > 2b > 2d > 2c. The existence and isolation of disulfide 4
1
19
were determined unambiguously by H, F NMR, IR as well as
mass spectroscopy and HRMS.
Sodium 3,5-dibormo-4-nitrosobenzene-sulphonate (DBN
BS, 8) was used as a trapping reagent [13]. Neither a solution
of 1 or 8 in DMF nor the thiolate anion of 2c in DMF solution
gave ESR signal. But the mixture of 1 and 2c in DMF displayed
Because in Entries 3 and 4, when the ratio of 1:2 was 1:1, a
small amount of difluorocyclopropane 5 was also detected
Scheme 2.

742
D.-Y. Zhou et al. / Journal of Fluorine Chemistry 127 (2006) 740–745
Scheme 3. The reaction of 1 and 2a, with a ratio of 1:2a:NaH = 1:10:1.
Table 3
Influences of additive on the reactions of 1 and 2 in DMF
a
b
Entry
1
Additive (% mol)
Temperature (8C)
ꢀ18
Time (min)
5
Conversion of 1–3 (%)
c
lab.ill.
89
in dark
ꢀ18
ꢀ20
ꢀ20
24
5
5
64
52
67
93
71
66
82
40
15
11
31
19
1
lab.ill. + p-DNB(20)
lab.ill. + HQ(20)
c
lab.ill.
5
2
3
4
20
20
20
20
30
30
30
30
30
30
30
30
in dark
24
lab.ill. + p-DNB(20)
24
lab.ill. + HQ(20)
c
lab.ill.
24
16
in dark
16
lab.ill. + p-DNB(20)
16
lab.ill. + HQ(20)
c
lab.ill.
16
22
in dark
22
lab.ill. + p-DNB(20)
lab.ill. + HQ(20)
22
13
17
22
a
Products 3, 4 are shown in Scheme 1.
b
c
19
Determined by F NMR.
Lab. ill.: laboratory illumination.
a signal with splitting by un-equivalent two fluorine atoms (see
Fig. 1).
same ESR pattern. But it is not the case. Thus, the ESR
spectrum (Fig. 2(a)) clearly indicates the successfully trapping
of radical I by 8 to affording spin adduct IVA.
To further prove the existence of radical intermediate I, spin
trapping experiment was carried out [14]. By mixing 1 and 2c
with trapping reagent 8, a well-resolved triplet characteristic of
nitroxide radical was recorded and shown in Fig. 2(a).
In the reaction of 1, 2c and 8, three possible radicals, i.e. I, II
and III may be generated and trapped by 8 to give the
corresponding spin adducts IVA, IVB and IVC (Schemes 4 and
The facts that the reactions are retarded by p-DNB and HQ
and in dark and the proof of ESR spectrum provide evidences
for a new vinylic SRN1 of 1 with thiolate ions. This process
could be initiated by spontaneous or thermal electron transfer
between thiolate ion and 1, because the reactions can occur in
dark. The whole process may be described by Eqs (1)–(4) if RX
ꢀ
5
). In order to exclude the possibility of IVB and IVC, a DMF
is 3,3-difluoro-1-iodo-2-phenyl -cyclopropene (1) and Y is
ꢀ
solution containing 8 and thiolate anion of 2c was tested by
ESR spectrometer (Scheme 5) [15]. It was found that the ESR
spectrum obtained (see Fig. 2(b)) is quite different from that
shown in Fig. 2(a). If II or III was trapped, it would afford the
RS .
As for the formation of other products 5, 6 and 7 generated in
the reactions of 1 with excess thiolates, much more work are
needed to make it clear.
Fig. 1. ESR spectrum of the reaction mixture of 1 and 2c, and a possible reaction intermediate structural assignment.

D.-Y. Zhou et al. / Journal of Fluorine Chemistry 127 (2006) 740–745
743
ꢀ
Fig. 2. ESR spectrum of IVA (a
formed in the reaction of t-BuS with DBNBS.
N
ꢀ
= 13.2 G) (a) generated in the reaction of 1 with t-BuS in the presence of DBNBS, and of IVC (a
N
= 8.5 G, a
F
= 1.27 G), (b)
Scheme 4.
Scheme 5.
3
. Conclusion
NMR spectra were recorded on a Bruker AM-300 (300 MHz)
1
9
spectrometer with TMS as an internal standard. F NMR
spectra were recorded on a Bruker AM-300 (282 MHz)
In summary, we have disclosed a new example of vinylic
SRN1, i.e. the reaction of 3,3-difluoro-1-iodo-2-phenylcyclo-
1
spectrometer using CFCl as an external standard. C NMR
3
3
propene (1) with thiolate ions (molar ratio = 1:1).
spectra were recorded on a Bruker AM-300 (75 MHz)
spectrometer. The solvent for NMR measurement was CDCl3.
EPR spectra were recorded on a Bruker EMX-8 spectrometer.
GC–MS were performed on a Finnigan MD800 instrument.
Column chromatography was carried out on silica gel H (10–
40 mm).
4
. Experimental
General: DMF is distilled from calcium hydride. The IR
1
spectra were recorded on a Shimadzu IR-440 spectrometer. H

744
D.-Y. Zhou et al. / Journal of Fluorine Chemistry 127 (2006) 740–745
1
4
.1. Typical procedure for the equal mole reaction of 1 and
4d H NMR (300 MHz, CDCl ) d 7.32–7.29 (m, 4H), 7.18–
3
+
7.15 (m, 4H), 3.59 (s, 4H); MS (70 eV) m/z 317 (M + 2, 0.32),
2
+
+
+
3
16 (M + 1, 2.01), 315 (M , 0.52), 314 (M ꢀ 1, 2.59), 157
Under a nitrogen atmosphere, t-BuSH (2c) (0.23 mL,
mmol) was added into a stirred suspension of NaH (60%,
0 mg, 2 mmol) in DMF (2 mL). The mixture, after becoming
(1.23), 125 (100); in accordance with Ref. [16].
2
8
4.2. Typical procedure for the reaction of 1 with excess of
thiol 2
clear, was dropped into a solution of 1 (556 mg, 2 mmol) in
DMF (2 mL). The resulting mixture was stirred at room
temperature for 5 h, then diluted with Et O (80 mL). The
2
Under a nitrogen atmosphere, 2c (0.43 mL, 3.75 mmol) was
addedintoastirredsuspensionofNaH(60%,60 mg,1.5 mmol)in
DMF (2 mL). After the mixture became clear, a solution of 1
(417 mg, 1.5 mmol) in DMF (1 mL) was added. The resulting
mixturewasstirredatroomtemperaturefor18 h,thendilutedwith
solution was washed with water (4 ꢂ 15 mL), then brine. The
organic phase was dried over Na SO , filtered, and
4
2
concentrated under vacuum. The residue was purified by
flash chromatography with petroleum ether as eluant.
Products 3c and 4c were obtained in 12% and 40% yield,
respectively.
Et O(60 mL). Thesolutionwaswashedwithwater(4 ꢂ 10 mL),
2
andthenbrine.TheorganicphasewasdriedoverNa SO ,filtered,
2
4
ꢀ
1
3
a: colorless oil. IR (film) n (cm ): 3061, 2926, 2854, 1747,
andconcentratedundervacuum.Theresiduewaspurifiedbyflash
chromatography with petroleum ether as eluent. Products 4c and
5c were obtained in 75% and 77% yield, respectively.
1
1
579, 1477,1440,1293, 1231, 1045, 1024, 827; H NMR
300 MHz, CDCl ) d 7.66–7.62 (m, 2H), 7.55–7.46 (m, 3H),
1
.39–7.33 (m, 3H), 7.19–7.16 (m, 2H); F NMR (282 MHz,
(
3
9
ꢀ1
7
5c: colorless oil. IR (film) n (cm ): 2967, 1431, 1367, 158,
+
1
986, 697; trans: H NMR (300 MHz, CDCl ) d 7.37–7.23 (m,
CDCl ) d ꢀ104.92 (s, 2F); MS (70 eV) m/z 260 (M , 12.68),
3
3
1
9
5H), 2.83–2.67 (m, 2H), 1.40 (s, 9H); F NMR (282 MHz,
2
7
2
10 (7.76), 183 (16.27), 151 (32.70), 110 (100.00), 109 (51.94),
7 (24.48); HRMS Calcd. for C H F S 260.04713, found
CDCl ) d = ꢀ136.22 (dd, J = 148.3 Hz, J = 12.9 Hz, 1F),
1
5
10
2
3
1
60.04796.
a: colorless oil. H NMR (300 MHz, CDCl ) d 7.57–7.51
m, 4H); 7.39–7.30 (m, 6H); MS (70 eV) m/z 218 (M , 73.86),
41 (4.76), 109 (100.00), 77 (12.69); in accordance with Ref.
16].
b: pale yellow oil. IR (film) n (cm ): 3065, 2925, 2854,
ꢀ131.04 (dd, J = 149.5 Hz, J = 11.0 Hz, 1F); cis: H NMR
19
1
4
(300 MHz, CDCl ) d 7.36–7.29 (m, 5H), 3.15 (t, J = 11.7 Hz,
3
3
+
(
1H), 2.93 (t, J = 12 Hz, 1H), 1.32 (s, 9H); F NMR (CDCl ) S
3
1
ꢀ144.88 (d, J = 152.3 Hz, 1F), ꢀ120.43 (dd, J = 152.3 Hz,
+
+
[
J = 113.0 Hz, 1F); MS (70 ev) m/z 243 (M +1, 15.65), 242 (M ,
1.88), 186 (3.61), 153 (17.86), 133 (35.24), 77 (0.96), 57
(100.00); Anal. Calcd. for C H F S: C 64.43, H 6.66, F 15.68,
ꢀ
1
3
1
1
745, 1579, 1493, 1449, 1290, 1254, 1018, 828; H NMR
300 MHz, CDCl ) d 7.49 (d, J = 8.1 Hz, 2H), 7.37–7.31 (m,
1
3
16
2
(
found C 64.28, H 6.63, F 15.69.
3
ꢀ
1
3
H), 7.24 (d, J = 8.1 Hz, 2H), 7.13 (d, J = 7.5 Hz, 2H), 2.41
1
6a: colorless oil. IR (film) n (cm ): 3060, 2921, 2851, 1583,
9
1
1418, 1282, 1181, 1024, 942; H NMR (300 MHz, CDCl ) d
7.67–7.64 (m, 2H), 7.47–7.45 (m, 3H), 7.34–7.27 (m, 8H), 7.11
(
(
s, 3H); F NMR (282 MHz, CDCl ) d ꢀ105.75 (s, 2F); MS
3
3
+
70 eV) m/z (%) 274 (M , 5.31), 259 (14.38), 240 (1.12),
1
(d, J = 4.8 Hz, 2H), 3.42 (d, J = 13.2 Hz, 1H); C NMR
3
183 (10.24), 151 (100.00), 123 (12.30), 91 (5.73), 77 (8.94);
+
GC–MS m/z (%) 274 (M , 33), 259 (100), 183 (30), 151
(75.5 MHz, CDCl ) d 133.51, 132.69, 132.26, 131.15, 130.14,
3
(
58); HRMS Calcd. for C H F S 274.06278, found
6 12 2
129.50, 129.24, 128.94, 128.84, 128.39, 128.11, 127.44, 77.22,
1
1
9
2
74,06332.
1
42.75;
J = 143.5 Hz, J = 13.0 Hz, J = 4.23 Hz, 1F), ꢀ131.76 (d,
F NMR (282 MHz, CDCl ) d ꢀ119.51 (ddd,
3
4
.10 (d, J = 8.1 Hz, 4H), 2.31 (s, 6H); GC–MS m/z 246 (M ,
b H NMR (300 MHz, CDCl ) d 7.38 (d, J = 8.1 Hz, 4H),
3
+
+
J = 144.1 Hz, 1F); MS (70 ev) m/z 370 (M , 1.75), 292
7
1
00), 123 (9.00); in accordance with Ref. [16].
ꢀ
(2.01), 261 (28.26), 241 (12.81), 153 (22.33), 121 (100.00), 109
(27.85), 77(66.27); Anal. Calcd. for C H F S : C 68.07, H
4.36, F 10.26, found C 67.81, H 4.35, F 10.36.
1
3
607, 1500, 1430, 1294, 1156, 1025, 816; H NMR (300 MHz,
c: pale yellow oil. IR (film) n (cm ): 2966, 2868, 1718,
2
1 16 2 2
1
1
CDCl ) d 7.67–7.64 (m, 2H), 7.49–7.45 (m, 3H), 1.39 (s, 9H);
ꢀ
1
6d: colorlesss oil. IR (film) n (cm ): 2929, 1414, 1208,
3
1
9
1
1174, 1092, 933, 694; H NMR (300 MHz, CDCl ) d 7.31–7.26
F NMR (282 MHz, CDCl ) d ꢀ106.88 (s, 2F); MS (70 eV) m/
3
3
+
z 221 (M ꢀF, 0.73), 183 (1.85), 151 (19.74), 89 (3.69), 77
(m, 7H), 7.19 (d, J = 8.4 Hz, 2H), 7.12–7.10 (m, 2H), 7.03 (d,
J = 8.4 Hz, 2H), 4.09 (d, J = 12.9 Hz, 1H), 4.02 (d, J = 12.9 Hz,
1H), 3.85 (d, J = 12.3 Hz, 1H), 3.54 (d, J = 12.3 Hz, 1H), 3.04
(5.07), 57 (100.00), 41 (40.94); HRMS (MALDI) Calcd. for
C H F SNa 263.06820, found 263.06765.
+
1
3 14 2
1
19
4
m/z 178 (M , 23.31), 122 (14.94), 89 (0.57), 57 (100.00), 41
c H NMR (300 MHz, CDCl ) d 1.31 (s, 18H); MS (70 eV)
(dd, J = 13.2 Hz, J = 2.4 Hz, 1H); F NMR (282 MHz, CDCl3)
d ꢀ120.89 (dd, J = 149.2 Hz, J = 14.1 Hz, 1F), ꢀ136.00 (d,
3
+
+
J = 149.2 Hz, 1F); MS (70 ev) m/z 341 (M -CH C H -Cl-p,
(
23.73); in accordance with Ref. [16].
2
6 4
ꢀ1
3
597, 1490, 1418, 1298, 1093, 1042, 826; H NMR (300 MHz,
d: pale yellow oil. IR (film) n (cm ): 3029, 2868, 1746,
5.91), 322 (2.49), 291 (0.34), 152 (0.37), 125 (100.00), 89
(12.86); Anal. Calcd. for C H F Cl S : C 59.10, H 3.88, F
8.13, found C 59.09, H 3.99, F 8.36.
1
1
CDCl ) d 7.33–7.19 (m, 9H), 3.56 (s, 2H); F NMR (282 MHz,
2
3
18
2
2 2
1
9
3
+
ꢀ1
CDCl ) d ꢀ104.23 (s, 2F); MS (70 eV) m/z 308 (M , 0.30), 183
7: colorless oil. IR (film) n (cm ): 3058, 2922, 1582, 1477,
3
1
1439, 1225, 740, 688; H NMR (300 MHz, CDCl ) d 7.65 (d,
(
17.76), 151 (2.30), 144 (0.17), 143 (0.49), 125 (100.00), 77
3.23); HRMS Calcd. for C H ClF S 308.0238, found
3
(
J = 7.5 Hz, 2H), 7.57 (d, J = 6.9 Hz, 2H), 7.44–7.36 (m, 6H),
7.24–7.15 (m, 6H), 6.97 (d, J = 7.5 Hz, 2H), 6.90–6.86 (m, 2H),
1
6
11
2
3
08.0255.

D.-Y. Zhou et al. / Journal of Fluorine Chemistry 127 (2006) 740–745
745
1
3
[
3] (a) R.A. Rossi, S.M. Palacios, J. Org. Chem. 46 (1981) 5300–5304;
b) G.L. Borosky, A.B. Pierini, R.A. Rossi, J. Org. Chem. 57 (1992) 247–
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6
.23 (dd, J = 28.5 Hz, J = 3.0 Hz, 1H); C NMR (75.5 MHz,
CDCl ) d 134.56, 133.08, 131.93, 129.47, 129.33, 129.24,
(
3
2
1
1
29.07, 128.89, 128.80, 128.64, 128.55, 128.40, 128.39,
9
28.35, 127.60, 127.35, 126.92, 112.20, 53.01; F NMR
(
1
3
(282 MHz CDCl ) d ꢀ86.61 (d, J = 29.0 Hz, 1F); MS (70 ev)
m/z 351 (M -SPh, 66.60), 241 (100.00), 221 (21.14), 133
3
+
7
[
(
[
65.45), 109 (28.04), 77 (20.46); m/z (MALDI) 483.1
+
M + Na , 4%], 351.1 [100%]; HRMS (MALDI) Calcd. for
1
(
+
C H FS Na : 483.06871, found 483.06816.
2
7
21
3
6872–6879.
[
[
[
5] A.N. Santiago, A.E. Stanl, G.L. Rodriguez, R.A. Rossi, J. Org. Chem. 62
(
1997) 4406–4411.
6] J.M. Saveant, C.P. Andrieux, M. Robert, J. Am. Chem. Soc. 116 (1994)
864–7871.
7] (a) C. Galli, Z. Rappoport, Eur. J. Org. Chem. (2002) 2136–2143;
b) C. Galli, Z. Rappoport, Acc. Chem. Res. 36 (2003) 580–587.
4
.3. The typical inhibition experiment
7
Under N atmosphere, t-BuSH (2c) (56 mL, 0.5 mmol) was
2
added into a stirred suspension of NaH (60%, 20 mg, 0.5 mmol)
in DMF (0.5 mL). After becoming clear, the mixture was
dropped into a solution of 1 (139 mg, 0.5 mmol) in DMF
(0.5 mL). The resulting mixture was stirred at room tempera-
ture for 30 min under laboratory light, then cold water (2 mL)
(
[8] (a) A. Pross, Theoretical and Physical Principals of Organic Reactivity,
Wiley, New York, 1995;
(
(
b) F.G. Bordwell, Acc. Chem. Res. 21 (1988) 456–463;
c) R.G. Pearson, H. Sobel, J. Songstad, J. Am. Chem. Soc. 90 (1968)
3
19–326;
1
9
was added. The mixture was extracted with ether (20 mL).
NMR analysis of the organic layer indicated that the conversion
F
(
d) C. Galli, P. Gentili, Acta Chem. Scand. 53 (1998) 67–76;
(e) L. Eberson, Acta Chem. Scand. B38 (1984) 439–459.
9] (a) Q.Y. Chen, Israel J. Chem. 39 (1999) 179–192;
19
[
of 1 was 40%. When the reaction proceeded in dark, F NMR
analysis indicated that the conversion was 15%. When p-DNB
(
(
(
(
b) Q.Y. Chen, Z.M. Qiu, J. Fluorine Chem. 31 (1986) 301–317;
c) Q.Y. Chen, Z.M. Qiu, J. Fluorine Chem. 35 (1987) 343–357;
d) Q.Y. Chen, Z.M. Qiu, J. Chem. Soc. Chem. Comm. (1987) 1240–1241;
e) Q.Y. Chen, M.J. Chen, J. Fluorine Chem. 51 (1991) 21–32;
(16 mg, 0.1 mmol) was present, after stirring for 30 min under
laboratory light, the reaction was treated with the same
1
9
procedure as mentioned above. F NMR analysis of the
resulting organic layer showed 11% conversion of 1.
Similarly, when HQ (10 mg, 0.1 mmol) was present instead
(f) Z.T. Li, Q.Y. Chen, J. Chem. Soc. Perkin Trans. 1 14 (1993) 1705–1710;
(
(
(
(
(
g) Y. Guo, Q.Y. Chen, Acta Chim. Sin. 59 (2001) 1722–1729;
h) Y. Zhao, W. Li, Q.Y. Chen, C.X. Zhao, Res. Chem. Intermediates 27
2001) 287–296;
1
9
of p-DNB, F NMR analysis showed 31% conversion of 1.
i) A.R. Li, Q.Y. Chen, J. Fluorine Chem. 82 (1997) 151–155;
j) Z.T. Li, Q.Y. Chen, J. Chem. Soc. Perkin Trans. 1 (1992) 1443–1445;
Acknowledgement
(k) M.F. Chen, Z.T. Li, Q.Y. Chen, J. Chem. Soc. Perkin Trans. 2 (1991)
071–1075;
1
(
(
(
l) Z.Y. Long, Q.Y. Chen, J. Fluorine Chem. 91 (1998) 95–97;
We thank the financial support of Natural Science foundation
of China (Nos. 20272026, 20532040 and D20032010).
m) C.X. Zhao, M. Gamil, C. Walling, J. Org. Chem. 48 (1983) 4908–4910;
n) C.X. Zhao, X.K. Jiang, J. Am. Chem. Soc. 108 (1986) 3132–3133.
[
10] X.T. Huang, Q.Y. Chen, Acta Chim. Sin. 10 (2000) 1296–1300.
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(
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(
[
[
[
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1
[
(
(
(
(
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(
(
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2
724.
(