Reactivity of the lithium anion of the (S,S)-bis-p-tolylsulfinyl methane. A versatile synthesis of enantiopure alkylidene 1,1-bis-tolysulfoxides

Article abstract of DOI:10.1016/S0022-328X(01)01210-4

We describe herein a new synthesis of enantiopure alkylidene 1,1-bis-p-tolyl-sulfoxides (5), based on a two-steps sequence. The first one involves the alkylation of the lithium anion of the (S,S)-bis-p-tolylsulfinylmethane (1) with aldehydes. The second one consists in a mild dehydration of the sulfinyl alcohols 3 and 4 with the morpho CDI reagent. Some features (reactivity, diastereoselectivity) of the alkylation reaction are discussed.

Full text of DOI:10.1016/S0022-328X(01)01210-4

Journal of Organometallic Chemistry 643–644 (2002) 130–135
www.elsevier.com/locate/jorganchem
Reactivity of the lithium anion of the (S,S)-bis-p-tolylsulfinyl
methane. A versatile synthesis of enantiopure alkylidene
1,1-bis-p-tolylsulfoxides
Be´ne´dicte Delouvrie´, Francisco Na´jera, Louis Fensterbank *, Max Malacria *
Laboratoire de Chimie Organique de Synthe`se, Uni6ersite´ P. et M. Curie, associe´ au CNRS, Tour 44-54, B. 229, 4, place Jussieu,
75252 Paris Cedex 05, France
Received 19 June 2001; accepted 31 August 2001
Abstract
We describe herein a new synthesis of enantiopure alkylidene 1,1-bis-p-tolyl-sulfoxides (5), based on a two-steps sequence. The
first one involves the alkylation of the lithium anion of the (S,S)-bis-p-tolylsulfinylmethane (1) with aldehydes. The second one
consists in a mild dehydration of the sulfinyl alcohols 3 and 4 with the morpho CDI reagent. Some features (reactivity,
diastereoselectivity) of the alkylation reaction are discussed. © 2002 Elsevier Science B.V. All rights reserved.
Keywords: Sulfoxides; Diastereoselectivity; Asymmetric synthesis; Carbanions; Condensation
tolylsulfinylmethane (1) with diverse carbonyl deriva-
tives that gave bis-sulfinylalcohols, showed that with
a,b-unsaturated aldehydes, the corresponding bis-sulfi-
nyldienes were directly obtained in good yields [5].
Another report by Carretero [6] mentions the synthesis
of the (S,S)-1,1-bis-ethoxycarbonyl-2,2-bis-p-tolylsulfi-
nyl ethene, in a two-steps sequence involving first a
quantitative condensation with oxomalonate, followed
by a dehydration with DEAD.
1. Introduction
Enantiopure alkylidene 1,1-bis-p-tolyl-sulfoxides (5)
are attractive molecules because they possess an elec-
tron-withdrawing moiety exhibiting a local C2-symme-
try, which should garantee high reactivities and
diastereoselectivities in cycloadditions or conjugate ad-
ditions [1]. This has been recently exploited by Aggar-
wal who illustrated the concept of chiral ketene
equivalent with alkylidene cyclic disulfoxides such as
trans-1,3-dithiane [2] or dithiolane [3] 1,3-dioxides ob-
tained through asymmetric oxidation. However, acyclic
analogs, such as 1,1-bis-aryl substrates, which could
present some interesting complementary reactivity have
witnessed less interest. Although the simplest term of 5
with R=H is a known compound, reported by
Koizumi in 1986 [4], curiously and to the best of our
knowledge, substituted derivatives of 5 with R=alkyl
or aryl are fairly unknown compounds. Only two spe-
cial cases have been reported. Solladie´, while focusing
on the condensation of the lithium anion of (S,S)-bis-p-
2. Results and discussion
In that context, we wanted to develop a general
synthesis of the alkylidene disulfoxides 5, and also at
the occasion reexamine the diastereoselectivity of the
formation of the diastereomeric bis-sulfinyl alcohols 3
and 4 with simple alkylaldehydes (Scheme 1). Dis-
suaded by a Knoevenagel approch [7], we focussed on a
method involving a preformation of the anion of 1 [8].
This was accomplished with 1.1 equivalents of n-BuLi
at −40 °C. After 1 h at that temperature, 1.5 equiva-
lents of the carbonyl derivative 2 were added at
−78 °C. Although the alkylation appeared relatively
immediate, we raised the temperature of the reaction
medium to −25 °C to garantee an almost complete
* Corresponding authors. Fax: +33-1-44277360 (M.M.).
E-mail addresses: fensterb@ccr.jussieu.fr (L. Fensterbank),
malacria@ccr.jussieu.fr (M. Malacria).
0022-328X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)01210-4

B. Delou6rie´ et al. / Journal of Organometallic Chemistry 643–644 (2002) 130–135
131
Scheme 1.
Table 1
To our surprise, this alkylation reaction proved to be
fairly diastereoselective even for simple alkyl aldehydes,
and even completely diastereoselective with pivalalde-
hyde (entry 3). This is interesting in view of the results
of Aggarwal [10,11] with cyclic disulfoxides, and of
Solladie´ [5] with 1 who generally obtained high selectiv-
ities only for aromatic aldehydes. More precisely, for
hexanal and iso-butyraldehyde 2b and at −78 °C,
Solladie´ reported diastereomeric excesses of 20 and
10%, respectively. In contrast, while raising the temper-
ature to −25 °C and with aldehydes 2a and 2b, we
observed selectivities of 64 and 62% (Table 1, entries 1
and 2). We suspected the reaction to be reversible in
our conditions and to result in a thermodynamic ratio
of products. However, this was refuted by two findings.
When we stopped the reaction with 2a at −78 °C after
15 min, we observed on the crude NMR spectrum the
following ratio: 1–3a–4a, 31:56:13, demonstrating that
the diastereoselectivity was essentially identical at lower
temperature. Moreover, when minor diastereomer 4a
was treated at −78 °C with one equivalent of n-BuLi
and upon raising the temperature to −25 °C and
quenching at that temperature, we recovered unaltered
4a, accompanied by minor amounts of 5a (B5%).
Thus, no equilibration seems to intervene, and further
work will be necessary to address these discrepancies. It
should be noted also that the same type of diastereose-
lectivity was observed when sodium hydride was used
instead of butyllithium: 3a–4a, 89:11 (total yield 68%).
In all these reactions, as for Solladie´, the main
diastereomer corresponds to the (S,S,S)-3. This was
established by correlation with Solladie´’s data or by
chemical derivatization as for major diastereomer 3b
(Scheme 2). A Pummerer reaction [12], followed by a
LAH reduction of the intermediate thioester 6 provided
the known (S)-(+)-3-methyl-1,2-butanediol (7)
([h]2D0+9.0 (c 3.0, CHCl3), lit. [13] [h]2D0+11.7 (neat)).
This sequence also augurs well for the synthesis of
enantiopur a-hydroxy acids if a non-racemizing sapon-
ification of thioesters like 6 is found out.
Formation of the alcohols 3 and 4
Scheme 2.
conversion. We have noticed that above that tempera-
ture, dehydration occurs [9]. In that basic reaction
medium, isomerization to the allylsulfoxide (except for
R=Ph or t-Bu) followed by a [2,3]-Evans–Mislow
rearrangement gives (E)-g-hydroxyvinylsulfoxides [7].
After quenching at −25 °C and usual treatment, good
yields of alcohols 3 and 4 (70–89%) were obtained. In
the case of benzaldehyde (entry 4), hexamethylphos-
phorous triamide HMPT (1.5 equivalents) had to be
added in the reaction to observe a decent conversion. It
should also be noted that after the chromatography
process, in addition to the alcohols 3 and 4, dehydra-
tion adducts 5 were observed in a slight extent (ca. 5%)
for aldehydes 2a–d and 2f, and that for acrolein 2e
(entry 5), only bis-sulfinyldiene 5e was obtained.
Scheme 3.

132
B. Delou6rie´ et al. / Journal of Organometallic Chemistry 643–644 (2002) 130–135
(u=254 nm) or a p-anisaldehyde solution. Flash
column chromatography has been performed with Sil-
ica gel Merck Geduran SI (40–63 nm). Solvents were
systematically distilled prior to be used. The aldehydes
were dried over CaSO4 and distilled. IR spectra were
recorded on a Perkin–Elmer 1420 spectrometer. 1H-
and 13C-NMR spectra were recorded at room tempera-
ture (r.t.), either at 200 and 50 MHz on a AC200
Bruker spectrometer, or at 400 and 100 MHz, respec-
tively on an ARX400 Bruker spectrometer. Shifts are
given in ppm and referenced from the solvent residual
signal (7.26 ppm for CDCl3) for proton NMR. For
carbon NMR, shifts are referenced from the solvent
central peak (77.0 ppm for CDCl3). Coupling constants
(J) are given in Hertz (Hz). The letters m, s, d, t, q,
hept mean, respectively multiplet, singulet, doblet,
triplet, quadruplet, heptuplet. Elemental analysis were
performed by the Service Re´gional de Microanalyse de
l’Universite´ Pierre et Marie Curie. Melting points were
obtained on a Reichert apparatus and are uncorrected.
Chiral GC was run using a column CP-Chirasil-DEX
CB (25 m), FID and N2 as carrier gas.
Scheme 4.
Table 2
Dehydration of alcohols 3 and 4
Entry
Alcohols 3+4, R
Product 5, yield (%) a
1
2
3
4
5
3a+4a, n-Bu
3b+4b, i-Pr
3c, t-Bu
3d+4d, Ph
3f+4f
5a, quant.
5b (90)
5c (82)
5d (85)
5f (65)
a All reactions are run with 1.2–2 equivalents of 8 and CuCl2
catalyst at 60 °C in MeCN for 2–3 h under N2.
One could propose the following model of
diastereoselection, as depicted on Scheme 3. The most
favorable approach involves chelated transition state A
on which non-bonded interactions between the p-tolyl
groups of 1 and the R group of aldehyde 2 are mini-
mized compared to B [14]. Further refinements will be
required to determine how the use of a sodium base
and the use of HMPT fit with this proposal.
Finally, a variety of reaction conditions were tested
for a mild dehydration of alcohols 3 and 4. The cerium-
based reagent for the dehydration of aldol adducts [15],
as well as the Burgess reagent [16,17] did not give
satisfactory results. We found the morpho CDI reagent
8, previously used by Aggarwal [18], quite versatile and
convenient for that transformation, as illustrated by the
good yields of adducts 5 (Scheme 4; Table 2).
4.1. General procedure for the synthesis of bis-sulfinyl
alcohols 3 and 4
To a solution of 1.75 g (6 mmol, one equivalent) of
(S,S)-bis-p-tolylsulfinylmethane (1) [8] (previously dried
at 70 °C under vacuum) in THF (25 ml) were added, at
−40 °C, n-BuLi in hexanes (7.2 mmol, 1.2 equivalents)
and the solution was stirred at −40 °C for 1 h. Then,
the reaction mixture was cooled to −78 °C and the
freshly distilled aldehyde was added neat (1.5–2.0
equivalents). The reaction was stirred at this tempera-
ture for half an hour, at −40 °C for 1 h and finally at
−25 °C for an additional hour. Then, it was quenched
with an (aq.) saturated NH4Cl solution. The THF was
evaporated and then extracted twice with CH2Cl2 and
the combined organic layers were washed with brine
and dried over MgSO4. The residue was purified by
flash chromatography to give by order of elution the
two diastereomeric alcohols 4 (sometimes contaminated
by minor amounts ca. 5% of 5) then 3.
3. Conclusion
We have devised an efficient two-steps procedure for
the preparation of the previously unknown enantiopure
alkylidene 1,1-bis-p-tolyl-sulfoxides (5). This study al-
lowed us to reexamine the diastereoselectivity of the
condensation reaction of 1 on aldehydes, and notably
to improve the results. The produced alcohols 3 and 4
are interesting precursors of enantiopure a-hydroxy
acids. No doubt also that alkylidene substrates will find
important applications in asymmetric synthesis.
4.1.1. (SS,SS,2S)-1,1-Di-p-tolylsulfinyl-hexan-2-ol (3a)
Yield: 67%. White solid, m.p. 114 °C. [h]2D0+141.2°
(c 1.5, CHCl3). Anal. Calc. for C20H26O3S2: C, 63.46;
H, 6.92. Found: C, 63.23; H, 7.13%. IR (cm−1) wmax
:
1
3447, 2962, 1084, 1055. H-NMR (CDCl3, 200 MHz):
l=7.62 (d, J=8.2 Hz, 2H), 7.40 (d, J=8.2 Hz, 2H),
7.22 (d, J=8.2 Hz, 2H), 7.02 (d, J=8.2 Hz, 2H), 4.49
(dd, J=8.3; 5.3 Hz, 1H), 3.32 (s, 1H), 2.47 (s, 3H), 2.36
(s, 3H), 1.85–1.76 (m, 1H), 1.37–1.29 (m, 1H), 1.22–
1.03 (m, 4H), 0.77 (t, J=6.7 Hz, 3H). 13C-NMR
(CDCl3, 50 MHz): l=142.2, 141.7, 139.8, 138.3, 130.3
(4C), 124.5 (2C), 123.7 (2C), 91.8, 67.0, 34.6, 27.3, 22.1,
21.5, 21.3, 13.8.
4. Experimental
All reactions were run under an Ar or N2 atmosphere
in anhydrous solvents and dried flask. Thin layer chro-
matography (TLC) was performed on Merck Silica Gel
60 F 254 and revealed with either an ultraviolet lamp

B. Delou6rie´ et al. / Journal of Organometallic Chemistry 643–644 (2002) 130–135
133
4.1.2. (SS,SS,2R)-1,1-Di-p-tolylsulfinyl-hexan-2-ol (4a)
4.1.6. (SS,SS,2S)-1,1-Di-p-tolylsulfinyl-2-phenyl-
Contaminated with ca. 5% of 5a. Yield: 15%. Color-
ethan-2-ol (3d)
1
less oil. IR (cm−1) wmax: 3447, 2962, 1084, 1055. H-
Yield: 67%. White solid, m.p. 151 °C. [h]2D0−56.5 (c
1.0, CHCl3). Anal. Calc. for C22H22O3S2: C, 63.43; H,
5.81. Found: C, 63.76; H, 5.59%. IR (cm−1) wmax: 3452,
NMR (CDCl3, 200 MHz): l=7.50 (d, J=8.2 Hz, 2H),
7.36 (d, J=8.2 Hz, 2H), 7.08 (d, J=8.2 Hz, 2H), 6.71
(d, J=8.2 Hz, 2H), 4.58 (m, 1H), 3.62 (d, J=8.6 Hz,
1H), 2.46 (s, 3H), 2.30 (s, 3H), 1.80–1.20 (m, 6H), 0.88
(t, J=7.0 Hz, 3H). 13C-NMR (CDCl3, 50 MHz): l=
142.4, 141.5, 141.0, 136.6, 130.2 (2C), 129.9 (2C), 124.8
(2C), 124.0 (2C), 89.6, 69.8, 34.1, 27.1, 22.4, 21.4, 21.2,
13.9.
1
2928, 1084, 1053. H-NMR (CDCl3, 200 MHz): l=
7.32–7.10 (m, 13H), 5.71 (bs, 1H), 3.54 (d, J=1.0 Hz,
1H), 2.41 (s, 3H), 2.39 (s, 3H). 13C-NMR (CDCl3, 50
MHz): l=141.9, 141.8, 139.8, 139.4, 137.8, 130.4 (2C),
130.1 (2C), 128.6 (2C), 127.9, 125.7 (2C), 123.9 (2C),
123.8 (2C), 93.9, 68.4, 21.4 (2C).
4.1.7. (SS,SS,2S)-1,1-Di-p-tolylsulfinyl-4,4-dimethyl-7-
trimethylsilyl-hept-6-yn-2-ol (3f)
4.1.3. (SS,SS,2S)-1,1-Di-p-tolylsulfinyl-3-methyl-
butan-2-ol (3b)
Yield: 62%. White solid, m.p. 109 °C. [h]2D0+69.7 (c
1.2, CHCl3). Anal. Calc. for C26H36O3S2Si: C, 63.89; H,
7.42. Found: C, 63.70; H, 7.62%. IR (cm−1) wmax: 3446,
2960, 2928, 2246, 2171, 1249, 1083, 1048. 1H-NMR
(CDCl3, 200 MHz): l=8.37 (d, J=8.4 Hz, 2H), 7.38
(d, J=8.4 Hz, 2H), 7.22 (d, J=8.4 Hz, 2H), 7.03 (d,
J=8.4 Hz, 2H), 4.70 (bd, J=7.4 Hz, 1H), 3.29 (d,
J=1.0 Hz, 1H), 2.46 (s, 3H), 2.34 (s, 3H), 2.02 (s, 2H),
1.90 (dd, J=14.3; 8.4 Hz, 1H), 1.29 (dd, J=14.3; 3.5
Hz, 1H), 0.93 (s, 3H), 0.84 (s, 3H), 0.07 (s, 9H).
13C-NMR (CDCl3, 50 MHz): l=142.2, 141.8, 139.6,
138.3, 130.3 (4C), 124.5 (2C), 123.7 (2C), 105.0, 93.2,
86.6, 64.7, 45.8, 33.7, 33.2, 27.1, 26.8, 21.5, 21.3, 0.1
(3C).
Yield: 66%. White solid, m.p. 116 °C. [h]2D0+158.0°
(c 1.2, CHCl3). Anal. Calc. for C19H24O3S2: C, 62.60;
H, 6.64. Found: C, 62.20; H, 6.83%. IR (cm−1) wmax
:
1
3420, 2961, 1084, 1050. H-NMR (CDCl3, 200 MHz):
l=7.65 (d, J=8.4 Hz, 2H), 7.41 (d, J=7.9 Hz, 2H),
7.21 (d, J=7.9 Hz, 2H), 6.97 (d, J=8.4 Hz, 2H), 4.07
(dd, J=8.9; 1.0 Hz, 1H), 3.48 (d, J=1.0 Hz, 1H), 2.47
(s, 3H), 2.34 (s, 3H), 1.92 (m, 1H), 0.91 (d, J=6.4 Hz,
3H), 0.50 (d, J=6.4 Hz, 3H). 13C-NMR (CDCl3, 50
MHz): l=142.2, 141.5, 139.7, 138.1, 130.3 (2C), 130.2
(2C), 124.5 (2C), 123.5 (2C), 90.3, 71.5, 31.7, 21.5, 21.3,
18.5, 18.4.
4.1.4. (SS,SS,2R)-1,1-Di-p-tolylsulfinyl-3-methyl-
butan-2-ol (4b)
4.1.8. (SS,SS,2R)-1,1-Di-p-tolylsulfinyl-4,4-dimethyl-7-
trimethylsilyl-hept-6-yn-2-ol (4f)
Contaminated with ca. 5% of 5b. Yield: 16%. Color-
less oil. IR (cm−1) wmax: 3420, 2961, 1084, 1051. H-
1
Contaminated with ca. 5% of 5f. Yield: 15%. Pale
NMR (CDCl3, 200 MHz): l=7.47 (d, J=8.1 Hz, 2H),
7.33 (d, J=8.1 Hz, 2H), 7.05 (d, J=8.1 Hz, 2H), 6.71
(d, J=8.1 Hz, 2H), 4.38 (ddd, J=10.2; 8.7; 5.1 Hz,
1H), 3.71 (d, J=8.7 Hz, 1H), 2.43 (s, 3H), 2.27 (s, 3H),
1.15 (dd, J=10.2; 6.6 Hz, 1H), 0.98 (d, J=6.6 Hz,
3H), 0.90 (d, J=6.6 Hz, 3H). 13C-NMR (CDCl3, 50
MHz): l=142.4, 141.4, 141.0, 136.5, 130.1 (2C), 129.8
(2C), 124.7 (2C), 124.0 (2C), 87.7, 73.0, 30.0, 21.3, 21.1,
19.6, 15.3.
yellow oil. IR (cm−1) wmax: 3446, 2961, 2927, 2245,
1
2171, 1249, 1084, 1045. H-NMR (CDCl3, 200 MHz):
l=7.52 (d, J=8.0 Hz, 2H), 7.39 (d, J=8.0 Hz, 2H),
7.10 (d, J=8.0 Hz, 2H), 6.73 (d, J=8.0 Hz, 2H), 4.77
(bt, J=8.9 Hz, 1H), 3.56 (d, J=8.9 Hz, 1H), 2.47 (s,
3H), 2.32 (s, 3H), 2.23 (s, 2H), 2.10 (dd, J=14.3; 1.0
Hz, 1H), 1.73 (dd, J=14.3; 9.6 Hz, 1H), 1.09 (s, 6H),
0.13 (s, 9H). 13C-NMR (CDCl3, 50 MHz): l=142.4,
141.5, 140.9, 137.0, 130.2 (2C), 130.0 (2C), 124.8 (2C),
124.0 (2C), 105.3, 90.6 (2C), 68.1, 45.1, 33.9 (2C), 27.2,
27.0, 21.5, 21.3, 0.1 (3C).
4.1.5. (SS,SS,2S)-3,3-Dimethyl-1,1-di-p-tolylsulfinyl-
butan-2-ol (3c)
Yield: 89%. White solid, m.p. 121–122 °C. [h]2D0+
89.5 (c 1.1, CHCl3). Anal. Calc. for C20H26O3S2: C,
4.1.9. (SS,SS)-1,1-Di-p-tolylsulfinyl-buta-1,3-diene (5e)
Yield: 56%. Pale yellow solid, m.p. 93–95 °C.
[h]2D5+162.0° (c 1.1, CHCl3). Anal. Calc. for
C18H18O2S2: C, 65.42; H, 5.49. Found: C, 65.32; H,
5.57%. IR (cm−1) wmax: 3050, 2920, 1595, 1490, 1080,
63.46; H, 6.92. Found: C, 63.18; H, 7.28%. IR (cm−1
)
wmax: 3430, 2961, 1085, 1051. 1H-NMR (CDCl3, 200
MHz): l=7.90 (d, J=8.4 Hz, 2H), 7.43 (d, J=7.9 Hz,
2H), 7.18 (d, J=7.9 Hz, 2H), 6.85 (d, J=8.4 Hz, 2H),
4.11 (d, J=3.7 Hz, 1H), 3.03 (d, J=3.7 Hz, 1H), 2.48
(s, 3H), 2.32 (s, 3H), 0.77 (s, 9H). 13C-NMR (CDCl3, 50
MHz): l=142.0, 141.3, 139.9, 138.6, 130.3 (2C), 130.2
(2C), 124.6 (2C), 123.4 (2C), 90.1, 71.5, 34.9, 26.3, 21.5,
21.3 (3C).
1
1045. H-NMR (CDCl3, 400 MHz): l=7.47 (d, J=
11.2 Hz, 1H), 7.23–7.16 (m, 3H), 7.02–6.93 (m, 6H),
5.85 (d, J=16.1 Hz, 1H), 5.77 (d, J=9.4 Hz, 1H), 2.31
(s, 3H), 2.28 (s, 3H). 13C-NMR (CDCl3, 50 MHz):
l=148.3, 142.6, 140.9, 139.1, 138.2, 137.9, 129.5 (4C),
126.5 (2C), 123.9 (2C), 129.1, 129.0, 21.5, 21.3.

134
B. Delou6rie´ et al. / Journal of Organometallic Chemistry 643–644 (2002) 130–135
4.2. General procedure for the dehydration of
bis-sulfinyl alcohols 3 and 4
69.44; H, 5.30. Found: C, 69.38; H, 5.36%. IR (cm−1
)
1
wmax: 3040, 2920, 1590, 1080, 1040. H-NMR (CDCl3,
400 MHz): l=7.94 (s, 1H), 7.64 (m, 2H), 7.42 (m, 3H),
7.21 (d, J=8.1 Hz, 2H), 6.93–6.86 (m, 6H), 2.25 (s,
3H), 2.23 (s, 3H). 13C-NMR (CDCl3, 100 MHz): l=
148.1, 142.3, 140.7, 139.7, 138.5, 137.4, 132.3, 130.9
(2C), 130.6 (2C), 129.5 (2C), 129.4 129.1 (2C), 126.3
(2C), 124.2 (2C), 21.4, 21.2.
To a solution of the mixture of alcohols 3 and 4 (2.0
mmol, one equivalent) in CH3CN (20 ml) were added
1.5–2.0 equivalents of 1-cyclohexyl-3-(2-morpholi-
noethyl)-carbodiimide metho-p-toluenesulfonate (8)
and a catalytic amount of CuCl2 (0.1 equivalent). The
reaction was controlled by TLC and was generally over
after 2–3 h at 70 °C. After cooling, the reaction mix-
ture was diluted in CH2Cl2 and filtered over a short pad
of celite and silica and concentrated in vacuo.
4.2.5. (SS,SS)-1,1-Di-p-tolylsulfinyl-4,4-dimethyl-7-
trimethylsilyl-hept-6-yn-2-ene (5f)
Yield: 65%. White solid, m.p. 134–135 °C. [h]D25
−
17.2° (c 1.1, CHCl3). Anal. Calc. for C26H34O2S2Si: C,
4.2.1. (SS,SS)-1,1-Di-p-tolylsulfinyl-hex-1-ene (5a)
66.33; H, 7.28. Found: C, 63.45; H, 7.35%. IR (cm−1
)
Yield: quant. White solid, m.p. 63–65 °C. [h]D25
−
wmax: 3054, 2961, 2253, 2170, 1249, 1084, 1045. 1H-
NMR (CDCl3, 200 MHz): l=7.21–7.15 (m, 3H),
7.00–6.92 (m, 6H), 2.84 (dd, J=14.8; 9.4 Hz, 1H), 2.64
(dd, J=14.8; 6.5 Hz, 1H), 2.31 (s, 3H), 2.29 (s, 3H),
2.23 (s, 2H), 1.12 (s, 6H), 0.14 (s, 9H). 13C-NMR
(CDCl3, 50 MHz): l=150.2, 142.3, 140.9, 140.1, 139.6,
137.6, 129.4 (4C), 126.3 (2C), 124.1 (2C), 104.0, 87.7,
40.1, 35.1, 33.3, 26.7, 26.6, 21.4, 21.3, 0.1 (3C).
3.0° (c 1.5, CHCl3). Anal. Calc. for C20H24O2S2: C,
66.63; H, 6.71. Found: C, 66.59; H, 6.82%. IR (cm−1
)
wmax: 3050, 2960, 2920, 1590, 1490, 1050. 1H-NMR
(CDCl3, 400 MHz): l=7.05 (dd, J=9.0; 6.7 Hz, 1H),
7.12 (d, J=8.1 Hz, 2H), 6.92–6.88 (m, 6H), 2.76–2.70
(m, 1H), 2.56–2.51 (m, 1H), 2.24 (s, 3H), 2.23 (s, 3H),
1.56–1.49 (m, 2H), 1.40–1.34 (m, 2H), 0.89 (t, J=7.3
Hz, 3H). 13C-NMR (CDCl3, 100 MHz): l=147.9,
143.3, 142.1, 140.7, 139.3, 137.5, 129.3 (4C), 126.1 (2C),
123.8 (2C), 30.6, 29.1, 22.1, 21.3, 21.1, 13.7.
4.3. Synthesis of the alcohol (+)-7
To a solution of alcohol 3b (500 mg, 1.37 mmol, one
equivalent) in dry CH2Cl2 (15 ml) at 0 °C, under a N2
atmosphere, were successively added 0.97 ml (6.90
mmol, five equivalents) of freshly distilled TFAA and
0.89 ml (10.96 mmol, eight equivalents) of dry pyridine
and stirred for 30 min. The reaction mixture was
quenched with cold water and diluted with CH2Cl2 (15
ml). The layers were separated and the organic layer
was washed with brine (15 ml), dried over MgSO4 and
evaporated to give 307 mg of an oil.
This oil was immediately dissolved in ether (10 ml)
and reduced with 70 mg (1.80 mmol) of LiAlH4. The
reaction mixture was stirred for 1 h at r.t., diluted with
CH2Cl2 (5 ml) and carefully hydrolyzed by an aq.
saturated Na2SO4 solution until precipitation of the
white aluminium salts. The precipitate was removed by
filtration over Celite and the crude product was purified
by silica gel chromatography.
4.2.2. (SS,SS)-1,1-Di-p-tolylsulfinyl-3-methyl-but-1-ene
(5b)
Yield: 90%. White solid, m.p. 105–107 °C. [h]2D5+
26.0 (c 1.3, CHCl3). Anal. Calc. for C19H22O2S2: C,
65.86; H, 6.40. Found: C, 65.82; H, 6.46%. IR (cm−1
)
1
wmax: 3040, 2970, 1595, 1085, 1045. H-NMR (CDCl3,
400 MHz): l=7.10 (d, J=8.1 Hz, 2H), 6.94–6.85 (m,
7H), 3.31–3.25 (m, 1H), 2.23 (s, 3H), 2.22 (s, 3H), 1.14
(d, J=6.5 Hz, 3H), 1.12 (d, J=6.5 Hz, 3H). 13C-NMR
(CDCl3, 100 MHz): l=149.6, 146.2, 142.6, 141.3,
140.0, 137.7, 129.8 (4C), 126.5 (2C), 124.4 (2C), 29.4,
22.5 (2C), 21.7, 21.6.
4.2.3. (SS,SS)-3,3-Dimethyl-1,1-di-p-tolylsulfinyl-
but-1-ene (5c)
Yield: 82%. White solid, m.p. 172–174 °C. [h]2D5−
123.0 (c 1.1, CHCl3). Anal. Calc. for C20H24O2S2: C,
66.63; H, 6.71. Found: C, 66.46; H, 6.81%. IR (cm−1
)
wmax: 3040, 2960, 1590, 1040. 1H-NMR (CDCl3, 400
MHz): l=7.12 (s, 1H), 6.96 (m, 4H), 6.86 (d, J=8.1
Hz, 2H), 6.80 (d, J=8.1 Hz, 2H), 2.21 (s, 3H), 2.17 (s,
3H), 1.33 (s, 9H). 13C-NMR (CDCl3, 100 MHz): l=
152.3, 145.5, 141.7, 140.7, 140.5, 138.5, 129.4 (2C),
129.2 (2C), 125.6 (2C), 124.6 (2C), 36.1, 31.1, 21.3, 21.2
(3C).
4.4. (+)-(S)-2-Methyl-3,4-butanediol (+)-7
Yield: 42%. Colorless oil. [h]2D0 +9.0° (c 3.0, CHCl3),
e.e. (GC) 92%. IR (cm−1) wmax: 3360, 2960, 2870. H-
1
NMR (CDCl3, 200 MHz): l=3.77–3.38 (m, 3H), 2.06
(bs, 2H), 1.70 (m, 1H), 0.97 (d, J=6.9 Hz, 3H), 0.91 (d,
J=6.9 Hz, 3H). 13C-NMR (CDCl3, 50 MHz): l=
77.1, 64.7, 30.8, 18.7, 18.2.
4.2.4. (SS,SS)-2-Phenyl-1,1-di-p-tolylsulfinyl-ethylene
(5d)
4.5. Synthesis of the alcohol (9)-7
Yield: 85%. White solid, m.p. 132–134 °C (dec.) [h]D25
−333.0° (c 1.2, CHCl3). Anal. Calc. for C22H20O2S2: C,
To a solution of 500 mg (4.24 mmol, one equivalent)

B. Delou6rie´ et al. / Journal of Organometallic Chemistry 643–644 (2002) 130–135
135
[4] Y. Arai, S. Kuwayama, Y. Takeuchi, T. Koizumi, Synth. Comm.
16 (1986) 233.
[5] G. Solladie´, F. Colobert, P. Ruiz, C. Hamdouchi, M. Carmen
Carren˜o, J.L. Garcia Ruano, Tetrahedron Lett. 32 (1991) 3695.
[6] J.C. Carretero, J.L. Garcia Ruano, L.M. Martin Cabrejas, Te-
trahedron Asymmetry 8 (1997) 409.
[7] Llera has shown that with piperidine the condensation of 1 onto
carbonyl derivatives gives (E)-g-hydroxyvinylsulfoxides through
a SPAC-type reaction. See: V. Guerrero-de la Rosa, M. Or-
don˜ez, F. Alcudia, J.M. Llera, Tetrahedron Lett. 36 (1995) 4889.
[8] For the synthesis of (S, S)-1. See: N. Kunieda, J. Nokami, M.
Kinoshita, Bull. Chem. Soc. Jpn. 49 (1976) 256.
[9] Presumably, the alkoxide deprotonates the disulfoxide and this is
rapidly followed by a LiOH elimination.
[10] V.K. Aggarwal, R.J. Franklin, J. Maddock, G.R. Evans, A.
Thomas, M.F. Mahon, K.C. Molloy, M.J. Rice, J. Org. Chem.
60 (1995) 2174.
[11] V.K. Aggarwal, S. Schade, H. Adams, J. Org. Chem. 62 (1997)
1139.
[12] V.K. Aggarwal, A. Thomas, S. Schade, Tetrahedron 53 (1997)
16213.
[13] P. Koch, Y. Nakatani, B. Luu, G. Ourisson, Bull. Soc. Chim. Fr.
(1983) 185.
of the commercially available (9)-2-hydroxy-3-methyl-
butyric acid in ether (10 ml) was added 177 mg (4.66
mmol, 1.1 equivalents) of LiAlH4. The reaction mixture
was stirred for 1 h at r.t., diluted with CH2Cl2 (5 ml)
and carefully hydrolyzed by an (aq.) saturated Na2SO4
solution until precipitation of the white aluminium
salts. The precipitate was removed by filtration over
Celite and the crude product was purified by silica gel
chromatography yielding (9)-7 in 75%.
Acknowledgements
We thank the CNRS for a Poste Rouge to Dr F.N.
and the Ministe`re for a grant to B.D. We feel grateful
to Dr Franc¸oise Colobert (Strasbourg) for helpful dis-
cussions and to Maxime Vitale for running some of
these experiments.
[14] C. Mioskowski, G. Solladie´, Tetrahedron 36 (1980) 227.
[15] G. Bartoli, M.C. Bellucci, M. Petrini, E. Marcantoni, L. Sambri,
E. Torregiani, Org. Lett. 2 (2000) 1791.
References
[16] E.M. Burgess, H.R.J. Penton, E.A. Taylor, J. Org. Chem. 38
(1973) 26.
[17] J.S. O’Grodnick, R.C. Ebersole, T. Wittstruck, E. Caspi, J. Org.
Chem. 39 (1974) 2124.
[1] J.K. Whitesell, Chem. Rev. 89 (1989) 1581.
[2] V.K. Aggarwal, J.K. Barrell, J.M. Worrall, R. Alexander, J.
Org. Chem. 63 (1998) 7128.
[3] V.K. Aggarwal, Z. Gultekin, R.S. Grainger, H. Adams, P.L.
Spargo, J. Chem. Soc. Perkin Trans. 1 (1998) 2771.
[18] V.K. Aggarwal, M. Lightowler, S.D. Lindell, Synlett (1992) 730.