Preparation of allyl sulfoxides by palladium-catalyzed allylic alkylation of sulfenate anions

Article abstract of DOI:10.1021/jo061359u

Palladium-catalyzed allylic alkylation of sulfenate anions, generated from β-sulfinylesters by retro-Michael reaction, can take place under biphasic conditions. This new reaction provides a simple, mild, and efficient route to allyl sulfoxides in good yields.

Full text of DOI:10.1021/jo061359u

Preparation of Allyl Sulfoxides by Palladium-Catalyzed Allylic
Alkylation of Sulfenate Anions
Guillaume Maitro, Guillaume Prestat, David Madec,* and Giovanni Poli*
Laboratoire de Chimie organique (UMR CNRS 7611), Institut de Chimie Mole´culaire (FR 2769),
UniVersite´ Pierre et Marie Curie-Paris 6, Case 183, 4 Place Jussieu, F-75252, Paris Cedex 05, France
gioVanni.poli@upmc.fr; daVid.madec@upmc.fr
ReceiVed June 30, 2006
Palladium-catalyzed allylic alkylation of sulfenate anions, generated from â-sulfinylesters by retro-Michael
reaction, can take place under biphasic conditions. This new reaction provides a simple, mild, and efficient
route to allyl sulfoxides in good yields.
SCHEME 1. Palladium-Catalyzed Allylic Alkylation of
Sulfur Nucleophiles
Introduction
Palladium-catalyzed allylic alkylation represents a primary
synthetic tool to generate carbon-carbon and carbon-hetero-
atom bonds.1 In particular, the use of sulfur-based nucleophiles2
such as sulfinates3 and thiolates4 allows the easy generation of
allyl sulfones and allyl ethers (Scheme 1). On the other hand,
no related methods allowing the generation of allyl sulfoxides
via allylation of a sulfenate anion has, to our knowledge, so far
been reported, probably because of the nonstraightforward
preparation of this nucleophile.5 Such a transformation is
expected to be of interest in light of the stereogenic nature of
the newly generated sulfoxide sulfur atom, as well as of the
(1) For reviews, see: (a) Tsuji, J. In Handbook of Organopalladium
Chemistry for Organic Synthesis; Negishi, E.-I., Ed.; John Wiley & Sons:
New York, 2002; Vol.1, pp 1669-1844. (b) Trost, B. M.; Vranken, D. L.
V. Chem. ReV. 1996, 96, 395-422. (c) Hegedus, L. S. Transition Metals
in the Synthesis of Complex Organic Molecules; University Science Book;
Mill Valley, 1994.
sulfoxide-sulfenate rearrangement,6 potentially associated to
the resulting products.
Results and Discussion
(2) Kondo, T.; Mitsudo, T.-A. Chem. ReV. 2000, 100, 3205-3220.
(3) For palladium-catalyzed allylic alkylation of sulfinates, see: Inomata,
K.; Yamamoto, T.; Kotake, H. Chem. Lett. 1981, 1357-1360.
(4) For palladium-catalyzed allylic alkylation of thiolates, see: Goux,
C.; Lhoste, P.; Sinou, D. Tetrahedron Lett. 1992, 33, 8099-8102. (b) Geneˆt,
J. P.; Blart, E.; Savignac, M.; Lemeune, S.; Lemaire-Audoire, S.; Bernard,
J. M. Synlett 1993, 680-682. (c) Goux, C.; Lhoste, P.; Sinou, D.
Tetrahedron 1994, 50, 10321-10330. (d) Kang, S.-K.; Park, D.-C.; Jeon,
J.-H.; Rho, H.-S.; Yu, C.-M. Tetrahedron Lett. 1994, 35, 2357-2360.
(5) (a) Hogg, D. R. Chemistry of Sulfenic Acids and Esters. The Chemistry
of Sulfenic Acids and their DeriVatiVes; Wiley-Interscience: Toronto, 1990;
pp 361-402. (b) Drabowicz, J.; Kielbasinski, P.; Mikolajczyk, M. The
Chemistry of Sulfenic Acids, Esters and their DeriVatiVes; Patai, S. Ed.;
John Wiley & Sons: New York, 1990; pp 351-429. (c) O’Donnell, J. S.;
Schwan, A. L. Sulfur Lett. 2004, 25, 183-211.
We recently described the Pd-catalyzed allylation of EWG-
stabilized R-sulfinyl carbanions,7 a delicate transformation that
could be successfully achieved by the use of specifically
developed biphasic conditions.8 In the course of this study we
(6) (a) Bikart, P.; Carson, F. W.; Jacobus, J.; Miller, E. G.; Mislow, K.
J. Am. Chem. Soc. 1968, 90, 4869-4876. (b) Evans, D. A.; Andrews, G.
C. Acc. Chem. Res. 1974, 7, 147-155.
(7) Maitro, G.; Prestat, G.; Madec, D.; Poli, G. Synlett 2006, 1055-
1058.
(8) Madec, D.; Prestat, G.; Martini, E.; Fristrup, P.; Poli, G.; Norrby,
P.-O. Org. Lett. 2005, 7, 995-998.
10.1021/jo061359u CCC: $33.50 © 2006 American Chemical Society
Published on Web 08/17/2006
J. Org. Chem. 2006, 71, 7449-7454
7449

Maitro et al.
SCHEME 2
SCHEME 4. Preparation of â-Sulfinylesters
SCHEME 3
TABLE 1. Optimization of Reaction Conditionsa
phase transfer
KOH
(equiv)
yield
(%)b
entry
catalytic system.
agent
1
2
3
4
5
[Pd(C3H5)Cl]2/dppe
[Pd(C3H5)Cl]2/dppe
[Pd(C3H5)Cl]2/dppe
[Pd(C3H5)Cl]2/dppe
n-Bu4NBr
n-Bu4NBr
n-Bu4NBr
2
10
20
20
20
50
70
88
86
0
a Reagents and reaction conditions: allyl acetate (2 equiv), â-sulfinylester,
n-Bu4NBr (10 mol % if used), [Pd(C3H5)Cl]2 (2 mol %), dppe (5 mol %),
KOH (50% aqueous solution, 2-20 equiv) in 1:1 CH2Cl2/H2O mixture.
b Yields are given for isolated products.
serendipitously observed that, under prolonged reaction time
and in the presence of an excess amount of the allylating agent,
reaction of acetylmethyl phenyl sulfoxide with allyl acetate gave
rise to allyl phenyl sulfoxide, instead of the expected allylated
ketone (Scheme 2).
We interpreted such a result on the basis of a sulfenic acid
elimination9 of the allylated sulfoxide, followed by addition of
potassium sulfenate to the transiently generated η3-allyl pal-
ladium complex (Scheme 3).
The latter step of the above sequence would represent an
unprecedented Pd-catalyzed allylation of sulfenate anions. With
the aim of confirming the envisaged mechanism and, if positive,
of studying the scope of the new transformation, we thus focused
our attention on this transformation.
To turn this observation into a general reaction, we decided
to distinguish the generation of the sulfenate anion from the
allylation step. Sulfenate anions are rather unstable species and
are usually generated in situ. Among the several options reported
in the literature10 our choice went to the base-promoted
elimination of â-sulfinylesters, recently described by Perrio and
Metzner.11 Accordingly, the three sulfenate precursors 2a-c
have been prepared by addition of p-thiocresol, 2-thionaphthol,
or 2-propanethiol to tert-butyl acrylate followed by Oxone-
promoted thioether-to-sulfoxide oxidation of the resulting thio-
ethers 1a-c in the presence of wet alumina (Scheme 4).12
The Pd-catalyzed allylation between the in situ generated
p-tolyl sulfenate anion and allyl acetate was chosen as the model
reaction (Table 1). Much to our satisfaction, treatment of the
two substrates with [Pd(C3H5)Cl]2 (2 mol %), dppe (5 mol %),
nBu4NBr (10 mol %), and KOH (2.0 equiv) in 1:1 CH2Cl2/
H2O gave, after 16 h at room temperature, the expected allyl
p-tolyl sulfoxide in 50% yield (entry 1). An increase of the
amount of KOH to 10 and 20 equiv, under otherwise identical
conditions, raised the yield to 70% and 88%, respectively
(entries 2 and 3). Interestingly, the presence of the phase transfer
agent turned out to be unnecessary for the reaction (entry 4).
Finally, an experiment performed in the absence of the palladium
catalyst gave only partial degradation of the starting sulfinylester,
thereby confirming the compulsory involvement of a η3-
allylpalladium intermediate (entry 5).
With the optimized reaction conditions in hand, scope and
limitations of the transformation were then evaluated (Table 2).
Reaction between the p-tolyl sulfenate precursor 2a and
cinnamyl acetate gave the corresponding cinnamyl sulfoxide
4a in 82% yield (entry 2). The same product was also obtained,
(10) (a) Katritzky, A. R.; Takahashi, I.; Marson, C. M. J. Org. Chem.
1986, 51, 4914-4920. (b) O’Donnell, J. S.; Schwan, A. L. Tetrahedron
Lett. 2003, 44, 6293-6296. (c) Maezaki, N.; Yoshigami, R.; Maeda, J.;
Tanaka, T. Org. Lett. 2001, 3, 3627-3629. (d) Maezaki, N.; Yagi, S.;
Ohsawa, S.; Ohishi, H.; Tanaka, T. Tetrahedron 2003, 59, 9895-9906. (e)
Maezaki, N.; Yagi, S.; Yoshigami, R.; Maeda, J.; Suzuki, T.; Ohsawa, S.;
Tsukamoto, K.; Tanaka, T. J. Org. Chem. 2003, 68, 5550-5558. (f)
Maezaki, N.; Yagi, S.; Maeda, J.; Yoshigami, R.; Tanaka, T. Heterocycles
2004, 62, 263-277. (g) Sandrinelli, F.; Perrio, S.; Beslin, P. J. Org. Chem.
1997, 62, 8626-8627. (h) Sandrinelli, F.; Perrio, S.; Beslin, P. Org. Lett.
1999, 1, 1177-1180. (i) Sandrinelli, F.; Perrio, S.; Averbuch-Pouchot, M.-
T. Org. Lett. 2002, 4, 3619-3622. (j) Sandrinelli, F.; Fontaine, G.; Perrio,
S.; Beslin, P. J. Org. Chem. 2004, 69, 6916-6919. (k) Aversa, M. C.;
Bonaccorsi, P.; Faggi, C.; Lamanna, G.; Menichetti, S. Tetrahedron 2005,
61, 11902-11909. (l) Martin, C.; Sandrinelli, F.; Perrio, C.; Perrio, S.;
Lasne, M.-C. J. Org. Chem. 2006, 71, 210-214.
(9) (a) Trost, B.; Weber, L.; Strege, P.; Fullerton, T.; Dietsche, T. J.
Am. Chem. Soc. 1978, 100, 3426-3435. (b) Trost, B. M.; Salzmann, T.
N.; Hiroi, K. J. Am. Chem. Soc. 1976, 98, 4887-4902.
(11) Caupe`ne, C.; Boudou, C.; Perrio, S.; Metzner, P. J. Org. Chem.
2005, 70, 2812-2815.
(12) Greenhalgh, R. P. Synlett 1992, 235-236.
7450 J. Org. Chem., Vol. 71, No. 19, 2006

Preparation of Allyl Sulfoxides
TABLE 2. Scope of the Reactiona
a Reagents and reaction conditions: allyl acetate (2 equiv), â-sulfinylesters, [Pd(C3H5)Cl]2 (2 mol %), dppe (5 mol %), KOH (50% aqueous solution, 20
equiv) in 1:1 CH2Cl2/H2O mixture. b Yields are given for isolated products. c Diastereomeric ratios determined by 1H NMR. d Use of cyclohex-2-enyl acetate
in place of cyclopent-2-enyl acetate did not allow generation of the corresponding sulfoxide.
albeit in a slightly lower yield, starting from the corresponding
branched isomer (entry 3). Cyclic allylic acetates were then
tested. In the event, cyclopent-2-enyl acetate gave cyclopent-
2-enyl p-tolyl sulfoxide 5a in 65% yield as an equimolar
diastereomeric mixture (entry 4). More disappointingly,
cyclohex-2-enyl acetate afforded the corresponding sulfoxide
6a in a limited 14% yield as a 86:14 (R*,S*/R*,R*) ratio (entry
5).13,14
Reaction between the 2-naphthyl sulfenate precursor 2b and
allyl or cinnamyl acetate afforded the corresponding 2-naphthyl
sulfoxides 3b and 4b in 63% yield (entries 6 and 7). Cyclic
allylic acetates gave variable results. Indeed, whereas cyclopent-
2-enyl acetate gave the corresponding sulfoxide 5b in 54% yield
(entry 8), cyclohex-2-enyl acetate did not allow generation of
the expected homologous product. Alkyl sulfenates could also
be satisfactorily entered. Thus, starting from 3-isopropylsulfinyl
tert-butyl ester 2c (R1 ) i-Pr), reaction with allyl or cinnamyl
acetate afforded the corresponding isopropyl sulfoxides 3c or
4c in 83% and 59% yield, respectively (entries 9 and 10).
Interestingly, with this alkyl sulfenate both the cyclic acetates
cyclopent-2-enyl acetate and cyclohex-2-enyl acetate gave the
expected corresponding sulfoxides 5c and 6c in 43% and 57%
yield (entries 11 and 12).
We propose for this new allylation reaction the following
mechanism (Scheme 5). KOH-mediated deprotonation of the
â-sulfinylester, which likely takes place in the interfacial zone,15
first gives the corresponding potassium ester enolate.11 The
following retro-Michael reaction generates a lypophilic acrylate
ester and a sulfenate anion. Finally, interaction of the latter
(13) (a) Alajar´ın, M.; Pastor, A.; Cabrera, J. Synlett 2004, 995-998. (b)
Knight, D. J.; Lin, P.; Russell, S. T.; Whitham, G. H. J. Chem. Soc., Perkin
Trans. 1 1987, 2701-2705.
(14) The major diastereoisomer of this reaction corresponds to the minor
one obtained from sulfoxide-sulfenate rearrangement, ref 13.
J. Org. Chem, Vol. 71, No. 19, 2006 7451

Maitro et al.
SCHEME 5
1H NMR (CDCl3, 400 MHz): δ 7.83-7.78 (m, 4H), 7.53-7.45
(m, 3H), 3.27 (t, J ) 7.3 Hz, 2H), 2.63 (t, J ) 7.3 Hz, 2H), 1.50
(s, 9H). 13C NMR (CDCl3, 100 MHz): δ 171.1, 133.8, 133.1, 132.0,
128.6, 127.9, 127.8, 127.2, 126.6, 125.9, 81.0, 35.5, 29.0, 28.1. IR
(powder): 2989, 1737, 1362, 1223, 1168, 822, 750 cm-1. MS (CI/
NH3): m/z 306 (MNH4+), 289 (MH+), 250, 233. Anal. Calcd for
C17H20O2S: C, 70.80; H, 6.99; S, 11.12. Found: C, 70.73; H, 6.91;
S, 10.89. Mp 62-64 °C.
species with a transiently generated η3-allyl palladium complex,
in turn derived from the allylic derivative, gives the allyl
sulfoxide and regenerates the Pd(0) catalyst.
Conclusion
We have reported the first palladium-catalyzed allylation of
sulfenate anions. This new, smooth, and operationally very
simple method further extends the set of sulfur-based nucleo-
philes that can be successfully allylated under palladium
catalysis. The stereogenic nature of the sulfur atom in the
generated allyl sulfoxides, and the potential sulfoxide-sulfenate
rearrangement associated to these compounds are expected to
make of this reaction a synthetically interesting transformation.
Further Pd-catalyzed C-S bond formations involving sulfenate
anions as nucleophilic partners are presently under investigation
and will be reported in due course.
3-Isopropylsulfanyl-propionic Acid tert-Butyl Ester (1c). The
reaction was performed with a stoechiometric amount of K2CO3
for 36 h to give a colorless oil (94% yield), which was used without
1
further purification. H NMR (CDCl3, 400 MHz): δ 2.93 (h, J )
6.6 Hz, 1H), 2.74 (t, J ) 7.6 Hz, 2H), 2.49 (t, J ) 7.6 Hz, 2H),
1.45 (s, 9H), 2.51 (d, J ) 6.6 Hz, 6H). 13C NMR (CDCl3, 100
MHz): δ 171.4, 80.7, 36.2, 34.9, 28.1, 25.6, 23.4. IR (neat): 2950,
1729, 1456, 1366, 1249, 1142, 845 cm-1. MS (CI/NH3): m/z 222
(MNH4+), 205 (MH+), 149. HRMS calcd for C10H20O2S (M+)
204.1184, found 204.1177.
Experimental Procedure and Characterization Data for
â-Sulfinyl Esters. A dry dichloromethane solution (25 mL) of
thioether (10 mmol) was added to a suspension of wet neutral
alumine oxide (10 g, ratio alumina oxide/water ) 5 g for 1 mL)
and Oxone in dry dichloromethane (25 mL) at room temperature.
The reaction mixture was refluxed for 3 h, then cooled to room
temperature, filtered, and evaporated under reduced pressure. The
crude residue was then purified by flash chromatography.
3-(p-Toluenesulfinyl)-propionic Acid tert-Butyl Ester (2a).
Purification by silica gel flash chromatography (ethyl acetate/
cyclohexane, 3:2 f 7:3) followed by recrystallization from n-
Experimental Section
Experimental Procedure and Characterization Data for
â-Sulfanyl Esters. To a solution of thiol (20 mmol) and potassium
carbonate (5 mol %) in dichloromethane (5 mL) was added rapidly
tert-butyl acrylate (3.2 mL, 22 mmol). After 20 h of stirring, water
was added to the mixture and the organic layer was successively
washed with water (twice) and brine, then dried over anhydrous
MgSO4, and evaporated under reduced pressure. The resulting crude
product was purified by flash chromatography.
3-p-Tolylsulfanyl-propionic Acid tert-Butyl Ester (1a). Puri-
fication by silica gel flash chromatography (cyclohexane/ethyl
acetate, 95:5) afforded the product as a colorless oil (89% yield).
1H NMR (CDCl3, 400 MHz): δ 7.31 (d, J ) 8.1 Hz, 2H), 7.13 (d,
J ) 8.1 Hz, 2H), 3.10 (t, J ) 7.6 Hz, 2H), 2.53 (t, J ) 7.6 Hz,
2H), 2.34 (s, 3H), 1.47 (s, 9H). 13C NMR (CDCl3, 100 MHz): δ
171.2, 136.8, 131.7, 131.0, 129.9, 80.9, 35.7, 30.0, 28.2, 21.1. IR
(powder): 2977, 1726, 1492, 1392, 1248, 1144, 803 cm-1. MS
(CI/NH3): m/z 270 (MNH4+), 253 (MH+), 214, 197. HRMS calcd
for C14H20O2S (M+) 252.1184, found 252.1206.
1
hexane afforded the product as colorless crystals (87% yield). H
NMR (CDCl3, 400 MHz): δ 7.52 (d, J ) 8.1 Hz, 2H), 7.35 (d, J
) 8.1 Hz, 2H), 3.16 (ddd, J ) 15.4, 8.6, 6.6 Hz, 1H), 2.94 (ddd,
J ) 15.4, 8.6, 5.6 Hz, 1H), 2.75 (ddd, J ) 17.2, 8.6, 6.8 Hz, 1H),
2.46 (ddd, J ) 17.2, 8.6, 5.6 Hz, 1H), 2.45 (s, 3H), 1.44 (s, 9H).
13C NMR (CDCl3, 100 MHz): δ 170.5, 141.6, 139.9, 130.1, 124.1,
81.5, 51.6, 28.1, 27.4, 21.5. IR (powder): 2977, 1727, 1424, 1349,
1244, 1153, 1037, 812 cm-1. MS (CI/NH3): m/z 269 (MH+), 230,
213. Anal. Calcd for C14H20O3S: C, 62.66; H, 7.51; S, 11.95.
Found: C, 62.53; H, 7.73; S, 12.11. Mp 61-62 °C.
3-(Naphthalene-2-sulfinyl)-propionic Acid tert-Butyl Ester
(2b). Purification by silica gel flash chromatography (cyclohexane/
ethyl acetate, 3:2 f 1:1) gave the pure product as a white solid
(85% yield). 1H NMR (CDCl3, 400 MHz): δ 8.18 (d, J ) 1.5 Hz,
1H), 7.97-7.88 (m, 3H), 7.60-7.55 (m, 3H), 3.27 (ddd, J ) 15.2,
8.3, 6.7 Hz, 1H), 3.00 (ddd, J ) 15.2, 8.3, 5.8 Hz, 1H), 2.78 (ddd,
J ) 17.2, 8.3, 6.8 Hz, 1H), 2.45 (ddd, J ) 17.2, 8.6, 5.8 Hz, 1H),
1.38 (s, 9H). 13C NMR (CDCl3, 100 MHz): δ 170.4, 140.1, 134.5,
132.9, 129.5, 128.5, 128.1, 127.8, 127.4, 124.8, 119.8, 81.5, 51.0,
28.0, 27.2. IR (powder): 2970, 1721, 1351, 1247, 1147, 1074, 1043,
3-(Naphthalen-2-ylsulfanyl)-propionic Acid tert-Butyl Ester
(1b). Purification by silica gel flash chromatography (cyclohexane/
ethyl acetate, 95:5) followed by recrystallization from ethanol/
dichloromethane (95:5) mixture gave a white solid (84% yield).
(15) (a) Makosza, M.; Krylowaa, I. Tetrahedron 1999, 55, 6395-6402.
(b) Mason, D.; Magdassi, S.; Sasson, Y. J. Org. Chem. 1990, 55, 2714-
2717. (c) Gobbi, A.; Landini, D.; Maia, A.; Petricci, S. J. Org. Chem. 1998,
63, 5356-5361. (d) Lygo, B.; Andrews, B. Acc. Chem. Res. 2004, 37, 518-
525.
7452 J. Org. Chem., Vol. 71, No. 19, 2006

Preparation of Allyl Sulfoxides
820, 752 cm-1. MS (CI/NH3): m/z 610, 305 (MH+), 266, 249. Anal.
Calcd for C17H20O3S: C, 67.08; H, 6.62; S, 10.53. Found: C, 66.68;
H, 6.77; S, 10.53. Mp 93-95 °C.
125.0, 120.3 and 119.9, 63.1 and 61.6, 25.1 and 24.8, 23.4 and
21.7, 20.2 and 19.1. Spectral data were in agreement with those
previously reported.19
3-(Propane-2-sulfinyl)-propionic Acid tert-Butyl Ester (2c).
Purification by silica gel flash chromatography (cyclohexane/ethyl
acetate, 1:1 f 0:10) afforded the pure product as a colorless oil
(80% yield). 1H NMR (CDCl3, 400 MHz): δ 2.93-2.84 (m, 1H),
2.78-2.66 (m, 4H), 1.41 (s, 9H), 1.28 (d, J ) 6.8 Hz, 3H), 1.23
(d, J ) 6.8 Hz, 3H). 13C NMR (CDCl3, 100 MHz): δ 170.7, 81.5,
50.7, 43.7, 28.5, 28.0, 15.8, 14.8. IR (neat): 2975, 1726, 1366,
Allyl-2-naphthyl Sulfoxide (3b). Purification by silica gel flash
chromatography (cyclohexane/ethyl acetate, 95:5 f 7:3) afforded
1
the product as a pale yellow solid (63% yield). H NMR (CDCl3,
400 MHz): δ 8.17 (s, 1H), 8.0-7.91 (m, 3H), 7.62-7.58 (m, 3H),
5.72-5.62 (m, 1H), 5.35-5.32 (m, 1H), 5.23 (dd, J ) 16.9, 1.3
Hz, 1H), 3.68 (dd, J ) 12.9, 7.8 Hz, 1H), 3.59 (dd, J ) 12.9, 7.3
Hz, 1H). 13C NMR (CDCl3, 100 MHz): δ 140.1, 134.6, 132.8,
129.3, 128.6, 128.2, 127.9, 127.4, 125.3, 125.2, 124.1, 120.2, 60.6.
Spectral data were in agreement with those previously reported.20
Cinnamyl-2-naphthyl Sulfoxide (4b). Purification by silica gel
chromatography (cyclohexane/ethyl acetate, 94:6 f 8:2) afforded
1245, 1153, 1020, 842 cm-1. MS (CI/NH3): m/z 441, 238 (MNH4+),
+
221 (MH+), 165. HRMS calcd for C7H14O3S (M - C3H6
178.0664, found: 178.0650.
)
General Procedure for Palladium-Catalyzed Allylic Alkyl-
ation of Sulfenate Ions under Biphasic Conditions and Char-
acterization Data for Allylic Sulfoxides. To a solution of
allylpalladium chloride dimer (2 mol %) in dichloromethane (500
µL) was added dppe (5 mol %). The solution was stirred at room
temperature for 5 min. Then, a solution of the acetate substrate
(0.6 mmol in 1.5 mL of dichloromethane), â-sulfinylester (0.3 mmol
in 1.5 mL of dichloromethane), 3.5 mL of distilled water, and 50%
aqueous KOH solution (6 mmol) were successively added. The
resulting biphasic system was stirred vigorously at room temperature
for 1 h. Then, the aqueous phase was extracted twice with
dichloromethane, the collected organic layers were dried over
anhydrous MgSO4, and the solvent was removed under reduced
pressure. The crude product was purified by flash chromatography.
Allyl-p-tolyl Sulfoxide (3a). Purification by silica gel flash
chromatography (cyclohexane/ethyl acetate, 3:2) afforded the
1
the product as a pale yellow solid (63% yield). H NMR (CDCl3,
400 MHz): δ 8.18 (s, 1H), 7.99 (d, J ) 8.6 Hz, 1H), 7.93-7.91
(m, 2H), 7.64-7.57 (m, 3H), 7.31-7.23 (m, 5H), 6.48 (d, J )
15.7 Hz, 1H), 6.02 (ddd, J ) 15.7, 7.8, 7.6 Hz, 1H), 3.84-3.74
(m, 2H). 13C NMR (CDCl3, 100 MHz): δ 140.2, 138.6, 136.1,
134.6, 132.8, 129.3, 128.7, 128.6, 128.3, 128.1, 127.9, 127.4, 126.6,
125.2, 120.3, 116.2, 60.7. IR (powder): 3045, 1036, 966, 818, 742
cm-1. MS (CI/NH3): m/z 585, 310 (MNH4+), 293 (MH+), 117.
HRMS calcd for C10H7OS (M - C9H9+) 175.0218, found: 175.0206.
Mp 133-135 °C.
(Cyclopent-2-enyl)-2-naphthalene Sulfoxide (5b): Purification
by silica gel chromatography (cyclohexane/ethyl acetate, 9:1 f 8:2)
gave a mixture of two diastereoisomers (A and B) in a 70:30 ratio
1
and as a yellow oil (54% yield). H NMR (CDCl3, 400 MHz): δ
8.19-8.17 (m, 2H(A+B)), 7.99-7.91 (m, 6H(A+B)), 7.64-7.58 (m,
6H(A+B)), 6.19-6.15 (m, 2H(A+B)), 5.56-5.52 (m, 2H(A+B)), 4.10-
4.08 (m, 1H(A)), 4.02-3.99 (m, 1H(B)), 2.54-2.16 (m, 6H(A+B)),
2.05-1.97 (m, 2H(A)). 13C NMR (CDCl3, 100 MHz): δ 140.2 and
139.4, 140.1 and 139.6, 134.6 and 134.5, 132.9 and 132.8, 129.2
and 128.9, 128.7(A+B), 128.2(A+B), 127.8 and 127.7, 127.3(A+B), 125.5
and 125.4, 125.1 and 123.5, 120.8(A+B), 73.4 and 71.8, 32.6 and
32.1, 24.5 and 22.9. IR (neat): 2912, 1067, 1041, 814, 732, 654
cm-1. MS (CI/NH3): m/z 351, 260 (MNH4+), 243 (MH+), 225,
176. HRMS calcd for C20H14O2S2 (M - C5H8+)2 350.0435, found
350.0402.
1
product as a pale yellow oil (86% yield). H NMR (CDCl3, 400
MHz): δ 7.47 (d, J ) 8.1 Hz, 2H), 7.30 (d, J ) 7.8 Hz, 2H),
5.68-5.57 (m, 1H), 5.31 (d, J ) 10.1 Hz, 1H), 5.18 (dd, J ) 17.2,
1.3 Hz, 1H), 3.54 (dd, J ) 12.6, 7.3 Hz, 1H), 3.48 (dd, J ) 12.6,
7.6 Hz, 1H), 2.40 (s, 3H). 13C NMR (CDCl3, 100 MHz): δ 141.6,
139.7, 129.8, 125.4, 124.4, 123.8, 61.0, 21.5. Spectral data were in
agreement with those previously reported.16
Cinnamyl-p-tolyl Sulfoxide (4a). Purification by silica gel flash
chromatography (cyclohexane/ethyl acetate, 3:2) afforded a pale
yellow solid (82% yield). 1H NMR (CDCl3, 400 MHz): δ 7.51 (d,
J ) 8.3 Hz, 2H), 7.33-7.27 (m, 7H), 6.45 (d, J ) 15.9 Hz, 1H),
5.99 (dt, J ) 15.9, 7.6 Hz, 1H), 3.74-3.66 (m, 2H), 2.44 (s, 3H).
13C NMR (CDCl3, 100 MHz): δ 141.7, 139.8, 138.4, 136.3, 129.9,
128.7, 128.3, 126.6, 124.5, 116.4, 61.0, 21.6. Spectral data were in
agreement with those previously reported.17
Allyl-isopropyl Sulfoxide (3c). Purification by silica gel flash
chromatography (ethyl acetate/cyclohexane, 8:2) afforded a pale
yellow oil (83% yield). 1H NMR (CDCl3, 400 MHz): δ 5.89 (dddd,
J ) 17.7, 10.1, 7.6, 7.3 Hz, 1H), 5.39 (dd, J ) 10.1, 1.3 Hz, 1H),
5.35 (dd, J ) 17.7, 1.3 Hz, 1H), 3.42 (dd, J ) 13.1, 7.3 Hz, 1H),
3.33 (dd, J ) 13.1, 7.6 Hz, 1H), 2.81 (h, J ) 6.9 Hz, 1H), 1.29 (d,
J ) 6.9 Hz, 3H), 1.23 (d, J ) 6.9 Hz, 3H). 13C NMR (CDCl3, 100
MHz): δ 126.3, 123.0, 52.6, 48.7, 16.3, 14.3. IR (neat): 2966,
1462, 1017, 926 cm-1. MS (CI/NH3): m/z 150 (MNH4+), 133
(MH+). HRMS calcd for C6H12OS (M+) 132.0609, found 132.0596.
Cinnamyl-isopropyl Sulfoxide (4c). Purification by silica gel
flash chromatography (ethyl acetate/cyclohexane, 75:25) afforded
(Cyclopent-2-enyl)-p-tolyl Sulfoxide (5a). Purification by silica
gel flash chromatography (cyclohexane/ethyl acetate 3:2) gave the
product as a mixture of two diastereoisomers (A and B) in a 1:1
1
ratio and as a pale yellow oil (65% yield). H NMR (CDCl3, 400
MHz): δ 7.47-42 (m, 4H(A+B), 7.27-7.24 (m, 4H(A+B)), 6.10-
6.06 (m, 2H(A+B)), 5.52-5.49 (m, 1H(A)), 5.43-5.41 (m, 1H(B)),
3.93-3.89 (m, 1H(A)), 3.84-3.80 (m, 1H(B)), 2.37 (s, 6H(A+B)),
2.34-1.93 (m, 8H(A+B)). Spectral data were in agreement with those
previously reported.18
1
a pale yellow solid (59% yield). H NMR (CDCl3, 400 MHz): δ
7.42-7.41 (m, 2H), 7.39-7.28 (m, 2H), 7.27-7.25 (m, 1H), 6.68
(d, J ) 15.9 Hz, 1H), 6.29 (ddd, J ) 15.7, 7.8, 7.8 Hz, 1H), 3.62
(dd, J ) 13.1, 7.8 Hz, 1H), 3.53 (dd, J ) 13.1, 7.8 Hz, 1H), 2.88
(h, J ) 6.8 Hz, 1H), 1.35 (d, J ) 6.8 Hz, 3H), 1.29 (d, J ) 6.8 Hz,
3H). 13C NMR (CDCl3, 100 MHz): δ 137.4, 136.1, 128.7, 128.3,
126.6, 117.2, 52.5, 48.7, 16.4, 14.3. IR (neat): 2967, 1494, 1398,
1032, 972, 754, 697, 640 cm-1. MS (CI/NH3): m/z 417, 226
(MNH4+), 209 (MH+). HRMS calcd for C9H7 (M - C3H7OS+)
115.0548, found 115.0559. Mp 54-55 °C.
(Cyclohex-2-enyl)-p-tolyl Sulfoxide (6a). Purification by silica
gel flash chromatography (cyclohexane/ethyl acetate 3:2) afforded
the product as a mixture of two diastereoisomers in a 86:14 ratio
1
and as a yellow oil (14% yield). H NMR (CDCl3, 400 MHz): δ
7.61-7.51 (m, 4H(A+B)), 7.38-7.31 (m, 4H (A+B)), 6.15-6.12 (m,
1H(A)), 6.02-5.99 (m, 1H(B)), 5.69-5.67 (m, 1H(A)), 5.16-5.13 (m,
1H(B)), 3.36-3.28 (m, 2H(A+B)), 2.44 (s, 3H(A)), 2.42 (s, 3H(B)),
2.37-2.31 (m, 2H(A+B)), 2.10-2.04 (m, 4H(A+B)), 1.96-1.80 (m,
4H(A+B)), 1.74-1.68 (m, 2H(A+B)). 13C NMR (CDCl3, 100 MHz):
δ 141.8(A+B), 139.0(A+B), 135.2(A+B), 130.1 and 129.8, 125.5 and
(Cyclopent-2-enyl)-isopropyl Sulfoxide (5c). Purification by
silica gel flash chromatography (ethyl acetate/cyclohexane, 75:25
(16) Antonjuk, D. J.; Ridley, D. D.; Smal, M. A. Aust. J. Chem. 1980,
33, 2635-2651.
(19) D. J.; Lin, P.; Russel, S. T.; Whitham, G. H. J. Chem. Soc., Perkin
Trans. 1 1987, 12, 2701-2705. In our work, the major diastereomer is
(R*,S*).
(20) Yadav, J. S.; Subba Reddy, B. V.; Srinivas, C.; Srihari, P. Synlett
2001, 854-856.
(17) Goldmann, S.; Hoffmann, R. W.; Maak, N.; Geueke, K. J. Chem.
Ber. 1980, 113, 831-844.
(18) Snider, B. B. J. Org. Chem. 1981, 46, 3155-3157.
J. Org. Chem, Vol. 71, No. 19, 2006 7453

Maitro et al.
f 9:1) afforded a mixture of two diastereoisomers (A and B) in a
55:45 ratio and as a pale yellow oil (43% yield). 1H NMR (CDCl3,
400 MHz): δ 6.24-6.21 (m, 1H(A)), 6.15-6.13 (m, 1H(B)), 5.85-
5.82 (m, 1H(A)), 5.61 (m, 1H(B)), 3.92-3.89 (m, 1H(A)), 3.83-3.80
(m, 1H(B)), 2.84-2.71 (m, 2H(A+B)), 2.55-1.99 (m, 4H(A+B)), 1.32
(d, J ) 6.56 Hz, 6H(B)), 1.29 (d, J ) 6.95 Hz, 6H(A)). 13C NMR
(CDCl3, 100 MHz): δ 139.0 and 138.9, 124.9 and 124.2, 65.2 and
63.7, 48.2 and 47.8, 32.7 and 32.0, 25.0 and 22.8, 17.6 and 17.2,
1.36-1.27 (m, 6H(A+B)). 13C NMR (CDCl3, 100 MHz): δ 135.6
and 134.6, 120.1 and 119.7, 55.1 and 53.2, 47.0 and 45.2, 25.0
and 24.7, 24.0 and 21.4, 20.2 and 18.7, 18.4 and 17.5, 13.8 and
12.3. IR (neat): 2928, 1446, 1050, 1013, 726, 637 cm-1. MS (CI/
NH3): m/z 345, 190 (MNH4+), 173 (MH+). HRMS calcd for
C9H16OS (MH+) 172.0922, found: 172.0917.
Acknowledgment. The support and sponsorship by CNRS
and COST Action D24 "Sustainable Chemical Processes:
Stereoselective Transition Metal-Catalysed Reactions" are kindly
acknowledged.
14.7 and 14.0. IR (neat): 2929, 1728, 1459, 1156, 1011, 736 cm-1
.
MS (CI/NH3): m/z 317, 176 (MNH4+), 165, 159 (MH+).
(Cyclohex-2-enyl)-isopropyl Sulfoxide (6c). Purification by
silica gel flash chromatography (ethyl acetate/cyclohexane, 75:25
f 9:1) gave a mixture of two diastereoisomers (A and B) in a
55:45 ratio and as a pale yellow oil (57% yield). 1H NMR (CDCl3,
400 MHz): δ 6.17-6.13 (m, 1H(A)), 6.08-6.03 (m, 1H(B)), 5.83-
5.80 (m, 1H(A)), 5.49-5.45 (m, 1H(B)), 3.33-3.32 (m, 1H(A)), 3.24-
3.23 (m, 1H(B)), 2.92-2.78 (m, 1H(A+B)), 2.37-1.52 (m, 6H(A+B)),
Supporting Information Available: 1H and 13C NMR spectra
for all new compounds. This material is available free of charge
via the Internet at http://pubs.acs.org.
JO061359U
7454 J. Org. Chem., Vol. 71, No. 19, 2006