Diastereoselectivity-switchable and regiospecific hetero Diels-Alder reaction of N-sulfinylper(poly)fluoroalkanesulfinamides with dienes

Article abstract of DOI:10.1016/j.tet.2005.05.022

N-Sulfinylper(poly)fluoroalkanesulfinamides reacted readily with dienes in methylene chloride at -78°C to give the corresponding cycloadducts with complete regioselectivities and good diastereoselectivities. The diastereoselectivity of the reaction was switchable to the opposite under the catalysis of Lewis acids such as TiCl₄ and SnCl₄.

Full text of DOI:10.1016/j.tet.2005.05.022

Tetrahedron 61 (2005) 6982–6987
Diastereoselectivity-switchable and regiospecific hetero
Diels–Alder reaction of
N-sulfinylper(poly)fluoroalkanesulfinamides with dienes
*
Xiao-Jin Wang and Jin-Tao Liu
Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road,
Shanghai 20032, China
Received 29 December 2004; revised 11 May 2005; accepted 11 May 2005
Available online 4 June 2005
Abstract—N-Sulfinylper(poly)fluoroalkanesulfinamides reacted readily with dienes in methylene chloride at K78 8C to give the
corresponding cycloadducts with complete regioselectivities and good diastereoselectivities. The diastereoselectivity of the reaction was
switchable to the opposite under the catalysis of Lewis acids such as TiCl4 and SnCl4.
q 2005 Elsevier Ltd. All rights reserved.
1. Introduction
the total synthesis of natural products and biologically
active compounds.4 Although the reactions of N-sulfinyl
compounds are well studied, their fluorine-containing
analogs are less reported.5 To the best of our knowledge,
N-sulfinyltrifluoromethanesulfinamide, CF3SONSO, was
first prepared in 1976.6 However, its chemistry has not
been studied yet, neither did the reaction of both
N-sulfinylsulfinamides and their fluorinated analogs. In
order to investigate the reaction of fluorine-containing
N-sulfinyl compounds and synthesize fluorinated sulfur-
containing heterocycles, N-sulfinylper(poly)fluoroalkane-
sulfinamides were prepared and their reaction with dienes
was studied. The results are reported in this paper.
Fluorine-containing heterocycles are fascinating targets for
their unique bioactivities.1 Accordingly, considerable effort
has been devoted to the development of their synthetic
strategies in recent years. Among various reactions
available, hetero Diels–Alder reaction is an extremely
useful method for the synthesis of heterocycles.2 Hetero
Diels–Alder reactions of N-sulfinylaniline and conjugated
dienes were first described by Wichterle and Roceck in
1953. Since then a number of Diels–Alder reactions for
various N-sulfinyl compounds have been reported
(Scheme 1).3 The cycloaddition usually takes place under
mild conditions to afford dihydro-1,2-thiazine-1-oxides,
which are precursors for unsaturated vicinal amino-alcohols
and homoallylic amines, as well as a useful intermediate in
2. Results and discussion
N-Sulfinylper(poly)fluoroalkanesulfinamides (5) were pre-
pared from per(poly)fluoroalkyl iodides (1) as shown in
Scheme 2. Under mild conditions 1 readily reacted with
sodium dithionite to give the corresponding sodium
per(poly)fluoroalkanesulfinates.7 Distillation of the sodium
salts and concentrated sulfuric acid mixture gave free
sulfinic acids 2. Sulfinyl chorides 3 were obtained from 2 by
the treatment with thionylchloride, which were further
treated with hexamethyldisilazane to afford compound 4.
The reaction of 4 with thionylchloride gave 5 in moderate
yields.
Scheme 1.
Keywords: N-Sulfinylper(poly)fluoroalkanesulfinamide; Hetero Diels–
Alder reaction; Diene.
The reaction of 5 with dienes was first carried out at room
temperature. In methylene chloride, compound 5 reacted
*
Corresponding author. Tel.: C86 21 54925188; fax: C86 21 64166128;
e-mail: jtliu@mail.sioc.ac.cn
0040–4020/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2005.05.022

X.-J. Wang, J.-T. Liu / Tetrahedron 61 (2005) 6982–6987
6983
Scheme 2.
Scheme 3.
readily with 2,3-dimethyl-but-1,3-diene (6m) to give the
corresponding cycloadduct 7 as a mixture of syn- and anti-
isomers (Scheme 3). The two isomers could be separated by
column chromatography. Their structures were determined
on the basis of their NMR spectral and X-ray crystal-
lographic study (Fig. 1).
To improve the stereoselectivity of the above reaction,
various conditions were examined. As shown in Table 1, the
ratio of two isomers changed distinctly when Lewis
acids were added to the reaction mixture as a catalyst.
Surprisingly it was found that opposite stereoselectivity was
obtained with the addition of Lewis acids such as TiCl4 and
SnCl4, and TiCl4 gave the best result among the Lewis acids
examined. Temperature also had effect on the stereo-
selectivity of the reaction. Much better stereoselectivities
were obtained when the reaction was carried out at K78 8C
(entries 7 and 9, Table 1). In all reactions, per(poly)fluoro-
alkanesulfinamides, RfSONH2, were formed as a by-product
from the hydrolysis of 5 although the reaction was carried
out under inert and anhydrous conditions.
The effect of TiCl4 on the reaction diastereoselectivity
might be explained as follows. The cycloaddition of
N-sulfinyl compounds with dienes has been proved to be
pericyclic.8 The weight of evidence is that N-sulfinyl
compounds exists in ground states in the Z configuration
about the N]S double bond.9 In the absence of TiCl4, the
dienophile prefers conformation A to minimize the electro-
static interaction between the two sulfinyl oxygens,10
Figure 1. Molecular structure of 7bm.
Table 1. The reaction of 5 and 6m under different conditions
Entry
Rf
Temperature
Catalyst
Product
Yield (%)a
syn/anti
1
2
3
4
5
6
7
8
9
10
ClC2F4
ClC2F4
ClC2F4
ClC2F4
ClC2F4
ClC2F4
ClC2F4
ClC2F4
C4F9
rt
rt
rt
rt
rt
—
BF3$Et2O
ZnCl2
AlCl3
SnCl4
TiCl4
—
TiCl4
—
TiCl4
7am
7am
7am
7am
7am
7am
7am
7am
7bm
7bm
66
71
54
68
72
66
79
59
74
70
15:85
18:82
15:85
37:63
73:27
85:15
7:93
98:2
5:95
94:6
rt
K78 8C
K78 8C
K78 8C
K78 8C
C4F9
a Isolated yields based on 5.

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X.-J. Wang, J.-T. Liu / Tetrahedron 61 (2005) 6982–6987
electrophilic N-sulfinyl compounds had better regio-
selectivity in the hetero Diels–Alder reactions with dienes
on the basis of the Hu¨ckel frontier orbital approach and
experimental evidence.8 So it is clear that the regio-
selectivity of this reaction is attributed to the strong
electron-withdrawing ability of perfluoroalkylsulfinyl group.
Figure 2.
Table 2. The cycloaddition reaction of 5 and asymmetrical dienesa
Entry
Rf
Diene
Catalyst
Product
Yield (%)b
syn/anti
1
2
3
4
5
6
ClC2F4
ClC2F4
C4F9
C4F9
ClC2F4
C4F9
6n
6n
6n
6n
6l
—
TiCl4
—
TiCl4
—
—
7an
7an
7bn
7bn
7al
55
64
66
62
76
72
26:74
87:13
28:72
90:10
24:76
16:84
6l
7bl
a All reactions were carried out at K78 8C.
b Isolated yields based on 5.
In summary, the cycloaddition reaction of N-sulfinyl-
per(poly)fluoroalkanesulfinamides with dienes has been
demonstrated, providing a facile method for the preparation
of per(poly)fluoroalkanesulfinyl substituted dihydro-1,2-
thiazine-1-oxides with complete regioselectivity and good
diastereoselectivity.
3. Experimental
Figure 3. NOE correlations from NOESY spectra of 7bn.
1
Melting points were uncorrected. H NMR spectra were
recorded in CDCl3 on a Bruker AM-300 spectrometer
(300 MHz) with TMS as internal standard. 19F NMR spectra
were taken on a Bruker AM-300 (282 MHz) spectrometer
using CFCl3 as external standard. IR spectra were obtained
with a Nicolet AV-360 spectrophotometer. Mass spectra
and high resolution mass spectra (HRMS) were obtained on
a Finnigan GC-MS 4021 and a Finnigan MAT-8430
spectrometer, respectively. Dichloromethane was distilled
from CaH2 and reagents were purified before use.
Compound 5 was easy to hydrolyse and stored in CH2Cl2
solution.
resulting in the predominant formation of anti cycloadducts
when reacted with dienes (Fig. 2). While in the presence of
TiCl4 the reaction takes place through the chelating
complex B, formed by the bonding of metal cation and
two sulfinyl oxygens. Thus, the other side is the most
accessible for the approach of the diene and opposite
stereoselectivity is obtained.
To demonstrate the regioselectivity of this reaction,
reactions of 5 and some asymmetrical dienes were
investigated using the optimized conditions (Scheme 4).
The results are summarized in Table 2. The cycloaddition of
5b and 6n gave only two isomers as indicated by 19F NMR
spectra of the crude products. Their structures were
determined on the basis of NOESY spectra of purified
products (Fig. 3). This indicated that the reaction proceeded
in a completely regioselective manner with good dia-
stereoselectivities. Similar results were reported in the
literatures.8,11 Hanson and Stockburn reported that less
3.1. General procedure for the synthesis of per(poly)-
fluoroalkanesulfinic acids 2
With magnetic stirring, a mixture of Na2S2O4 (34.8 g,
0.2 mol) and NaHCO3 (16.8 g, 0.2 mol) was added to the
mixture of per(poly)fluoroalkyl iodides 1 (0.15 mol),
180 mL H2O and 120 mL CH3CN at room temperature.
Scheme 4.

X.-J. Wang, J.-T. Liu / Tetrahedron 61 (2005) 6982–6987
6985
After addition, the mixture was stirred for a few hours at
room temperature to the completion of reaction (monitored
by 19F NMR). The resulting mixture was extracted with
ethyl acetate (100 mL!4). The combined organic layer was
washed with saturated aqueous NaCl solution (100 mL!3)
and dried over anhydrous Na2SO4. After the removal of
solvent, the residue was dissolved in 120 mL of concen-
trated H2SO4 and distilled under reduced pressure to give 2
as a colorless oil.
3.3.1.
sulfinamide (4a). Oil. Bp 62–63 8C/0.1 Torr. FT-IR
(film): 1260, 1172, 1127, 1016, 911 cmK1 1H NMR
N-Trimethylsilyl-2-chlorotetrafluoroethane-
.
(300 MHz, CDCl3): d 0.28 (s, 9H), 5.01 (s, 1H). 19F NMR
(282 MHz, CDCl3): d K67.1 (m, 2F), K110.1, K126.21
(AB, JABZ232.2 Hz, 2F). EIMS (m/z, %): 272 (MCC1,
0.02), 100 (7.30), 85 (12.22), 73 (17.31), 66 (7.13), 64
(100.00), 48 (11.80), 47 (6.59), 46 (13.23). HRMS: calcd for
C5H10ClF4NNaOSSi: 293.9769. Found: 293.9767.
3.1.1. 2-Chlorotetrafluoroethanesulfinic acid (2a). Color-
less oil. Bp 62–63 8C/1 Torr. FT-IR (film): 2910, 1273,
3.3.2. N-Trimethylsilyl-nonafluorobutanesulfinamide
(4b).12 Oil. Bp 52–53 8C/0.01 Torr. FT-IR (film): 3221,
1353, 1237, 1142, 852 cmK1. 1H NMR (300 MHz, CDCl3):
d 0.31 (s, 9H), 4.82 (s, 1H). 19F NMR (282 MHz, CDCl3): d
K81.2 (m, 3F), K120.1, K128.2 (AB, JABZ234.9 Hz, 2F),
K122.3 (m, 2F), K126.6 (m, 2F). EIMS (m/z, %): 131
(13.37), 100 (10.37), 69 (40.57), 66 (7.80), 64 (100.00), 48
(21.41), 47 (7.99), 46 (19.98).
1
1167 cmK1. H NMR (300 MHz, CDCl3): d 10.28 (s, 1H).
19F NMR (282 MHz, CDCl3): d K68.30 (m, 2F), K122.34
(m, 2F). EIMS (m/z, %): 201 (MCC1, 0.74), 135 (17.37),
116 (15.21), 100 (34.39), 85 (46.53), 65 (100.00), 50
(17.45), 48 (22.70), 45 (15.82). Anal. Calcd for C2HClF4-
O2S: C, 11.98; H, 0.50. Found: C, 12.07; H, 0.66.
3.1.2. Nonafluorobutanesulfinic acid (2b).12 Colorless oil.
Bp 65–66 8C/1 Torr. FT-IR (film): 3397, 1299, 1254, 1291,
3.4. General procedure for the synthesis of N-sulfinyl-
per(poly)fluoroalkanesulfinamides 5
1
1141 cmK1. H NMR (300 MHz, CDCl3): d 9.60 (s, 1H).
19F NMR (282 MHz, CDCl3): d K81.21 (t, JZ7.6 Hz, 3F),
K122.77 (m, 2F), K123.24 (m, 2F), K126.59 (m, 2F).
EIMS (m/z, %): 285 (MCC1, 0.67), 169 (16.24), 150
(19.38), 131 (30.83), 119 (28.92), 100 (29.85), 69 (100.00),
65 (78.37), 45 (44.44).
To thionyl chloride (3.7 mL, 0.05 mol) was added slowly
N-(trimethylsilyl)-perfluoroalkanesulfinamide (0.05 mol)
by a syringe pump at room temperature. After addition,
the mixture was stirred at room temperature for a few hours
to the completion of reaction (monitored by 19F NMR). The
resulting mixture was distilled under reduced pressure to
give 5.
3.2. General procedure for the synthesis of perfluoro-
alkanesulfinyl chlorides 3
3.4.1. N-Sulfinyl-2-chlorotetrafluoroethanesulfinamide
(5a). Oil. Bp 60 8C/15 Torr. FT-IR (film): 1236, 1168,
Perfluoroalkanesulfinic acid 2 (0.1 mol) was added drop-
wise to thionylchloride (7.4 mL, 0.1 mol) with stirring at
0 8C. After the addition, stirring was continued for 2 h at
room temperature. The product was purified by distillation
under reduced pressure.
1122, 1075, 1015, 801 cm .
K1 19F NMR (282 MHz, CDCl3):
d K66.8 (m, 2F), K112.6, K116.5 (AB, JABZ223.1 Hz,
2F). EIMS (m/z, %): 245 (MC, 2.04), 202 (37.62), 201
(8.47), 200 (100.00), 85 (11.30), 64 (93.32), 48 (23.14), 47
(12.46), 46 (33.93). Anal. Calcd for C2ClF4NO2S2: C, 9.78;
N, 5.70. Found: C, 9.95; N, 5.90.
3.2.1. 2-Chlorotetrafluoroethanesulfinyl chloride (3a).
Colorless oil. Bp 58 8C/160 Torr. FT-IR (film): 1262, 1202,
1176, 1121, 1010, 792 cm .
K1 19F NMR (282 MHz, CDCl3):
3.4.2. N-Sulfinylnonafluorobutanesulfinamide (5b). Oil.
Bp 66–67 8C/15 Torr. FT-IR (film): 1353, 1236, 1212, 1141,
d K66.98 (m, 2F), K110.55, K117.60 (AB, JAB
Z
218.8 Hz, 2F). EIMS (m/z, %): 218 (MC, 0.26), 151
(17.33), 137 (34.02), 135 (100.00), 100 (28.19), 87 (20.08),
85 (81.31), 83 (69.59), 48 (22.11). Anal. Calcd for
C2Cl2F4OS: C, 10.97. Found: C, 10.94.
1109, 726, 696 cmK1 19F NMR (282 MHz, CDCl3): d
.
K81.2 (m, 3F), K114.1, K117.1 (AB, JABZ291.5 Hz, 2F),
K121.4 (m, 2F), K126.6 (m, 2F). EIMS (m/z, %): 329
(MC, 4.49), 284 (100.00), 282 (13.08), 131 (10.04), 69
(31.29), 64 (91.92), 48 (39.24), 47 (13.61), 46 (44.27).
HRMS: calcd for C4F9NO2S2: 328.9227. Found: 328.9261.
3.2.2. Nonafluorobutanesulfinyl chloride (3b).12 Colorless
oil. Bp 33–34 8C/40 Torr. FT-IR (film): 1719, 1351, 1239,
1140, 111, 747, 723 cmK1 19F NMR (282 MHz, CDCl3): d
.
3.5. General procedure for the reaction of N-sulfinyl-
per(poly)fluoroalkanesulfinamides 5 and dienes
K81.4 (m, 3F), K111.2, K117.3 (AB, JABZ233.57 Hz,
2F), K120.8 (m, 2F), K126.5 (m, 2F). EIMS (m/z, %): 169
(14.44), 131 (41.30), 119 (20.89), 100 (26.67), 69 (100.00),
65 (74.98), 48 (13.85), 47 (20.63).
To a flame-dried flask were added N-sulfinylper(poly)fluoro-
alkanesulfinamide 5 (1 mmol), Lewis acid (1.2 mmol) and
dry CH2Cl2 (5 mL) at K78 8C under N2 atmosphere. After
stirring for 30 min, diene (2 mmol) was added to the
solution via a syringe and the mixture was stirred for 8 h.
The reaction mixture was diluted with dichloromethane and
washed with saturated aqueous NaHCO3 solution and
saturated aqueous NaCl solution, dried over anhydrous
Na2SO4. After the removal of solvent, the residue was
purified by chromatography on silica gel using ethyl acetate/
hexane (v/v: 1:8) as elute to give compound 7.
3.3. General procedure for the synthesis of N-(trimethyl-
silyl)perfluoroalkanesulfinamides 4
To NH(SiMe3)2 (16 mL, 0.075 mol) was added dropwise
perfluoroalkanesulfinyl chlorides (0.075 mol) at 0 8C. After
addition, stirring was continued for 2 h at room temperature.
The product was purified by distillation under reduced
pressure.

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X.-J. Wang, J.-T. Liu / Tetrahedron 61 (2005) 6982–6987
3.5.1.
4,5-Dimethyl-2-(2-chlorotetrafluoroethane-
(m, 2F), K111.8, K117.0 (AB, JABZ228.4 Hz, 2F) (anti);
K67.8 (m, 2F), K109.8, K117.5 (AB, JABZ222.8 Hz, 2F)
(syn). EIMS (m/z, %): 361 (47.58), 360 (14.22), 359
(100.00), 289 (7.76), 237 (15.70), 209 (9.09), 176 (6.46),
135 (9.73). Anal. Calcd for C7H8ClF4NO2S2: C, 26.80; H,
2.57; N, 4.46. Found: C, 26.52; H, 2.49; N, 4.57.
sulfinyl)-3,6-dihydro-2H-[1,2]thiazine-1-oxide (7am).
syn Isomer. White solid, mp 72–73 8C. FT-IR (KBr):
1185, 1161, 1119, 1095, 1056, 883, 796 cmK1. H NMR
1
(300 MHz, CDCl3): d 1.82 (s, 6H), 3.30, 3.75 (AB, JAB
Z
15.9 Hz, 2H), 3.96, 4.09 (AB, JABZ15.6 Hz, 2H). 19F NMR
(282 MHz, CDCl3): d K68.0 (m, 2F), K110.1, K117.9
(AB, JABZ228.0 Hz, 2F). EIMS (m/z, %): 328 (MCC1,
0.16), 144 (91.12), 129 (52.85), 95 (61.46), 94 (58.44), 81
(72.41), 67 (100.00), 41 (92.50), 39 (56.36). Anal. Calcd for
C8H10ClF4O2S2: C, 29.32; H, 3.08; N, 4.27. Found: C,
29.17; H, 3.35; N, 4.31.
3.5.4. 5-Methyl-2-nonafluorobutanesulfinyl-3,6-dihydro-
2H-[1,2]thiazine-1-oxide (7bn). syn Isomer. White solid,
mp 70–71 8C. IR (KBr): 1352, 1237, 1202, 1181 cmK1. 1H
NMR (300 MHz, CDCl3): d 1.88 (s, 3H), 3.32, 3.72 (AB,
JABZ16.5 Hz, 2H), 4.06, 4.31 (AB, JABZ16.5 HZ, 2H),
5.78–5.79 (m, 1H). 19F NMR (282 MHz, CDCl3): d K81.0
(t, JZ12.4 Hz, 3F), K110.8, K119.1 (AB, JABZ238.3 Hz,
2F), K122.1 (m, 2F), K126.3 (m, 2F). EIMS (m/z, %): 398
(MCC1, 0.70), 178 (100.00), 130 (36.47), 115 (36.47), 82
(38.20), 81 (56.63), 80 (39.97), 67 (45.27), 53 (40.51). Anal.
Calcd for C9H8F9NO2S2: C, 27.21; H, 2.03; N, 3.53. Found:
C, 27.16; H, 2.19; N, 3.47.
anti Isomer. White solid, mp 61–62 8C. FT-IR (KBr): 2932,
1174, 1154, 1013, 796 cmK1. 1H NMR (300 MHz, CDCl3):
d 1.83 (s, 6H), 3.27, 3.56 (AB, JABZ16.2 Hz, 2H), 3.76,
4.05 (AB, JABZ17.1 Hz, 2H). 19F NMR (282 MHz,
CDCl3): d K67.8 (m, 2F), K111.7, K116.9 (AB, JAB
Z
229.0 Hz, 2F). EIMS (m/z, %): 328 (MCC1, 42.60), 192
(80.64), 144 (100.00), 129 (72.26), 95 (67.83), 94 (53.71),
81 (64.48), 67 (63.46), 41 (68.69). Anal. Calcd for
C8H10ClF4O2S2: C, 29.32; H, 3.08; N, 4.27. Found: C,
29.46; H, 3.26; N, 4.25.
anti Isomer. White solid, mp 63–64 8C. IR (KBr): 2980,
1
1358, 1263, 1241 cmK1. H NMR (300 MHz, CDCl3): d
1.90 (s, 3H), 3.28, 3.54 (AB, JABZ16.5 Hz, 2H), 3.98, 4.14
(AB, JABZ18.3 Hz, 2H), 5.81–5.82 (m, 1H). 19F NMR
(282 MHz, CDCl3): d K81.0 (t, JZ9.3 Hz, 3F), K112.3,
K119.3 (AB, JABZ239.7 Hz, 2F), K122.4 (m, 2F), K126.4
(m, 2F). EIMS (m/z, %): 398 (MCC1, 0.32), 178 (100.00),
115 (42.25), 81 (14.52), 69 (56.52), 68 (68.58), 67 (86.68), 53
(49.56), 41 (55.38). Anal. Calcd for C9H8F9NO2S2: C, 27.21;
H, 2.03; N, 3.53. Found: C, 27.16; H, 2.26; N, 3.47.
3.5.2. 4,5-Dimethyl-2-(nonafluorobutanesulfinyl)-3,6-
dihydro-2H-[1,2]thiazine-1-oxide (7bm). syn Isomer.
White solid, mp 74–75 8C. IR (KBr): 1249, 1221, 1196,
1108, 997, 884 cmK1. 1H NMR (300 MHz, CDCl3): d 1.82
(s, 6H), 3.31, 3.78 (AB, JABZ16.2 Hz, 2H), 3.95, 4.11 (AB,
JABZ14.9 Hz, 2H). 19F NMR (282 MHz, CDCl3): d K81.0
(m, 3F), K110.8, K119.2 (AB, JABZ238.8 Hz, 2F),
K122.1 (m, 2F), K126.3 (m, 2F). EIMS (m/z, %): 412
(MCC1, 0.20), 192 (55.40), 144 (100.00), 129 (47.89), 95
(53.78), 81 (59.71), 69 (58.95), 67 (73.08), 41 (63.63). Anal.
Calcd for C10H10F9NO2S2: C, 29.20; H, 2.45; N, 3.41.
Found: C, 29.34; H, 2.48; N, 3.34.
3.5.5. 5-(4-Methylpent-3-enyl)-2-(2-chlorotetrafluoro-
ethanesulfinyl)-3,6-dihydro-2H-[1,2]-thiazine-1-oxide
(7al). FT-IR (KBr): 1162, 1120, 1014, 793 cmK1. 1H NMR
(300 MHz, CDCl3): d 1.62 (s, 3H), 1.70 (s, 3H), 2.12–2.16
(m, 4H), 3.27–3.73 (m, 2H), 3.96–4.36 (m, 2H), 5.07–5.08
(m, 1H), 5.77–5.81 (m, 1H). 19F NMR (282 MHz, CDCl3): d
K67.9 (m, 2F), K111.8, K116.6 (AB, JABZ229.3 Hz, 2F)
anti Isomer. White solid, mp 69–70 8C. IR (KBr): 1239,
1197, 1177, 1148 cmK1. H NMR (300 MHz, CDCl3): d
(anti); K67.8 (m, 2F), K111.0, K117.6 (AB, JABZ
1
1.82–1.85 (m, 6H), 3.30, 3.57 (AB, JABZ16.2 Hz, 2H),
3.78, 4.06 (AB, JABZ17.4 Hz, 2H). 19F NMR (282 MHz,
CDCl3): d K80.9 (t, JZ12.1 Hz, 3F), K112.1, K119.2
(AB, JABZ242.5 Hz, 2F), K122.4 (m, 2F), K126.3 (m,
2F). EIMS (m/z, %): 412 (MCC1, 6.55), 129 (37.62), 95
(43.84), 94 (50.25), 81 (50.25), 69 (69.61), 53 (39.71), 41
(63.63). Anal. Calcd for C10H10F9NO2S2: C, 29.20; H, 2.45;
N, 3.41. Found: C, 29.20; H, 2.50; N, 3.37. Crystallographic
data (excluding structure factors) for the structures in this
paper have been deposited with the Cambridge Crystal-
lographic Data Centre as supplementary publication
numbers CCDC 248677 and 248678. Copies of the data
can be obtained, free of charge, on application to CCDC, 12
Union Road, Cambridge CB2 1EZ, UK [fax: C44(0) 1223
336033 or e-mail: deposit@ccdc.cam.ac.uk].
222.8 Hz, 2F) (syn). EIMS (m/z, %): 183 (32.40), 169
(27.93), 134 (30.80) 133 (31.11), 107 (33.41), 105 (26.35),
80 (28.02), 67 (26.17). Anal. Calcd for C12H16ClF4NO2S2: C,
37.75; H, 4.22; N, 3.67. Found: C, 37.73; H, 4.13; N, 3.71.
3.5.6. 5-(4-Methylpent-3-enyl)-2-nonafluorobutane-
sulfinyl-3,6-dihydro-2H-[1,2]thiazine-1-oxide (7bl). FT-
IR (KBr): 1352, 1236, 1214, 1179, 1139, 1109, 1092 cmK1
.
1H NMR (300 MHz, CDCl3): d 1.61 (s, 3H), 1.70 (s, 3H),
2.00–2.17 (m, 4H), 3.29–3.56 (m, 2H), 3.97–4.19 (m, 2H),
5.07–5.12 (m, 1H), 5.80–5.81 (m, 1H). 19F NMR (282 MHz,
CDCl3): d K80.9 (m, 3F), K111.2, K119.0 (AB, JAB
252.1 Hz, 1.7F, anti isomer), K110.8, K119.0 (AB, JAB
Z
Z
237.7 Hz, 0.3F, syn isomer), K122.1 (m, 2F), K126.3 (m,
2F). EIMS (m/z, %): 246 (53.79), 183 (26.28), 135 (28.17),
121 (37.53), 93 (50.94), 91 (27.37), 69 (100.00), 41 (97.84).
Anal. Calcd for C14H16F9NO2S2: C, 36.13; H, 3.47; N, 3.01.
Found: C, 36.27; H, 3.47; N, 2.98.
3.5.3. 5-Methyl-2-(2-chlorotetrafluoroethanesulfinyl)-
3,6-dihydro-2H-[1,2]thiazine-1-oxide (7an). FT-IR
(KBr): 2979, 2316, 1169, 1142, 1112 cmK1 1H NMR
.
(300 MHz, CDCl3): d 1.88 (s, 3H), 3.25, 3.53 (AB, JAB
15.9 Hz, 2H), 3.96, 4.12 (AB, JABZ17.1 Hz, 2H), 5.79–
5.81 (m, 1H) (anti); 1.86 (s, 3H), 3.28, 3.68 (AB, JAB
Z
Acknowledgements
Z
16.2 Hz, 2H), 4.03, 4.27 (AB, JABZ16.5 Hz, 2H), 5.76–
We thank the National Natural Science Foundation of China
for financial support (No. 20172065).
5.77 (m, 1H) (syn). 19F NMR (282 MHz, CDCl3): d K67.9

X.-J. Wang, J.-T. Liu / Tetrahedron 61 (2005) 6982–6987
6987
7. Hu, L. Q.; Huang, W. Y. Youji Huaxue (Chin. J. Org. Chem.)
1991, 11, 126–132.
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