Synthesis of six- to nine-membered ring oximinoorthodithiolactones by cyclization of nitroketene S,S-acetals in trifluoromethanesulfonic acid

Article abstract of DOI:10.1002/1099-0690(200104)2001:8<1525::AID-EJOC1525>3.0.CO;2-O

2-Nitro-1,1-bis(phenylalkylthio)ethene or 1-(methylthio)-2-nitro-1-(phenylalkylthio)ethene derivatives tethered to an aromatic ring undergo a fast intramolecular cyclization in trifluoromethanesulfonic acid, with the intermediate formation of dications, which can be detected by NMR spectroscopy. Quenching with methanol at low temperature affords cyclic orthothioesters of isothiochromanones, 4,5-dihydrobenzo[d]-thiepin-1-one, 5,6-dihydro-4H-benzo[d]thiocin-1-one and 8,9,10,11-tetrahydro-7-thiabenzocyclononen-5-one oximes. The yields are usually fair to good, except for the nine-membered ring derivatives.

Full text of DOI:10.1002/1099-0690(200104)2001:8<1525::AID-EJOC1525>3.0.CO;2-O

FULL PAPER
S S
Sulfur heterocycles / Superacidic systems / Carbocations / Aromatic substitution
2-Nitro-1,1-bis(phenylalkylthio)ethene or 1-(methylthio)-2-
orthothioesters of isothiochromanones, 4,5-dihydrobenzo[d]-
nitro-1-(phenylalkylthio)ethene derivatives tethered to an thiepin-1-one, 5,6-dihydro-4H-benzo[d]thiocin-1-one and
aromatic ring undergo a fast intramolecular cyclization in tri-
fluoromethanesulfonic acid, with the intermediate formation
8,9,10,11-tetrahydro-7-thiabenzocyclononen-5-one oximes.
The yields are usually fair to good, except for the nine-mem-
of dications, which can be detected by NMR spectroscopy. bered ring derivatives.
Quenching with methanol at low temperature affords cyclic
omethanesulfonic acid (TFSA or trific acid), 1-heterosub-
stituted-2-nitroethene derivatives , with either nitrogen or
sulfur as heteroatoms, are kinetically diprotonated to form
cations . They are then transformed into conjugated dicat-
ions with a heterosubstituted carbocationic center and a
hydroxynitrilium site Ϫ or O-protonated nitrile oxide Ϫ as
shown in Scheme 1.
Nitroethene derivatives are well-known synthons in or-
ganic chemistry. For instance, they are used in the field of
drug synthesis[1,2] and for intramolecular cyclizations invol-
ving nitrile oxides (INOC reaction).[2,3] Generally, thio de-
rivatives also tend to be useful synthetic substrates, for ex-
ample, in heterocyclic synthesis using tandem reactions.
This good reactivity is due to the formation of transient
thiocarbenium cations that react with nitrogen or in an ene-
type reaction.[4] Thiocarbenium cations are formed either
from a sulfoxide in a Pummerer-type reaction,[5,6] from di-
thioacetals treated with dimethyl(methylthio)sulfonium
tetrafluoroborate,[4Ϫ7] or by α-halogenation of sulfides.[8] α-
Halosulfites are useful reagents as aldehyde or ketone
equivalents that can react either as nucleophiles by halogen
substitution or as electrophiles in the presence of Lewis ac-
ids. Superelectrophilic methylthiomethylation of aromatic
rings with a thio-substituted carbenium ion generated un-
der superacidic conditions are also reported.[9]
1,1-Bis(methylthio)-2-nitroethene ( ) is also a good
starting substrate for various syntheses because of the easy
nucleophilic substitution of both MeS groups.[10Ϫ12] Reac-
tions with aromatic[13] or nonaromatic amines[14] afford
nitroketene S,N-acetals. An intermediate in the manufac-
ture of the anti-ulcer drug ranitidine can be prepared in this
way.[15] Nitroketeneaminals are obtained by nucleophilic
substitution of both MeS groups with an amine group.[16]
Similar reactions with Grignard reagents are also re-
ported.[18]
Scheme 1. Reactivity of heterosubstituted nitroethylene derivatives
in triflic acid
These cations were observed by 1H and 13C NMR
spectroscopy.[21Ϫ23] They are fair electrophiles that react
with various nucleophiles to afford, in agreement with
theoretical considerations,[24,25] the kinetic product
in
which the attacking group and the OH oxime group are in
cis configuration.[26,27]
In the present paper, the reactivity of conjugated hydro-
xynitrilium ions is applied to new syntheses in the field of
sulfur heterocyclic compounds. New derivatives such as or-
thodithioesters of thiochromanone, 4,5-dihydrobenzo[d]-
thiepin-1-one, 5,6-dihydro-4H-benzo[d]thiocin-1-one and
8,9,10,11-tetrahydro-7-thiabenzocyclononen-5-one oximes
were easily prepared.
Cyclic tetrathioorthocarbonates and cyclic trithioorthoe-
sters are also potential reagents to afford alkenes by Ni-
catalyzed cross-coupling reactions with Grignard re-
agents.[19] Cyclic orthotrithioesters are also used in the field
of sugar synthesis.[20] In the superacids HF/SbF5 or trifluor-
[a]
´
Faculte des Sciences, Laboratoire de Chimie 12, UMR CNRS
6514,
Starting compounds
equiv. of the corresponding phenylalkyl bromide with di-
potassium salt in DMSO, and starting compound
Ϫ were obtained from 2 mol-
40, Avenue du Recteur Pineau, 86022 Poitiers, France
Fax: (internat.) ϩ 33-5/49453501
E-mail: jean-marie.coustard@gmx.net
Ϫ
Eur. J. Org. Chem.
, 1525Ϫ1531
WILEY-VCH Verlag GmbH, 69451 Weinheim, 2001
1434Ϫ193X/01/0408Ϫ1525 $ 17.50ϩ.50/0
1525

J.-M. Coustard
FULL PAPER
were obtained from 1 mol-equiv. of the corresponding benium center and a hydroxyiminium group. The dithiocar-
phenylalkyl bromide followed by the addition of 1 mol- benium carbon atoms resonate in the range δC
equiv. of iodomethane (Figure 1). 209.1Ϫ220.9 and the hydroxyiminium carbon atoms be-
tween δC ϭ 148.2 and 159.0. Figure 2 shows the observed
NMR spectra for cation
ϭ
.
Figure 1. Starting products
used for their synthesis
Ϫ
and
Ϫ and dipotassium salt
Starting materials have not been described before, except
for 1,1-bis(benzylthio)-2-nitroethene ( ).[28] The products
were purified by flash chromatography, followed by crystal-
lization from various solvents to eliminate a small amount
of co-eluted yellow compounds.
Compounds
mers in organic solvent solutions. The NMR spectra of
are characterized by: (i) the presence of signals as-
Ϫ exist as mixtures of (Z) and (E) iso-
Ϫ
signed to two vinylic protons at δH ഠ 7.0 (∆δH for the two
isomers in the range 0.02Ϫ0.20 ppm), (ii) by two sets of
signals for C-1 at δC ഠ 163.5 (∆δC ϭ 0.12Ϫ0.36 ppm) and
for the C-2 at δC ϭ 124.5 (∆δC ϭ 0.3Ϫ0.95 ppm). Such a
rotation about a CϪC double bond in solution was previ-
ously reported for the thio derivative , with both methyl
protons giving rise to one signal at room temperature, and
a
coalescence temperature of approximately
0
°C
(60 MHz).[29] In the present study, this equilibrium was also
observed by HPLC for compounds Ϫ , as indicated by
their plateau-like elution profiles. Such an elution behavior
Figure 2. NMR spectra of cyclic cation
in trifluoromethanesul-
fonic acid at room temp. (reference TMS in [D4]methanol)
In both cases, the more shielded carbon atoms are ob-
is typical for quickly equilibrating isomers during analysis, served in the six-membered series, probably because of the
as reported for other products either on analytical or on conformation of the nonaromatic ring, which allows for
theoretical grounds.[30Ϫ32]
some kind of conjugation with the aromatic ring,[34] as ob-
served with cation
in the acyclic series (Figure 3).[21] The
increase in the ring size may also account for the increase
in the chemical shift, as observed with cyclic ketones.[35]
In the present study, the reactions were carried out in
trifluoromethanesulfonic acid at 0 °C or at lower temper-
ature under nitrogen. The thio derivatives were added to
cold, stirred trifluoromethanesulfonic acid. The trifluoro-
methanesulfonic acid/thio derivative molar ratio was Ͼ
50:1. At the end of the reaction, the acidic solution was
poured into a mixture of methanol/CH2Cl2 (about 15:85 v/
v) at Ϫ60 to Ϫ80 °C. The extraction was carried out at
approximately 0 °C, as described in the Exp. Sect. The reac-
Figure 3. Acyclic cation
previously observed
The formation of cations
Ϫ
and
Ϫ may be ex-
plained in the light of previously observed reactions in the
acyclic series: Starting products undergo multiple pro-
tonation, leading quickly to the formation of conjugated
hydroxynitrilium cation , which were not observed. As
tions were usually clean, except with
and
for which
polar by-products were formed, probably because of extens-
ive intermolecular reactions.[33] By-products were also ob-
served in the reactions with , with longer reaction times,
or at higher temperatures, probably because of the reactivity
of the second tethered phenyl ring.
soon as it is formed, the cation
reacts with the tethered
phenyl ring by means of an electrophilic aromatic substitu-
tion mechanism, to afford the observed cations and
(Scheme 2).
The nitro derivatives
Ϫ
and
Ϫ were dissolved in
trifluoromethanesulfonic acid and the resulting solutions
were observed by NMR spectroscopy either at room tem-
perature or at 255 K. The starting material quickly disap-
peared to afford the only observable cations
Ϫ , respectively, which are characterized by a dithiocar- derivatives
Ϫ
and
Scheme 2. Formation of cations Ϫ and
and
Ϫ
from nitroethylene
Ϫ
Ϫ
1526
Eur. J. Org. Chem.
, 1525Ϫ1531

Synthesis of Six- to Nine-Membered Ring Oximinoorthodithiolactones
FULL PAPER
The addition mechanism at the CϪN triple bond of the
hydroxynitrilium ions implies that the phenyl group of the
attacking species and the OH of the formed hydroxyimin-
ium groups must adopt a cis configuration, as previously
observed[21Ϫ23] and also predicted on theoretical
grounds.[24,25] This mechanism explains why single isomers
of cations Ϫ and Ϫ are obtained, and why they must
have an (E) configuration.
The present study is an application of the usefulness of
arylalkyl-substituted nitroethylenedithiocetals in the field of
heterocyclic synthesis. Cyclic orthodithioester derivatives
such as isothiochromanones, 4,5-dihydrobenzo[d]thiepin-1-
one, 5,6-dihydro-4H-benzo[d]thiocin-1-one, and 8,9,10,11-
tetrahydro-7-thiabenzocyclononen-5-one oximes can be
prepared in good to fair yields in trifluoromethanesulfonic
acid, with the transient formation of conjugated hydroxyni-
trilium ions. Work is in progress in the field of heterocyclic
synthesis with other heteroatoms, and results will be pub-
lished in due course
The cations and can be trapped by methanol at low
temperature (Scheme 3) to afford, in fair to good yields, six-
to nine-membered ring cyclic orthodithioesters with an ox-
ime group in the benzylic position. These are derivatives of
isothiochromanones (
1-one ), 5,6-dihydro-4H-benzo[d]thiocin-1-one
) and 8,9,10,11-tetrahydro-7-thiabenzocyclononen-
5-one oximes ( and ).
,
), 4,5-dihydrobenzo[d]thiepin-
(
,
(
,
Melting points were determined with a Büchi
Melting Point B545 apparatus using capillary tubes (temperature
rate 2 °C/min) and were not corrected. Ϫ A Bruker DPX 300 spec-
1
trometer, equipped with a low-temperature probe, was used for H
and 13C NMR spectra recorded at 300.13 MHz and 75.47 MHz,
respectively. NMR spectra of cations were recorded in TFSA at low
temperature or at room temperature. Chemical shifts are reported
relative to Me4Si in [D4]methanol, contained in a sealed capillary
tube placed inside the NMR cell. The reproducibility of 13C NMR
shifts was about Ϯ 0.05 ppm, but from experiment to experiment
small-scale shifts were also observed depending on concentration,
temperature and on the NMR cell used. Chemical shift assignments
were made using DEPT 135 techniques and usual chemical shift
assignment rules. Ϫ Electron-impact ionization (70 eV) mass spec-
tra were obtained with a Finnigan Incos 500 instrument. Ϫ Mic-
roanalyses were performed with an N.A. 2000 Analyzer. Ϫ Flash
chromatography was achieved on silica gel (20 to 45 µm particle
size). Ϫ HPLC was used to check the purity or to identify the
various compounds described below. A Waters 600 pump equipped
with a Rheodyne 7125 injector valve (20 µL loop) and an Applied
Biosystem 785 A programmable or a Waters 486 UV detector, col-
umn 250 ϫ 4 mm I.D., 5 µm Spherisorb silica, were used. Triflic
acid came from Acros and was used without further purification.
No attempt was made to optimize the yields.
Scheme 3. Trapping of cations
Ϫ
and
Ϫ by methanol
The yields are reported in Table 1. Some difficulties were
experienced in reproducing the yields of the nine-membered
ring system where the yields are low, probably because in-
termolecular reactions are favored over cyclization, as is
generally observed in such large ring systems.[33]
Table 1. Yields of cyclic dithioorthoesters
Ϫ
and
Ϫ
Starting product
Product
Yield (%)
70
83
74
73
82
71
28
12
All these cyclic orthodithioesters are characterized by the
quaternary orthodithiolactone carbon atoms whose chem-
ical shifts increase steadily from δC ϭ 93.5 for the six-mem-
bered ring, to δC ϭ 101.3 for the nine-membered ring sys-
؊
PhCH2Br (1.46 mL, 12.3 mmol) was added over 5 min to a
stirred suspension of dipotassium salt
(2.62 g, 12.3 mmol) in
tem. The lactone methoxy group resonates at δC
50.5Ϫ52.0 and the oxime carbon atoms in the range δC
ϭ
ϭ
DMSO (50 mL) at room temp. The reaction was carried out under
N2 at room temp. for 17 h and then for 3 h at 50 °C. Iodomethane
(0.766 mL, 12.3 mmol) was then added all at once at room temp.
148.9Ϫ159.6, with more shielded values being observed for
the six-membered ring derivatives. The downfield shift of After 2 h at 40 °C, the reaction mixture was left for 14 h at room
temp. The reaction was monitored by TLC. At the end of the reac-
tion, CH2Cl2 (220 mL) was added to the DMSO solution. The
organic phase was washed with slightly acidified water (40 mL),
then with water (2 ϫ 20 mL) and finally with brine (30 mL). The
organic phase was dried with MgSO4, and the solvent was elimin-
ated under vacuum. The resulting caramel-like oil was purified by
the signal for the oxime carbon atom may be related to the
ring size, as was also observed in the cyclic ketone series.[35]
Only the (E)-configured oxime was observed, except in the
case of the seven-membered ring system. The (E) configura-
tion was confirmed by X-ray crystallographic analysis.[36]
These results are in full agreement with the expected mech-
anism of the reaction concerning the addition to a CϪN
triple bond of nitrile oxide in which the attacking group
and the O atom are in the cis configuration in the final
product.[24,25]
chromatography on silica gel to afford the nitro derivative
(elu-
ent CH2Cl2/AcOEt/hexanes,10:30:460), which was further crystal-
lized from MTBE/hexanes as pale yellow crystals (910 mg; 30.7%
yield). Ϫ M.p. 104Ϫ105 °C (MTBE). Ϫ IR (CHCl3): ν˜ ϭ 1271 (m),
1313 and 1317 (strong, NO2), 1525 (strong, NO2) 3025 and 3067
Eur. J. Org. Chem.
, 1525Ϫ1531
1527

J.-M. Coustard
FULL PAPER
1
(CH), 3142 (CH). Ϫ H NMR (CDCl3); solution of both (Z)/(E) and 126.1, 128.32, 128.36 and 128.4 (aromatic CH), 141.3 and
isomers in a 1:1 ratio at room temp.: δ ϭ 2.50 and 2.52 (s, 3 H, 141.5 (ipso-C), 164.0 and 164.2 [(RS)2Cϭ]. Ϫ MS (70 eV); m/z (%):
SCH3), 4.16 and 4.27 (s, 2 H, PhCH2S), 7.03 and 7.20 (s, 1 H,
vinylic H), 7.3Ϫ7.4 (m, 5 H, aromatic H). Ϫ 13C NMR (CDCl3); [Ph(CH2)4Sϩ], 131 (53), 104 (51) [C8H8ϩ], 91 (100) [C7H7ϩ]. Ϫ
both (Z) and (E) isomers: δ ϭ 15.2 and 17.8 (SϪCH3) 36.5 and C13H17NO2S2 (283.40): calcd. C 55.09, H 6.05, N 4.94, S 22.63;
237 (52) [Mϩ Ϫ NO2], 189 (11) [Mϩ Ϫ NO2 Ϫ CH3SH], 165 (25)
39.5 (PhϪCH2ϪS), 124.8 and 125.7 (ϭCHϪNO2), 128.1, 128.6, found C 55.06, H 6.01, N 4.85, S.22.33
128.9, 129.1, 129.2 and 129.4 (aromatic CH), 132.6 and 134.2 (ipso-
C), 163.2 and 163.4 [(RS)2Cϭ]. Ϫ MS (70 eV); m/z (%): 194 (7)
؊
[Mϩ Ϫ CH3S], 91 (100) [PhCH2ϩ]. Ϫ C10H11NO2S2 (241.32): calcd.
Dipotassium salt (2.63 g, 12.3 mmol) was dissolved in DMSO (35
mL) and a solution of Ph(CH2)2Br (4.46 g, 26.2 mmol) in DMSO
(10 mL) was added. Then the reaction medium was heated at 40
°C for 20 h under nitrogen. After cooling, CH2Cl2 was added (200
mL). The organic phase was washed with diluted HCl (2 ϫ 40 mL),
then with brine (2 ϫ 40 mL), and dried with MgSO4. A brown oil
was recovered after distillation of the solvent. Flash chromato-
graphy (AcOEt/Et2O/hexane, 5:3:42), followed by crystallization
C 49.77, H 4.59, N 5.80, S 26.57; found C 49.78, H 4.58, N 5.80,
S 26.55.
Yield 35%.
Ϫ M.p. 87Ϫ8 °C (acetonitrile/tert-butyl methyl ether). Ϫ IR
(CHCl3): ν˜ ϭ 1267, 1314 (strong, NO2), 1454, 1497, 1525 (strong,
1
NO2), 2856 (CH2), 2927 (CH2), 3015 and 3026 (CH). Ϫ H NMR
(CDCl3); solution of both (Z)/(E) isomers in an approximate 1:1
ratio at room temp. δ ϭ 2.43 and 2.45 (s, 2 ϫ 3 H, 2 ϫ SCH3),
2.96 (m, 2 H, CH2), 3.14 (t, J ϭ 7.2 Hz, 2 H, CH2 for one isomer)
and 3.22 (t, J ϭ 7.2 Hz, 2 H, CH2 for the other isomer), 7.00 (s, 1
H, vinylic H of the first isomer) and 7.10 (s, 1 H, vinylic H of the
second isomer), 7.21 (br. t, J ϭ 7 Hz, 6 H, aromatic H), 7.29 (br.
t, J ϭ 7 Hz, 4 H, aromatic-H). Ϫ 13C NMR [(Z) and (E) isomers
in CDCl3]: δ ϭ 15.3 and 17.6 (SCH3), 32.8 and 33.2 (CH2), 34.7
and 35.8 (CH2), 125.0 and 125.3 (ϭCHϪNO2), 126.8 and 127.1
(aromatic CH), 128.4 (aromatic CH), 128.6 and 128.7 (aromatic
CH), 138.2 and 139.0 (ipso-C), 163.6 and 163.9 [(RS)2ϾCϭ)]. Ϫ
MS (70 eV); m/z (%): 206 (15) [Mϩ Ϫ NO2], 104 (100). Ϫ
C11H13NO2S2 (255.34): calcd. C 51.74, H 5.13, N 5.49, S 25.11;
found C 51.55, H 5.11, N 5.44, S 24.99.
from MTBE afforded
(CHCl3) ν˜ ϭ 1263, 1311 and 1314 (strong, NO2), 1454, 1497, 1525
(strong, NO2), 2856 and 2933 (CH2), 2927 (CH2), 3014 and 3029
(CH), 3066 and 3089 (CH). Ϫ H NMR (CDCl3): δ ϭ 2.93 (m, 4
(2.75 g, 65%). Ϫ M.p. 95Ϫ96 °C. Ϫ IR
1
H, 2 CH2), 3.20 (m, 4 H, 2 CH2), 7.08 (s, 1 H, vinylic H), 7.15Ϫ7.35
(m, 10 H, aromatic H). Ϫ 13C NMR (CDCl3): δ ϭ 33.0, 33.3, 34.9
and 35.9 (CH2), 126.7 (ϭCHϪNO2), 126.8, 127.1, 128.4, 128.6 and
128.8 (aromatic CH), 138.1 and 139.0 (ipso-C), 162.0 [(RS)2Cϭ].
Ϫ MS (70 eV); m/z (%): 299 (18) [Mϩ Ϫ NO2], 194 (15) [Mϩ
Ϫ
NO2 Ϫ PhCH2CH2], 105 (100) [PhCH2CH2ϩ]. Ϫ C18H19NO2S2
(345.47): calcd. C 62.58, H 5.54, N 4.05, S 18.56; found C 62.53,
H 5.58, N 4.16, S 18.55.
Yield 69%. Ϫ M.p.
47Ϫ48 °C (MTBE). Ϫ IR (CHCl3) ν˜ ϭ 1270, 1311 and 1313 (both
strong, NO2), 1454, 1497, 1524 (strong, NO2), 2860 and 2941
A brown
oil that slowly crystallized (1.705 g, 53% yield). Further crystalliza-
tion afforded light yellow crystals. M.p. 78 °C (CH2Cl2/ether/pent-
ane). Ϫ IR (CHCl3) ν˜ ϭ 1268, 1307 and 1320 (strong, NO2), 1429,
1434, 1497, 1523 and 1525 (strong, NO2), 2859 and 2927 (CH2),
1
(CH2), 3014 and 3027 (aromatic CH), 3066 and 3087 (CH). Ϫ H
NMR (CDCl3): δ ϭ 2.03 (complex sext, J ഠ 7 Hz, 4 H, 2
CH2CH2CH2), 2.73 (t, J ϭ 7 Hz, 2 H, CH2S), 2.75 (t, J ϭ 7 Hz, 2
H, CH2S), 2.85 (t, J ϭ 7.3 Hz, 2 H, benzylic H), 3.00 (t, J ϭ 7 Hz,
2 H, benzylic H), 7.00 (s, 1 H, vinylic H), 7.10Ϫ7.45 (m, 10 H,
aromatic H). Ϫ 13C NMR (CDCl3): δ ϭ 28.6, 30.1, 30.9, 33.6, 34.5
and 34.6 (CH2), 125.4 (ϭCHϪNO2), 126.2, 126.4, 128.3, 128.4,
128.5 and 128.6 (aromatic CH), 139.9 and 140.4 (ipso-C), 162.8
[(RS)2Cϭ]. Ϫ MS (70 eV): m/z (%) ϭ 327 (25) [Mϩ Ϫ NO2], 265
(17) [Mϩ Ϫ PhC3H5], 222 (40) [Mϩ Ϫ PhCH2CH2CH2S], 175 (50),
151 (40) [PhC3H6ϩ],117 (60), 91 (100) [C7H7ϩ]. Ϫ C20H23NO2S2
(373.52): calcd. C 64.31, H 6.21, N 3.75, S 17.17; found C 64.24,
H 6.16, N 3.87, S 16.79.
1
3014 and 3026 (aromatic CH), 3065 and 3087 (CH). Ϫ H NMR
[CDCl3 solution of both (Z)/(E) isomers in an approximate 1:1 ra-
tio]: δ ϭ 2.01 (m, 4 H, CH2CH2CH2), 2.40 (s, 3 H, SCH3), 2.46 (s,
3 H, SCH3), 2.73 (m, 4 H, CH2S), 2.83 (t, J ϭ 7 Hz, 2 H, PhϪCH2)
and 2.98 (t, J ϭ 7 Hz, 2 H, PhϪCH2), 7.00 (s, 1 H, ϭCϪH) and
7.02 (s, 1 H, ϭCϪH), 7.21 (m, 6 H, aromatic H) and 7.28 (m, 4
H, aromatic H). Ϫ 13C NMR [CDCl3 solution of both (Z)/(E) iso-
mers in a roughly 1:1 ratio]: δ ϭ 15.0 and 17.3 (SCH3), 28.3, 29.7,
30.4, 33.3, 34.2 and 34.3 (CH2), 124.6 and 124.84 (ϭCHϪNO2),
125.89 and 124.84 (aromatic CH), 128.1 and 128.2 (aromatic CH),
128.1 and 128.3 (aromatic CH), 139.7 and 140.2 (ipso-C), 163.9
and164.0 [(RS)2Cϭ]. Ϫ MS (70 eV); m/z (%): 223 (35) [Mϩ
Ϫ
Viscous oil that crys-
tallized on standing. Yield 85%. Ϫ M.p. 45Ϫ7 °C. Ϫ IR (CHCl3)
ν˜ ϭ 1273, 1309 and 1317 (strong, NO2), 1454, 1496, 1523 (strong,
NO2), 2860 and 2939 (CH2), 3013 and 3027 (CH), 3064 and 3086
(CH). Ϫ 1H NMR (CDCl3): δ ϭ 1.76 (br. signal, 8 H, 2 ϫ
CH2CH2CH2CH2), 2.62 (t, J ϭ 6.9 Hz, 2 H, CH2ϪS) and 2.64 (t,
J ϭ 6.9 Hz, 2 H, CH2ϪS), 2.87 (t, J ϭ 6.75 Hz, 2 H, benzylic H),
NO2], 175 (50) [Mϩ Ϫ NO2 Ϫ CH3SH], 117 (65) [C9H9ϩ], 91 (100).
Ϫ C12H15NO2S2 (269.27): calcd. C 53.50, H 5.61, N 5.20, S 23.81;
found C 53.43, H 5.57, N 5.29, S 23.02.
Flash chro-
matography of the crude product (petroleum ether/ethyl acetate,
85:15) afforded
(2.22 g, 65%) as an oil that slowly crystallized.
Ϫ M.p. 46Ϫ49 °C (petroleum ether/ethyl acetate). Ϫ IR (CHCl3) 2.99 (t, J ϭ 6.75 Hz, 2 H, benzylic H), 7.02 (s, 1 H, vinylic H), 7.18
ν˜ ϭ1268, 1307 and 1320 (strong, NO2), 1430, 1453, 1497, 1525
(m, 6 H), 7.25 (m, 4 H). Ϫ 13C NMR (CDCl3): δ ϭ 26.7, 27.9,
(NO2), 2859 and 2929 (CH2), 3014 (aromatic CH), 3134 (CH). Ϫ 30.4, 30.4, 31.5, 34.4, 35.1 and 35.2 (all CH2), 125.3 (ϭCHϪNO2),
1H NMR (CDCl3) mixture of isomers: δ ϭ 1.71 (br. m, 4 H, CH2),
2.47 and 2.49 (s, 2.2:3 ratio, 3 H, SCH3), 2.64 (br. q, J ഠ 5 Hz, 2
125.9, 126.1, 128.3, 128.3, 128.3 and 128.4 (aromatic CH), 141.3
and 141.5 (ipso-C), 163.2 [(RS)2Cϭ]. Ϫ MS (70 eV); m/z (%): 402
H, benzylic CH2), 2.92 and 3.03 (t, J ϭ 7 Hz, 2 H, SϪCH2), 7.02 (0.001) [Mϩ ϩ 1], 384 (0.14), 371 (0.15), 355 (10) [Mϩ Ϫ NO2], 191
and 7.08 (s, in a 2.2:3 ratio, 1 H, vinylic H), 7.14 (m, 3 H, aromatic
(3) [Mϩ Ϫ NO2 Ϫ Ph(CH2)3CHϭS], 165 (5) [Ph(CH2)4Sϩ], 131
H), 7.25 (m, 2 H, aromatic H). Ϫ 13C NMR (CDCl3); mixture of (20), 104 (15) [C8H8ϩ], 91 (100) [C7H7ϩ]. Ϫ C22H27NO2S2 (401.58):
isomers: δ ϭ 15.3 and 17.6 (SCH3), 26.6, 27.9, 30.4, 30.5, 31.3,
34.4, 35.1 and 35.2 (CH2), 124.9 and 125.2 (ϭCHϪNO2), 125.9
calcd. C 65.80, H 6.78, N 3.49, S 15.97; found C 65.38, H 6.70, N
3.38, S 15.94.
1528
Eur. J. Org. Chem.
, 1525Ϫ1531

Synthesis of Six- to Nine-Membered Ring Oximinoorthodithiolactones
FULL PAPER
(weak, CϭNϪOH), 1827, 2935, 3007, 3276 (br. band, OH), 3564
1
(oxime, OH). Ϫ H NMR ([D6]DMSO/CDCl3): δ ϭ 2.07 (s, 3 H,
1H NMR (room temp./TMS, [D4]MeOH): δ ϭ 2.83 (s,
3 H, SϪCH3), 4.52 (s, 2 H, PhϪCH2ϪS), 7.19 (d, J ϭ 6.4 Hz, 1 o-
H), 7.26 (dd, J ϭ 7.8, 7.8 Hz, 1 H), 7.35 (dd, J ϭ 7.8, 7.8 Hz, 1
H), 7.79 (d, J ϭ 8 Hz, 1 o-H). Ϫ 13C NMR: δ ϭ 24.2 (SCH3), 40.7
(benzylic CH2), 117.7 (ipso-C), 129.1, 130.7 and 132.1 (aromatic
CH), 135.4 (ipso-C), 137.7 (aromatic CH), 149.2 (ϾCϭNϩϽ),
212.3 (ϾCϩ).
SCH3), 3.20 (s, 3 H, OCH3), 3.65 (d, J ϭ 15.9 Hz, 1 H, axial
benzylic H), 4.20 (d, J ϭ 15.9 Hz, 1 H, equatorial benzylic H),
7.15Ϫ7.35 (m, 3 H, aromatic H), 8.12 (dd, J ϭ 7.5 and 1.7 Hz, 1
H, o-H), 11.37 (s, 1 H, ϭNϪOH). Ϫ 13C NMR ([D6]DMSO/
CDCl3): δ ϭ 11.9 (SCH3), 30.2 (CH2), 51.5 (OCH3), 93.5 (orthodi-
thioester C), 125.9 and 127.1 (aromatic CH), 127.1 (ipso-C), 128.9
and 131.0 (aromatic CH), 135.6 (ipso-C), 148.9 (ϾCϭNϪOH). Ϫ
MS (70 eV); m/z (%): 224 (1) [Mϩ Ϫ CH3O], 208 (70) [Mϩ
Ϫ
1H NMR (room temp.): δ ϭ 1.89 (br. s, 2 H, CH2Ͻ),
2.50 (br. s, 2 H, benzylic H), 2.89 (br. s, 3 H, SCH3), 3.54 (br. s, 2
H, SCH2), 6.91 (d, J ϭ 7.7 Hz, 1 H), 6.97 (t, J ϭ 7.7 Hz, 1 H),
7.16 (t, J ϭ 7.7 Hz, 1 H), 7.21 (d, J ϭ 8.5 Hz, 1 H). Ϫ 13C NMR:
δ ϭ 23.7 (SCH3), 31.5 (CH2), 36.5 (CH2), 118.1 (ipso-C), 128.3,
129.1 and 132.5 (aromatic CH), 136.9 (ipso-C), 138.2 (aromatic
CH), 158.3 (ϾCϭNϩϽ), 220.1 (CϩϽ).
CH3S], 176 (5) [Mϩ Ϫ CH3S Ϫ CH3OH], 148 (20), 134 (32), 116
(70) [C4H6ONSϩ], 89 (65) [C3H5OSϩ], 75 (100) [C2H3OSϩ]. Ϫ
C11H13NO2S2 (255.34): calcd. C 51.74, H 5.13, N 5.49, S 25.11;
found C 51.64, H 5.16, N 5.35, S 24.36.
d
From nitroethylene derivative (312 mg, 1.22 mmol)
in TFSA (4.0 mL, 45 mmol) at room temp. for 1 h. Flash chroma-
tography (CH2Cl2/AcOEt/iPrOH, 95:5:0.5) afforded compound
(244 mg, 74%). Ϫ M.p. 181Ϫ3 °C (dec.). Ϫ 1H NMR
([D6]DMSO/CDCl3): δ ϭ 2.04 (s, SMe), 2.70 (m, 1 H), 3.05 (m, 3
H), 3.35 (s, 3 H, OMe), 7.14 (m, 2 H), 7.24 (m, 2 H), 11.08 (s, 1
H, ϭNϪOH). Ϫ 13C NMR ([D6]DMSO/CDCl3): δ ϭ 12.1 (SCH3),
27.4 (br. and weak signal for both CH2 groups), 50.8 (OCH3), 96.6
(orthodithioester C), 125.3, 128.3, 129.2 and 129.8 (aromatic CH),
132.9 (ipso-C), 136.5 (ipso-C), 156.6 (ϾCϭN). Ϫ MS (70 eV); m/z
(%): 269 (Ͻ 1) [Mϩ], 252 (5) [Mϩ Ϫ OH], 238 (2) [Mϩ Ϫ OCH3],
222 (100) [Mϩ Ϫ SCH3], 130 (20), 116 (20) [C4H6ONSϩ], 89 (17)
[C3H5OSϩ], 75 (58) [C2H5OSϩ]. Ϫ C12H15NO2S2 (269.38): calcd.
C 53.51, H 5.61, N 5.20, S 23.81; found C 53.44, H 5.44, N 5.39,
S 22.92.
1H NMR (255 K): δ ϭ 1.85 (br. s, 2 H, CH2), 2.47 (br.
s, 2 H, CH2), 2.86 (s, 3 H, SϪCH3), 3.51 (br. s, 2 H, CH2), 7.01
(m, 1 H), 7.20 (br. s, 1 H), 7.56 (br. s, 1 H), 6.92 (m, 1 H). Ϫ 13C
NMR: δ ϭ 26.2 (SϪCH3), 29.6, 33.4 and 44.6 (CH2), 122.5, 129.5
(ϭCϪH), 134.5, 140.0, 158.5 (ϾCϭNϩϽ), 220.1 (CϩϽ).
1H NMR (254 K): δ ϭ 4.31 (s, 2 H, CH2), 4.37 (s, 2 H,
CH2), 6.6 to 6.9 (br. m, 5 H, Ph), 7.17 (d, J ϭ 7.6 Hz, 1 H, ortho-
H), 7.21 (dd, J ϭ 7.6 and 8 Hz, 1 H), 7.34 (dd, J ϭ 7.7 and 7.7 Hz,
1 H), 7.77 (d, J ϭ 8 Hz, 1 H, ortho-H). Ϫ 13C NMR (room temp.):
δ ϭ 41.0 (benzylic C), 48.4, 117.7 (ipso-C), 125.6, 129.0 (br. s, aro-
matic CH), 129.4 (aromatic CH), 129.6, 130.4, 135.3 (ipso-C), 148.2
(ϾCϭNϩϽ), 209.0 (ϾCϩ).
1H NMR (255 K): δ ϭ 2.62 (m, 2 H, CH2CH2CH2),
2.82 (m, 2 H, CH2CH2CH2), 3.19 (br. d, 1 H), 3.40 (m, 2 H), 3.65
(t, J ϭ 14 Hz, 1 H, CH2S), 6.56 (m, 5 H), 6.92 (d, J ϭ 7.8 Hz, 1
H), 6.98 (t, J ϭ 7.7 Hz, 1 H), 7.16 (d, J ϭ 7.6 Hz, 1 H) 7.19 (t,
J ϭ 7.8 Hz, 2 H), 12.70 (v br. s, ϭNHϩϪOH). Ϫ 13C NMR: δ ϭ
32.3, 32.5, 37.2, 46.8 (br. s), 119.1, 128.8, 129.2, 129.4, 129.9, 130.0,
133.5, 136.2, 137.8, 139.3, 159.0 (ϾCϭNϩϽ), 216.6 (ϾCϩ).
H
d
From nitroethylene derivative
(241 mg,
0.896 mmol) in TFSA (4.9 mL, 55 mmol) for 2 h at 0Ϫ5 °C. Flash
chromatography (CH2Cl2/EtOH, 99:1) afforded compound
(184 mg, 82%) as white crystals. Ϫ M.p. 191Ϫ193 °C (dec.). Ϫ H
1
NMR ([D6]DMSO/CDCl3, 4:1) mixture of isomers in 3:2 ratio
(main signal with *): δ ϭ 1.5Ϫ1.9 (m, 1.7 H), 1.9Ϫ2.1 (m, 0.3 H),
2.03 and 2.05* (s, 3 H, SCH3), 2.15Ϫ2.3 (m, 0.7 H), 2.4Ϫ2.8 (m,
3.4 H), 3.38* and 3.40 (s, OCH3), 6.88* and 7.03 (d, J ϭ 7.2 Hz
and J ϭ 7.0 Hz, 1 H, ortho-H), 7.1Ϫ7.3 (m, 3 H, aromatic H),
11.13 and 11.17* (s, 1 H, NϪOH). Ϫ 13C NMR ([D6]DMSO/
CDCl3) (two isomers, main signal with *): δ ϭ 11.4 and 12.4*
(SCH3), 26.5 and 29.5* (CH2S), 30.5 and 31.1* (benzylic CH2),
32.2* and 34.1 (CH2ϪCH2ϪCH2), 50.6 and 50.4* (OCH3), 99.2
and 99.9* (dithioorthoester C), 124.8 and 125.3* (aromatic CH),
127.5* and 127.7 (aromatic CH), 128.3* and 128.4 (aromatic CH),
128.6 (aromatic CH), 134.1 and 134.3* (ipso-C), 137.9 and 140.6*
(ipso-C), 156.1 and 157.3* (ϾCϭNϪOH). Ϫ MS (70 eV); m/z (%):
283 (2) [Mϩ], 266 (9) [Mϩ Ϫ OH], 252 (55) [Mϩ Ϫ OCH3], 236
(100) [Mϩ Ϫ SCH3], 204 (20) [Mϩ Ϫ SCH3 Ϫ CH3OH], 116 (50)
[C8H6N]. Ϫ C13H17NO2S2 (283.40): calcd. C 55.10, H 6.05, N 4.94,
S 22.63; found C 55.57, H 6.20, N 5.31, S 22.43.
1H NMR (255 K):
δ ϭ 1.80 (br. s, 4 H, 2
CH2ϪCH2ϪCH2), 2.22 (br. s, 2 H, benzylic H), 2.30 (br. s, 2 H
benzylic H), 3.21 (br. s, 2 H, CH2S), 3.33 (br. s, 2 H, CH2S), 6.12
(br. s, 1 H, aromatic H), 6.33 (br. s, 2 H, aromatic H), 6.50 (br. s,
2 H, aromatic H), 6.96 (br. s, 2 H, aromatic H), 7.23 (br. s, 1 H,
aromatic H), 7.60 (br. s, 1 H, aromatic H). Ϫ 13C NMR: δ ϭ 27.3,
29.2, 33.0, 34.4, 43.1 and 45.0 (CH2ϪS), 122.8, 128.0, 128.7, 129.7,
130.0, 133.5, 134.8, 139.5, 143.9, 155.7 (ϾCϭNϩϽ), 214.3 (CϩϽ).
Mostly broadened signals and slow decomposition at 255 K.
؊
؊
Nitroethylene derivative
(322 mg, 1.33 mmol) was dissolved in TFSA (5.0 mL, 56 mmol)
at a temperature between Ϫ10 and ϩ2 °C, and left for 40 min. The
solution was quenched with MeOH/CH2Cl2 (18:52, 70 mL) at a
temperature between Ϫ60 and Ϫ80 °C, and then CH2Cl2 (100 mL)
was added. At a temperature between Ϫ10 and 0 °C, the resulting
organic phase was washed with water (30 mL), then brine (20 mL),
From nitroethylene derivative
and finally with brine containing NaHCO3. The organic phase was (517 mg, 1.83 mmol) in TFSA (9 mL, 101 mmol) for 30 min at 0Ϫ5
dried with MgSO4 and the solvent was evaporated under vacuum
to afford a crystallized product. Flash chromatography led to the
recovery of some starting material (petroleum ether/AcOEt, 9:1, tion from AcOEt/hexane. Ϫ M.p. 173Ϫ174 °C (dec.). Ϫ H NMR
°C. Flash chromatography (CH2Cl2/EtOH, 98:2) afforded com-
pound (152 mg, 28%) as light yellow crystals after crystalliza-
1
9 mg, 2.7%). Further elution (petroleum ether/AcOEt/CH2Cl2,
40:7:3) afforded the cyclic derivative (236 mg; 70%), which was
further crystallized from AcOEt as white crystals. Ϫ M.p. 134Ϫ136
(CDCl3), mixture of two isomers (1:7 ratio): δ ϭ 1.28 (m, 2 H) and
1.86 (m, 4 H), 2.10 (CH3S) and 2.69 (m, 4 H), 3.48 (CH3O), 7.26
(d, J ϭ 7.4 Hz, 2 H), 7.35 (d, J ϭ 7.4 Hz, 1 H), 7.47 (d, J ϭ 7.4 Hz,
°C (dec.). Ϫ IR (CHCl3) ν˜ ϭ 940, 1059, 2860 1454, 1495, 1602 1 H), 9.02, (s, ϭNϪOH). Ϫ 13C NMR (CDCl3): δ ϭ 12.2 (SCH3),
Eur. J. Org. Chem.
, 1525Ϫ1531
1529

J.-M. Coustard
FULL PAPER
25.1, 27.6, 27.8 and 28.6 (CH2), 50.7 (CH3O), 98.7 (orthodithio-
C21H25NO2S2 (387.55): calcd. C 65.08, H 6.50, N 3.61, S 16.54;
ester C), 125.3, 127.6, 128.7 and 129.1 (aromatic CH), 131.8 and found C 64.92, H 6.42, N 3.69, S 16.46.
141.3 (ipso-C), 156.5 (ϾCϭNϪOH). Ϫ MS (70 eV); m/z (%): 280
(2.8) [Mϩ Ϫ OH], 250 (28) [Mϩ Ϫ SCH3], 218 (30) [Mϩ Ϫ CH3S
From nitroethylene derivative
(366 mg, 0.913 mmol) in triflic acid (4.6 mL, 51.5 mmol) for
10 min at 0Ϫ5 °C. Flash chromatography (hexane/ethyl acetate,
Ϫ CH3OH], 201 (7) [Mϩ Ϫ CH3S Ϫ CH3OH Ϫ OH], 186 (14), 116
(45) [C4H6ONSϩ], 75 (100) [C2H3OSϩ]. Ϫ C14H19NO2S2 (297.43):
calcd. C 56.53, H 6.44, N 4.71, S 21.56; found C 56.68, H 6.59, N
4.97, S 20.98.
15:85) afforded compound
(54 mg, 12%). Ϫ M.p. 144 °C (pent-
1
ane/CH2Cl2/MTBE). Ϫ H NMR (CDCl3): δ ϭ 1.5Ϫ2.0 (m, 8 H),
2.5Ϫ2.9 (m, 6 H), 3.49 (s, 3 H, OCH3), 7.0Ϫ7.5 (m, 9 H), 9.74 (s, ϭ
NϪOH). Ϫ 13C NMR (CDCl3): δ ϭ 28.1, 29.4, 30.0, 30.4, 30.9,
32.6, 35.3, 35.4 (all CH2), 52.0 (OCH3), 101.3 (orthodithioester C),
125.7, 125.8, 128.3, 128.3, 128.4, 141.95 and 141.97 (aromatic C),
152.6 (ϾCϭNϪOH). A slight isomerization occurred during 13C
NMR analysis [examples of new signals: δ ϭ 50.8 (OCH3), 141.1
(aromatic C), 156.9 (ϾCϭNϪOH)]. No reaction at Ϫ10 °C even
after 30 min. Ϫ MS (70 eV); m/z (%): 250 (98) [Mϩ Ϫ Ph(CH2)4S],
From nitroethylene derivative (343 mg, 1.08 mmol) in TFSA (5.0
mL, 56 mmol) at a temperature between Ϫ9 and Ϫ2 °C for 30 min.
Flash chromatography (petroleum ether/AcOEt, 9:1) afforded
starting material
(11.4 mg, 11.4%), and then compound
(298 mg, 83.3%) as white crystals. Ϫ M.p. 136Ϫ8 °C (dec.) from
1
pentane/MTBE. Ϫ H NMR ([D6]DMSO/CDCl3): δ ϭ 3.34 (s, 3
H, OMe), 3.67 (d, J ϭ 16 Hz, 1 H, axial benzylic H), 3.83 (d, J ϭ
12.6 Hz, 1 H, PhϪCHH), 3.86 (d, J ϭ 12.6 Hz, 1 H, PhϪCHH),
4.21 (d, J ϭ 16 Hz, 1 H, equatorial benzylic H), 7.20Ϫ7.30 (m, 8
H, aromatic H), 8.05 (dd, J ϭ 9 Hz, J ϭ 1.4 Hz, 1 H, o-H), 11.44
(s, 1 H, ϭNϪOH). Ϫ 13C NMR ([D6]DMSO/CDCl3): δ ϭ 30.2
and 33.9 (CH2), 51.8 (OCH3), 94.4 (orthodithioester C), 125.9,
126.7 and 127.0 (aromatic CH), 127.2 (ipso-C), 128.3, 128.9, 129.0
and 131.0 (aromatic CH), 135.7 (ipso-C), 137.6 (ipso-C), 148.9
(ϾCϭNϪOH). Ϫ MS (70 eV); m/z (%): 208 (38) [Mϩ Ϫ PhCH2S],
176 (3) [Mϩ Ϫ PhCH2S Ϫ CH3OH], 148 (10), 134 (24), 116 (25),
91 (100) (C7H7ϩ). Ϫ C17H17NO2S2 (331.44): calcd. C 61.60, H 5.17,
N 4.23, S 19.35; found C 61.56, H 5.19, N 4.20, S 19.23.
190 (35), 132 (75), 156 (40), 116 (100) [C4H6ONSϩ].
Ϫ
C23H29NO2S2 (415.60) calcd. C 66.47, H 7.03, N 3.37, S 15.43;
found C 66.41, H 7.03, N 3.31, S 14.71.
We wish to thank Janie Joffre for low-resolution mass spectrometry
and Sophie Schneider for elemental analysis. Thanks are also due
to CNRS for financial support.
[1]
A. G. M. Barrett, Chem. Soc. Rev.
, 20, 95Ϫ127.
J.-Y. Liu, M.-C. Yan, W.-W. Lin, L.-Y. Wang, C.-F. Yao, J.
Chem. Soc., Perkin Trans. 1 , 1215Ϫ1279.
[2]
[3]
[4]
[d]
J. P. Adams, D. S. Box, J. Chem. Soc., Perkin Trans. 1.
749Ϫ764 and references therein.
C. Schmitz, J. N. Harvey, H. G. Viehe, Bull. Soc. Chim. Belg.
, 103, 105Ϫ114.
A. Padwa, A. G. Waterson, J. Org. Chem.
A. Padwa, D. E. Gunn, M. H. Osterhout, Synthesis
1353Ϫ1377 and references therein.
B. M. Trost, E. Murayama, J. Am. Chem. Soc.
6529Ϫ6530.
B. M. Dilworth, M. A McKervey, Tetrahedron
3731Ϫ3752.
,
From nitroethylene derivative
(297 mg,
0.861 mmol) in TFSA (5.0 mL, 56 mmol) at 0Ϫ5 °C for 6 min.
Flash chromatography (CH2Cl2/AcOEt, 9:1) afforded compound
(222 mg, 72%). Ϫ M.p. 119Ϫ120 °C (white prisms from ether/
[5]
[6]
, 65, 235Ϫ244.
1
,
, 103,
, 42,
pentane). Ϫ H NMR (CDCl3): δ ϭ 2.3Ϫ3.4 (complex m, 8 H, 4
CH2), 3.46 (br. s, 3 H, OCH3), 7.0Ϫ7.5 (m, 9 H, aromatic H), 9.44
(br. s, 1 H, ϭNϪOH). Ϫ 13C NMR (CDCl3): δ ϭ 26.9 (CH2), 31.4
(CH2), 33.1 (CH2), 35.1 (CH2), 51.4 (OCH3), 97.7 (orthodithioester
C), 125.7 (aromatic CH) 126.4, 128.46 and 128.52 (aromatic CH),
129.2 (aromatic CH), 129.6 and 129.8 (aromatic CH), 131.8 and
136.2 (ipso-C), 140.3 (ipso-C), 157.2 (oxime C). Ϫ MS (70 eV); m/
z (%): 359 (Ͻ 1) [Mϩ], 342 (5) [Mϩ Ϫ OH], 328 (2) [Mϩ Ϫ OCH3],
222 (100) [Mϩ Ϫ PhCH2CH2S], 130 (42), 105 (65) [C8H9ϩ], 91 (82)
[C7H7ϩ]. Ϫ C19H21NO2S2 (359.50): calcd. C 63.48, H 5.89, N 3.90,
S 17.84; found C 63.58, H 5.98, N 4.07, S 17.58.
[7]
[8]
[9]
G. A. Olah, Q. Wang, G. Neyer, Synthesis
, 276Ϫ278.
[10]
[11]
[12]
S. Rajappa, Tetrahedron
S. Rajappa, Tetrahedron
, 55, 7065Ϫ7114.
, 37, 1453Ϫ1480.
Z. F. Pavlova, E. S. Lipina, V. V. Perekalin, Sulfur Report
16, 149Ϫ172.
P. A. Harris, A. Jackson, J. A. Joule, Synthesis
769Ϫ772.
K. V. Reddy, S. Rajappa, Heterocycles
T. I. Reddy, B. M. Bhawal, S. Rajappa, Tetrahedron
2101Ϫ2108.
A. V. N. Reddy, S. N. Maiti, I. P. Singh, R. G. Micetich, Synth.
Commun. , 19, 3021Ϫ3025.
Y. Tominaga, K. Komiya, S. Kataoka, Y. Shigemitsu, T. Hir-
ota, K. Sasaki, Heterocycles , 48, 1985Ϫ1988.
,
[13]
, 8,
[14]
[15]
, 37, 347Ϫ354.
, 49,
H
-
[d]
From nitroethylene derivative
[16]
[17]
[18]
(239 mg, 0.641 mmol) in TFSA (5 mL, 56 mmol) at 0Ϫ5 °C for
20 min. Flash chromatography (CH2Cl2/EtOH, 99:1) afforded
1
(163 mg, 71%) as white crystals. Ϫ M.p. 147Ϫ148 °C. Ϫ H NMR
([D6]DMSO/CDCl3, 4:1, mixture of two isomers in a 45:55 ratio,
major isomer *): δ ϭ 1.8Ϫ2.3 (m, 5 H, CH2), 2.5Ϫ2.8 (m, 7 H,
CH2), 3.28* and 3.40 (s, 3 H, OCH3), 6.80 and 7.03* (d, J ϭ 7.2 Hz
and d, J ϭ 7.2 Hz, 1 H, ortho-H), 7.1 to 7.3 (m, 9 H, aromatic H),
11.120* and 11.125 (s, 1 H, ϭNϪOH). Ϫ 13C NMR (CDCl3, mix-
ture of two isomers): δ ϭ 26.0, 29.1, 29.6, 30.1, 30.2, 30.7, 31.1,
32.7, 34.4, 35.3, 35.33, 50.5 and 51.2* (OCH3), 98.4 and 98.8* (or-
thodithioester C), 125.3, 125.6, 125.9, 126.0, 127.5, 128.0, 128.4,
128.4, 128.5, 128.8, 129.0, 129.3, 132.8, 133.5, 137.6, 140.7, 141.1,
141.4, 158.0* and 159.6 (ϾCϭNϪOH). Ϫ MS (70 eV); m/z (%):
N. Terang, B. K. Mehta, H. Ila, H. Junpappa, Tetrahedron
, 54, 12973Ϫ12984.
[19]
[20]
W.-L. Cheng, T.-Y. Luh, J. Chem. Soc.
M. Baudry, M.-N. Bouchu, G. Descotes, J.-P. Praly, F. Bellamy,
Carbohydratr. Res. , 282, 237Ϫ246.
, 1392Ϫ1393.
[21]
[22]
[23]
[24]
[25]
J.-M. Coustard, Tetrahedron
J.-M. Coustard, Tetrahedron
J.-M. Coustard, Tetrahedron
A. F. Hegarty, Acc. Chem. Res.
, 51, 10929Ϫ10940.
, 52, 9509Ϫ9520.
, 55, 5809Ϫ5820.
, 13, 448Ϫ454.
M. T. Nguyen, S. Malone, A. F. Hegarty, T. I. Williams, J. Org.
Chem. , 56, 3683Ϫ3687.
A. Cousson, J.-M. Coustard, Tetrahedron
6523Ϫ6528.
A. Cousson, J.-M. Coustard, Zr. Krist. NCS
469Ϫ470.
[26]
[27]
,
54,
370 (3) [Mϩ Ϫ OH], 236 (95) [Mϩ Ϫ Ph(CH2)3S], 204 (18) [Mϩ
Ϫ
Ph(CH2)3S Ϫ CH3OH], 187 (15) [Mϩ Ϫ Ph(CH2)3S Ϫ CH3OH Ϫ
, 214,
OH], 143 (25), 117 (55), 91 (100) [C7H7ϩ], 75 (72) [C2H3OSϩ]. Ϫ
1530
Eur. J. Org. Chem.
, 1525Ϫ1531

Synthesis of Six- to Nine-Membered Ring Oximinoorthodithiolactones
FULL PAPER
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