[2 + 1] Cycloaddition Reactions of a 1-Seleno-2-silylethene to 2-Sulfonylacrylates: Stereoselective Synthesis of Sulfone-Substituted Cyclopropanes

Article abstract of DOI:10.1021/jo9911591

Reaction of 1-(phenylseleno)-2-(trimethylsilyl)ethene 1 and methyl or ethyl 2-p-toluene- or benzene-sulfonylacrylates 3 in the presence of SnCl₄ at -78°C gave sulfone-substituted cyclopropanes 4 as single stereoisomers. The structure of one of these crystalline cyclopropane products was elucidated by X-ray crystallographic analysis. The relative stereochemistry of the cyclopropane ring carbon (C₂) and selenosilylmethyl group was determined as R,R and S,S, which is consistent with previous mechanical considerations and the NOE determination. 2-Sulfinyl acrylate 2 did not undergo this cycloaddition. The difference in reactivity of the sulfoxide 2 and sulfones 3 toward 1 was explained by comparison of LUMO levels of 2-SnCl₄ and 3-SnCl₄ complexes and activation energies in the synclinal addition of 1 to the complexes.

Full text of DOI:10.1021/jo9911591

J . Org. Chem. 1999, 64, 9521-9528
9521
[2 + 1] Cycloa d d ition Rea ction s of a 1-Selen o-2-silyleth en e to
2-Su lfon yla cr yla tes: Ster eoselective Syn th esis of
Su lfon e-Su bstitu ted Cyclop r op a n es
Shoko Yamazaki,* Yuichiro Yanase, Etsuko Tanigawa, and Shinichi Yamabe*
Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, J apan
Hatsue Tamura
Department of Applied Chemistry, Graduate School of Engineering, Osaka University,
1-16 Machikaneyama, Toyonaka, Osaka 560-0043, J apan
Received J uly 21, 1999
Reaction of 1-(phenylseleno)-2-(trimethylsilyl)ethene 1 and methyl or ethyl 2-p-toluene- or benzene-
sulfonylacrylates 3 in the presence of SnCl4 at -78 °C gave sulfone-substituted cyclopropanes 4 as
single stereoisomers. The structure of one of these crystalline cyclopropane products was elucidated
by X-ray crystallographic analysis. The relative stereochemistry of the cyclopropane ring carbon
(C2) and selenosilylmethyl group was determined as R,R and S,S, which is consistent with previous
mechanical considerations and the NOE determination. 2-Sulfinyl acrylate 2 did not undergo this
cycloaddition. The difference in reactivity of the sulfoxide 2 and sulfones 3 toward 1 was explained
by comparison of LUMO levels of 2-SnCl4 and 3-SnCl4 complexes and activation energies in the
synclinal addition of 1 to the complexes.
In tr od u ction
2-Sulfinylacrylates 2 and 2-sulfonylacrylates 3 were
expected to have high reactivity toward 1-seleno-2-
silylethene 1. They are isoelectronic analogues of meth-
ylenemalonate esters, which have been shown to have
effective reactivity toward 1.5b A different class of het-
eroatom analogues of methylenemalonates, 2-phospho-
noacrylates, have been found to be even better substrates.5e
The expected sulfur-substituted cyclopropane products
represent potentially versatile starting materials to ac-
cess biologically important compounds.6 Herein, we re-
port the stereoselective [2 + 1] cycloaddition of 1-seleno-
2-silylethene 1 to 2-sulfonylacrylates 3 leading to the
cyclopropanes 4. These products are crystalline, and the
structure of a cyclopropane product was determined by
X-ray crystallographic analysis. The relative stereochem-
istry of the cyclopropane ring carbon (C2) and selenosi-
lylmethyl group, which has not been unequivocally
elucidated directly so far in related cyclopropanes, was
determined as R,R and S,S. On the other hand, addition
did not occur in reactions between 1 and 2 (Scheme 1).
The crucial difference in the reactivities of 2 and 3 was
scrutinized by FMO analyses and ab initio calculations.
Organosulfur compounds have attracted much atten-
tion due to their synthetic usefulness and biological
interest.1,2 Among them, sulfones and sulfoxides have
been utilized for C-C bond formation as carbonyl group
equivalents for many synthetic transformations.1 In this
respect, unsaturated sulfones and sulfoxides are useful
Michael acceptors since they have strong electron-
withdrawing properties. Lewis acid-promoted reactions
of unsaturated sulfones and sulfoxides are also useful
since their oxygen atoms can coordinate to Lewis acids.3,4
We have recently reported a novel [2 + 1] cycloaddition
strategy involving reactions of (E)-1-(phenylseleno)-2-
silylethenes with electrophilic olefins to afford cyclopro-
pane products with high stereoselectivity in the presence
of Lewis acids.5 This new approach to cyclopropane
construction is based on a selenium-stabilized 1,2-silicon
migration process. As part of efforts to expand this novel
[2 + 1] cycloaddition reaction to electrophilic olefins with
synthetically and biologically useful substituents, we
became interested in sulfur-containing substrates.
(1) (a) Simpkins, N. S. Sulphones in Organic Synthesis; Pergamon
Press: Oxford, 1993. (b) Trost, B. M. Bull. Chem. Soc. J pn. 1988, 61,
107. (c) Magnus, P. D. Tetrahedron 1977, 33, 2019. (d) The Chemistry
of Sulphones and Sulphoxides; Patai, S., Rappoport, Z., Stirling, C. J .
M., Eds.; Wiley: New York, 1988.
Resu lts a n d Discu ssion
A. [2 + 1] Cycloa d d ition w ith 2-Su lfon yla cr yla tes.
Since Lewis acid-promoted reactions of R,â-unsaturated
(2) (a) Block, E. Reactions of Organosulfur Compounds; Academic
Press: New York, 1978. (b) Kjær, A. Pure Appl. Chem. 1977, 49, 137.
(c) The Chemistry of Sulfinic Acids, Esters, and their Derivatives; Patai,
S., Ed.; Wiley: New York, 1990. (d) The Chemistry of Sulfonic Acids,
Esters and their Derivatives; Patai, S., Rappoport, Z., Eds.; Wiley: New
York, 1991.
(3) (a) Alonso, I.; Carretero, J . C.; Garc´ıa Ruano, J . L. J . Org. Chem.
1993, 58, 3231. (b) Alonso, I.; Carretero, J . C.; Garc´ıa Ruano, J . L. J .
Org. Chem. 1994, 59, 1499. (c) Carren˜o, M. C.; Garc´ıa Ruano, J . L.;
Toledo, M. A.; Urbano, A.; Remor, C. Z.; Stefani, V. J . Org. Chem. 1996,
61, 503. (d) Arai, Y.; Matsui, M.; Koizumi, T.; Shiro, M. J . Org. Chem.
1991, 56, 1983. (e) Posner, G. H.; Frye, L. L.; Hulce, M. Tetrahedron
1984, 40, 1401. (f) Tietze, L. F.; Schuffenhauser, A.; Schreiner, P. R.
J . Am. Chem. Soc. 1998, 120, 7952.
(5) (a) Yamazaki, S.; Tanaka, M.; Yamaguchi, A.; Yamabe, S. J . Am.
Chem. Soc. 1994, 116, 2356. (b) Yamazaki, S.; Tanaka, M.; Inoue, T.;
Morimoto, N.; Kumagai, H.; Yamamoto, K. J . Org. Chem. 1995, 60,
6546. (c) Yamazaki, S.; Tanaka, M.; Yamabe, S. J . Org. Chem. 1996,
61, 4046. (d) Yamazaki, S.; Kumagai, H.; Takada, T.; Yamabe, S.;
Yamamoto, K. J . Org. Chem. 1997, 62, 2968. (e) Yamazaki, S.; Takada,
T.; Imanishi, T.; Moriguchi, Y.; Yamabe, S. J . Org. Chem. 1998, 63,
5919.
(6) For sulfur-containing biologically interesting cyclopropanes,
see: (a) Salau¨n, J .; Baird, M. S. Curr. Med. Chem. 1995, 2, 511. (b)
Gerwick, W. H.; Proteau, P. J .; Nagle, D. G.; Hamel, E.; Blokhin, A.;
Slate, D. L. J . Org. Chem. 1994, 59, 1243. (c) Clerici, F.; Gelmi, M. L.;
Pocar, D. J . Org. Chem. 1999, 64, 726. (d) Nakamura, H.; Ohtoshi,
M.; Sampei, O.; Akashi, Y.; Murai, A. Tetrahedron Lett. 1992, 33, 2821.
(4) Marcantoni, E.; Cingolani, S. J . Org. Chem. 1998, 63, 3624.
10.1021/jo9911591 CCC: $18.00 © 1999 American Chemical Society
Published on Web 12/01/1999

9522 J . Org. Chem., Vol. 64, No. 26, 1999
Yamazaki et al.
Sch em e 1
Sch em e 3
Sch em e 2
a
b
Isolated yield by column chromatogaphy. Isolated yield by
recrystallization. c 1 was recovered in 13% yield. d A small amount
of 1 remained but was not isolated.
Sch em e 4
sulfoxides have received much attention recently,3 we
initially attempted reaction of a sulfoxide analogue of
methylenemalonate, the 2-sulfinylacrylate 2,7 with 1.
However, reaction did not proceed in the presence of
SnCl4 and ZnBr2, which are the most effective Lewis acids
in this type of [2 + 1] cycloaddition reaction.5 Next,
reaction of the sulfone analogue 3 was attempted, since
sulfone groups are more electron-withdrawing than sul-
foxide groups, as suggested by Hammett constants and
the pKa of methyl sulfone and sulfoxide.8 The electronic
effect of the sulfone groups suggests higher reactivity of
2-sulfonylacrylates 3 toward 1. In addition, sulfone
groups often impart crystalline properties, which are
useful for purification and structure determination.
2-Arylsulfonylacrylates 3 were prepared by employing
known literature procedures for 2-alkylsulfonylacrylates
(Scheme 2).9 Although the difficulty of preparing pure
methyl 2-(phenylsulfonyl)acrylate has been pointed out,10
these 2-arylacrylates 3 were isolated in pure form by this
procedure.11
probably due to the instablity of 3 and the reaction
intermediates under the reaction conditions, leading to
formation of complex mixtures, including desilylated
products. In the case of reaction of 1 and 3c, desilylated
byproduct 8c was isolated in 14% yield. Using ZnBr2 as
a Lewis acid in the reaction of 1 and 3a resulted in
decomposition of 3a .
No reaction occurred between the donor olefin 1 and
the 3-substituted (E)-2-sulfonylacrylates 9 and 1012
under these reaction conditions, indicating synthetic
limitations.13 We also attempted the reaction of 1 with
R-sulfonyl-R,â-unsaturated ketone 11 under similar con-
ditions (SnCl4, -78 °C); however, the reaction gave a
complex mixture along with recovered 1 (41%). The
reaction of 1 and 11 in the presence of ZnI2 at -30 °C
for 5.5 h gave only the desilylated addition product
12 in 12% yield, and no cycloadduct was obtained
(Scheme 4).
B. Str u ctu r e Deter m in a tion of th e Cyclop r op a n es
4. The products 4a -c in Scheme 3 are crystalline and
easily purified by recrystallization. The cyclopropane
skeleton of 4a was determined by the characteristic 1J CH
values present in the 13C NMR spectrum (J ) 163-169
(C2) and 166-167 (C3) Hz).14 The stereochemistry in the
cyclopropane rings of 4a -c was readily deduced from the
2D-NOESY spectra. The NOE cross-peaks between H1
and o-H of SO2-Tol (o-H of SO2Ph) and between H2 and
The [2 + 1] cycloaddition reactions of 1 and 3 were
performed as follows (Scheme 3). Reactions of 1 (1 equiv)
and 2-sulfonylacrylates 3a -c (1.3 equiv) were carried out
in the presence of SnCl4 (1.5 equiv) in CH2Cl2 at -78 °C
for 3 h. Quenching with triethylamine (2.6 equiv) gave
[2 + 1] cycloadducts 4a -c as single stereoisomeric
products in 26-56% yields. The relatively low yields are
(7) (a) Leyendecker, F.; Comte, M.-T. Tetrahedron Lett. 1982, 25,
5031. (b) Yang, T.-K.; Teng, T.-F.; Lee, D.-S. J . Chin. Chem. Soc. 1991,
38, 375.
(8) (a) Szmant, H. H.; Suld, G. J . Am. Chem. Soc. 1956, 78, 3400.
(b) Matthews, W. S.; Bares, J . E.; Bartmess, J . E.; Bordwell, F. G.;
Cornforth, F. J .; Drucker, G. E.; Margolin, Z.; McCallum, R. J .;
McCollum, G. J .; Vanier, N. R. J . Am. Chem. Soc. 1975, 97, 7006.
(9) Gipstein, E.; Willson, C. G.; Sachdev, H. S. J . Org. Chem. 1980,
45, 1486.
(10) (a) Snider, B. B.; Phillips, G. B. J . Org. Chem. 1983, 48, 3685.
In the following references methyl 2-(phenylsulfonyl)acrylate appears;
however, the preparation was not described. (b) Pearson, A. J .;
Mortezaei, R. Tetrahedron Lett. 1989, 30, 5049. (c) Hirsenkon, R.;
Schmidt, R. R. Liebigs Ann. Chem. 1990, 883.
(12) 10 was prepared according to the literature procedure. Tani-
kaga, R.; Tamura, T.; Nozaki, Y.; Kaji, A. J . Chem. Soc., Chem.
Commun. 1984, 87.
(13) Under the reaction conditions, 10 was isomerized to a ca. 1:1
mixture of E/Z isomers, by 1H NMR of the reaction mixture. Due to
instability to column chromatography, the mixture could not be
isolated.
(11) 2-Arylsulfonylacrylates 3 were unstable to column chromatog-
raphy (SiO2).
(14) Stothers, J . B. Carbon-13 NMR Spectroscopy; Academic: New
York, 1972.

Synthesis of Sulfone-Substituted Cyclopropanes
J . Org. Chem., Vol. 64, No. 26, 1999 9523
Sch em e 5. P r op osed r ea ction m ech a n ism for
cyclop r op a n a tion (Th e Ca r bon Atom Nu m ber in g
Ad ju sts to Ch a r t 1)
F igu r e 1. ORTEP drawing of 4a (50% probability ellipsoids).
Selected bond lengths (Å) and torsion angle (deg): C1-C2 )
1.548(4); C1-C3 ) 1.532(4); C2-C3 ) 1.497(4); C1-S1 )
1.785(3); C1-C4 ) 1.495(4); C4-O1 ) 1.201(3); O2-C6 )
1.444(4); S1-O3 ) 1.443(2); S1-O4 ) 1.437(2); S1-C7 )
1.767(3); C2-C5 ) 1.510(4); C5-Se1 ) 1.982(3); C5-Si1 )
1.901(3); Se1-C14 ) 1.920(3); H1-C2-C5-H4 ) 172(2).
More detailed structure data are given in the Supporting
Information.
Ch a r t 1. Obser ved NOE’s (Atom Nu m ber in g Uses
Th a t of F igu r e 1)
mediate. The stereochemistry of the original addition step
is retained throughout this proposed mechanism, which
finally leads to the relative stereochemistry of C2, C5,
and C4.
C. Th eor etica l Stu d y on Rea ctivity of Su lfon es
a n d Su lfoxid es. The difference in the electrophilic effect
between the sulfone and sulfoxide groups (for example,
pKa Me2SO2 31.1, Me2SO 35.1)8b was initially thought to
be responsible for the different reactivity of 2 and 3.
However, this difference is insufficient to explain the
success or failure of the cyclopropanation reaction clearly.
The pronounced reactivity difference between 2 and 3
prompted us to investigate the reactive species according
to our proposed mechanism (Scheme 5). The lower
electrophilicity of the sulfoxide 2 compared to the sulfone
3a toward 1 may be explained by comparison of the
LUMO energy levels of 2-SnCl4 and 3a -SnCl4 complexes.
Unfortunately, little is known about the chemistry and
structure of sulfone-Lewis acid complexes compared to
those of carbonyl-Lewis acid complexes.15 We carried out
ab initio MO calculations for structures of complexes of
2 and 3a with SnCl4 using the LANL2MB method.16 All
ab initio molecular orbital calculations were performed
using the Gaussian 94 program package.17 First, geom-
etries of 2 and 3a were calculated (Figure S1 in the
Supporting Information). The LANL2MB-optimized S-O
distances (1.439 Å) of the sulfone 3a are in good agree-
ment with S-O distances (1.443, 1.437 Å) of the sulfone
4a by X-ray analysis. Chelate structures for 2-SnCl4 and
o-H of SO2Tol (o-H of SO2Ph) indicated that the CO2R
and CH(SePh)(SiMe3) groups were cis (Chart 1). Finally,
the structure of cyclopropane 4a was elucidated by single-
crystal X-ray analysis (Figure 1). Thus, the cis relation-
ship of the CO2R and CH(SePh)(SiMe3) groups was
confirmed, and the relative stereochemistry of the cyclo-
propane ring carbon (C2) and selenosilylmethyl group (C5)
in the racemic cyclopropane 4a was determined as R,R
and S,S.
In this series of novel cyclopropanation reactions of 1,
the relative stereochemistry of C2 and the selenosilyl-
methyl group has hitherto been determined by mechan-
ical considerations and by combination of the assumption
that H1-C2-C5-H4 is close to 180° and the observable
NOE’s in the examples reported so far.5b,d,e The relative
stereochemistry of C2 and C5 confirmed by X-ray is
consistent with the previous assignments of related
cyclopropanes.5 Also, the dihedral angle H1-C2-C5-
H4 observed in 4a was found to be 172°, which is in good
agreement with the above assumption.
The proposed reaction mechanism is similar to that
described previously, as shown in Scheme 5.5 Reaction
involves a synclinal stereoselective addition (due to a
stabilizing secondary orbital interaction, Se- - -CdO, not
Se- - -SO2Ar) and also involves a selenium-stabilized 1,2-
silicon migration in the resulting zwitterionic inter-
(15) Furukawa, N.; Fujiwara, H. In The Chemistry of Sulphones and
Sulphoxides; Patai, S., Rappoport, Z., Stirling, C. J . M., Eds.; Wiley:
1988; p 541.
(16) (a) Hay, P. J .; Wadt, W. R. J . Chem. Phys. 1985, 82, 270. (b)
Wadt, W. R.; Hay, P. J . J . Chem. Phys. 1985, 82, 284. (c) Hay, P. J .;
Wadt, W. R. J . Chem. Phys. 1985, 82, 299.

9524 J . Org. Chem., Vol. 64, No. 26, 1999
Yamazaki et al.
F igu r e 3. Frontier orbital coefficients of the LUMO of
2-SnCl4 and 3a -SnCl4 and HOMO of 1. These coefficients
are of STO-3G//LANL2MB.16,17 Bold upward arrows show the
most favorable orbital interaction leading to the synclinal-
addition path in Scheme 5 and Figure 4.
F igu r e 2. Ab initio RHF/LANL2MB-optimized geometries of
2-SnCl4 and 3a -SnCl4. Numbers in parentheses denote
atomic net charges of STO-3G//LANL2MB.
of 3a -SnCl4 and 2-SnCl4 are shown in Figure 3. They
indicate that the most electrophilic site in 3a -SnCl4 is
the C3 atom (+0.643) and that the coefficient of C4
(-0.566) is larger than that of the sulfur atom (-0.050).
The SnCl4 coordination is found to provide the combina-
tion of the largest C3, C4 coefficients suitable to the
synclinal orientation. Effective overlap of LUMO with the
HOMO of 1 controls the orientation in the synclinal
addition step, which leads to the transition-state geom-
etries (Figure 4) and the observed stereochemistry, as
discussed above (Scheme 5).
3a -SnCl4, which may be more stable than the corre-
sponding nonchelate structures, were successfully ob-
tained (Figure 2). Such Lewis acid-chelating properties
have been suggested in Lewis acid-catalyzed reactions
of â-carbonyl sulfoxides3 and sulfones.4
The transition states of the addition step between 3a -
SnCl4 and 2-SnCl4 complexes and 1 were next calculated
(Figure 4). Ea (activation energies) of addition between
2-SnCl4/3a -SnCl4 and 1 were obtained for both top side
and bottom side attack by 1. Then, the transition states
with the lower activation energies for each substrate were
compared.18 In accordance with the difference between
the LUMO energies of 2-SnCl4 and 3a -SnCl4, the Ea
value for 3a -SnCl4 (25.3 kcal/mol) is smaller than that
for 2-SnCl4 (26.9 kcal/mol for 2-SnCl4). Comparison of
both the LUMO levels of 2-SnCl4 and 3-SnCl4 com-
plexes and the activation energies in the synclinal
addition of 1 to the complexes explains the present
experimental results.19
The frontier orbital LUMOs of the complexes 2-SnCl4
and 3a -SnCl4 were calculated by STO-3G//LANL2MB.
As discussed previously, the LUMO levels of electro-
philic olefin-Lewis acid complexes are critical for high
reactivity.5d The LUMO level of 3a -SnCl4 (+0.09143 au)
was found to be substantially lower than that of 2-SnCl4
(+0.10019 au). Thus, the low LUMO energy level of 3a -
2SnCl4 causes a small HOMO-LUMO gap between 1 and
3a -Lewis acid complex, leading to a large charge-
transfer interaction (the upward bold arrows in Figure
3) and accordingly higher reactivity. The LUMO shapes
(18) The π-facial selectivity for Lewis acid-catalyzed reactions of
chiral 2-sulfinyl acrylates has been reported.3
(17) Frisch, M. J .; Trucks, G. W.; Schlegel, H. B.; Gill, P. M. W.;
J ohnson, B. G.; Robb, M. A.; Cheeseman, J . R.; Keith, T.; Petersson,
G. A.; Montgomery, J . A.; Raghavachari, K.; Al-Laham, M. A.;
Zakrzewski, V. G.; Ortiz, J . V.; Foresman, J . B.; Cioslowski, J .;
Stefanov, B. B.; Nanayakkara, A.; Challacombe, M.; Peng, C. Y.; Ayala,
P. Y.; Chen, W.; Wong, M. W.; Andres, J . L.; Replogle, E. S.; Gomperts,
R.; Martin, R. L.; Fox, D. J .; Binkley, J . S.; Defrees, D. J .; Baker, J .;
Stewart, J . J . P.; Head-Gordon, M.; Gonzalez, C.; Pople, J . A. Gaussian
94, Revision B.1; Gaussian, Inc.: Pittsburgh, PA, 1995. MO calculations
using Gaussian 94 were made on the CONVEX SPP1200/XA at the
Information Processing Center (Nara University of Education).
(19) In addition, we have examined alternative structures for the
3a -SnCl4 complex including a double SnCl4-coordinated structures20,21
by ab initio calculations. The result shows the remarkably low
activation energy of the addition step between 3a -2SnCl4 and 1. The
double SnCl4 coordination to 3a possibly gives rise to a highly enhanced
reactivity in the synclinal addition. The calculation results and the
discussion are presented in the Supporting Information.
(20) (a) Langford, C. H.; Langford, P. O. Inorg. Chem. 1962, 1, 184.
(b) Drago, R. S.; Wayland, B.; Carlson, R. L. J . Am. Chem. Soc. 1963,
85, 3125.

Synthesis of Sulfone-Substituted Cyclopropanes
J . Org. Chem., Vol. 64, No. 26, 1999 9525
F igu r e 4. (a) Ab initio RHF/LANL2MB-optimized geometries of transition states (TSs) for the addition step between 3a -SnCl4
and 1. The activation energy Ea is relative to those of reactants 3a -SnCl4 and 1. The atom numbering follows that in Figure 1.
Small white circles stand for hydrogen atoms. Ea’s of addition between 3a -SnCl4 and 1 are obtained for both top side and bottom
side attacks by 1. The transition states with the lower activation energies (underlined) were compared in the text. νq denotes a
sole imaginary frequency, which verifies that the obtained geometry is correctly of the saddle point. (b) Ab initio RHF/LANL2MB-
optimized geometries of transition states (TSs) for the addition step between 2-SnCl4 and 1. The activation energy Ea is relative
to those of reactants 2-SnCl4 and 1. Ea’s of addition between 2-SnCl4 and 1 are obtained for both top side and bottom side
attacks by 1. The transition states with the lower activation energies (underlined) were compared in the text.
Con clu d in g Rem a r k s
acids. We are further investigating heteroatom-based
effective electrophilic olefins for the [2 + 1] cycloaddition
reactions of 1, leading to biologically interesting com-
pounds.
We have shown that 1-seleno-2-silylethene 1 and
2-sulfonylacrylates 3 undergo SnCl4-promoted [2 + 1]
cycloaddition reactions stereoselectively. The products
are crystalline, and the structure of a cyclopropane
product was elucidated by X-ray crystallographic analysis
for the first time in this series of [2 + 1] cycloaddition
reactions. The relative stereochemistry of the cyclopro-
pane ring carbon C2 and selenosilylmethyl group was
unambiguously determined as R,R and S,S, which is
consistent with the previous assignment of the cyclopro-
pane products. The difference in the reactivity between
the sulfoxide 2 and the sulfone 3 was explained by
comparison of LUMO levels of 2-SnCl4 and 3-SnCl4
complexes and activation energies in the synclinal addi-
tion of 1 to the complexes.
Exp er im en ta l Section
Gen er a l Meth od s. Melting points are uncorrected. IR
1
spectra were recorded in the FT-mode. H NMR spectra were
recorded at 400 MHz. 13C NMR spectra were recorded at 100.6
MHz. Chemical shifts are reported in ppm relative to Me4Si
or residual nondeuterated solvent. Mass spectra were recorded
at an ionizing voltage of 70 eV by EI or FAB. All reactions
were carried out under a nitrogen atmosphere.
Meth yl 2-(p-Tolu en esu lfon yl)p r op a n a te (6a ). A solution
of p-toluenesulfinic acid, sodium salt hydrate (12.5 g, 50.0
mmol), methyl 2-chloropropionate (5.7 mL, 6.13 g, 50.0 mmol),
and ethanol (25 mL) was refluxed for 24 h. The solution was
filtered to remove sodium chloride and concentrated under
reduced pressure. The residue was purified by column chro-
matography over silica gel eluting with CH2Cl2 to give 6a (8.20
Although the yields in this [2 + 1] cycloaddition
reaction of 2-sulfonylacrylates 3 are not high, the reasc-
tion represents a new usage of 3 in the presence of Lewis
1
g, 68%) (Rf ) 0.3): colorless crystals; mp 49-52 °C; H NMR
(400 MHz, CDCl3) δ (ppm) 1.55 (d, J ) 7.1 Hz, 3H), 2.46 (s,
3H), 3.70 (s, 3H), 4.07 (q, J ) 7.1 Hz, 1H), 7.37 (d-like, J ) 8.5
Hz, 2H), 7.75 (d-like, J ) 8.5 Hz, 2H); 13C NMR (100.6 MHz,
(21) For examples of chlorine-bridged tin(IV) complexes and 4-8
coordinated tin(IV) complexes, see: Harrison, R. G. In Chemistry of
Tin; Harrison, R. G., Ed.; Blackie: Glasgow, 1989; p 9.

9526 J . Org. Chem., Vol. 64, No. 26, 1999
Yamazaki et al.
CDCl3) δ (ppm) 12.06 (q), 21.77 (q), 53.04 (q), 65.44 (d), 129.4
(d), 129.8 (d), 133.8 (s), 145.5 (s), 166.9 (s); IR (KBr) 1742, 1601,
1317, 1139 cm-1; MS (EI) m/z 242; exact mass M+ 242.0620
(calcd for C11H14O4S 242.0613). Anal. Calcd for C11H14O4S: C,
54.53; H, 5.82. Found: C, 54.24; H, 5.79.
Eth yl 2-(p-tolu en esu lfon yl)p r op a n a te (6b): yield 95%;
Rf ) 0.2 (CH2Cl2; colorless crystals; mp 38-40 °C (hexane-
ether); 1H NMR (400 MHz, CDCl3) δ (ppm) 1.19 (t, J ) 7.1
Hz, 3H), 1.55 (d, J ) 7.1 Hz, 3H), 2.46 (s, 3H), 4.02 (q, J ) 7.1
Hz, 1H), 4.13 (q, J ) 7.1 Hz, 2H), 7.36 (d-like, J ) 8.4 Hz,
2H), 7.76 (d-like, J ) 8.4 Hz, 2H); 13C NMR (100.6 MHz,
CDCl3) δ (ppm) 11.96 (q), 13.92 (q), 21.77 (q), 62.28 (t), 65.53
(d), 129.5 (d), 129.7 (d), 134.0 (s), 145.4 (s), 166.4 (s); IR (KBr)
1740, 1597, 1325, 1150 cm-1; MS (EI) m/z 256; exact mass M+
256.0760 (calcd for C12H16O4S 256.0769). Anal. Calcd for
1145 cm-1; MS (EI) m/z 398; exact mass M+ 398.0108 (calcd
for C17H18O4SSe 398.0091). Anal. Calcd for C17H18O4SSe: C,
51.39; H, 4.57. Found: C, 51.49; H, 4.39.
Meth yl 2-(p-Tolu en esu lfon yl)a cr yla te (3a ). To a solution
of 7a (1.5 g, 3.8 mmol) in dichloromethane (7.3 mL) was added
H2O2 (30% 2.9 mL, 25.2 mmol) in water (6 mL) at 0 °C. The
reaction mixture was stirred at room temperature for 1 h. The
reaction mixture was washed with saturated NaHCO3 in CH2-
Cl2. The organic layer was separated and dried (Na2SO4).
Removal of the solvent in vacuo gave 3a (0.95 g, 100%):
colorless crystals; mp 75-77 °C (hexane-ethyl acetate); 1H
NMR (400 MHz, CDCl3) δ (ppm) 2.44 (s, 3H), 3.74 (s, 3H), 6.98
(s, 1H), 7.12 (s, 1H), 7.34 (d-like, J ) 8.1 Hz, 2H), 7.86 (d-like,
J ) 8.1 Hz, 2H); 13C NMR (100.6 MHz, CDCl3) δ (ppm) 21.77
(q), 52.85 (q), 129.2 (d), 129.7 (d), 136.1 (s), 137.2 (t), 143.6 (s),
145.0 (s), 161.0 (s); IR (KBr) 1729, 1597, 1321, 1154 cm-1; MS
(EI) m/z 240; exact mass M+ 240.0447 (calcd for C11H12O4S
240.0456). Anal. Calcd for C11H12O4S: C, 54.99; H, 5.03; S,
13.35. Found: C, 54.78; H, 4.98; S, 13.26.
Eth yl 2-(p-tolu en esu lfon yl)a cr yla te (3b): yield 78%;
colorless crystals; mp 44-45 °C (hexane-ether); 1H NMR (400
MHz, CDCl3) δ (ppm) 1.23 (t, J ) 7.1 Hz, 3H), 2.44 (s, 3H),
4.19 (q, J ) 7.1 Hz, 2H), 6.98 (s, 1H), 7.11 (s, 1H), 7.33 (d-like,
J ) 8.5 Hz, 2H), 7.85 (d-like, J ) 8.5 Hz, 2H); 13C NMR (100.6
MHz, CDCl3) δ (ppm) 13.95 (q), 21.76 (q), 62.28 (t), 129.1 (d),
129.6 (d), 136.2 (s), 137.1 (t), 143.8 (s), 145.0 (s), 160.5 (s); IR
(KBr) 1721, 1597, 1323, 1158 cm-1; MS (EI) m/z 254; exact
mass M+ 254.0622 (calcd for C12H14O4S 254.0613). Anal. Calcd
for C12H14O4S: C, 56.68; H, 5.55. Found: C, 56.71; H, 5.53.
Eth yl 2-(ben zen esu lfon yl)a cr yla te (3c): yield 89%; pale
yellow oil; 1H NMR (400 MHz, CDCl3) δ (ppm) 1.21 (t, J ) 7.1
Hz, 3H), 4.18 (q, J ) 7.1 Hz, 2H), 7.02 (s, 1H), 7.14 (s, 1H),
7.52-7.57 (m, 2H), 7.64 (t-like, J ) 7.4 Hz, 1H), 7.98 (d-like,
J ) 8.4 Hz, 2H); 13C NMR (100.6 MHz, CDCl3) δ (ppm) 13.87
(q, J ) 128 Hz), 62.28 (t, J ) 150 Hz), 128.9 (d, J ) 165 Hz),
129.0 (d, J ) 165 Hz), 129.1 (s), 133.8 (d, J ) 161 Hz), 137.5
(t, J ) 167 Hz), 139.2 (s), 143.5 (s), 160.3 (s); IR (neat) 1729,
1615, 1323, 1162 cm-1; MS (EI) m/z 240; exact mass M+
240.0451 (calcd for C11H12O4S 240.0456).
C
12H16O4S: C, 56.23; H, 6.29. Found: C, 56.20; H, 6.35.
Eth yl 2-(ben zen esu lfon yl)p r op a n a te (6c): yield 76%; Rf
) 0.3 (CH2Cl2); colorless oil; 1H NMR (400 MHz, CDCl3) δ
(ppm) 1.17 (t, J ) 7.1 Hz, 3H), 1.58 (d, J ) 7.1 Hz, 3H), 4.05
(q, J ) 7.1 Hz, 1H), 4.115 (q, J ) 7.1 Hz, 1H), 4.117 (q, J )
7.1 Hz, 1H), 7.56-7.60 (m, 2H), 7.67-7.72 (m, 1H), 7.89-7.92
(m, 2H); 13C NMR (100.6 MHz, CDCl3) δ (ppm) 11.82 (q), 13.90
(q), 62.31 (t), 65.48 (d), 129.1 (d), 129.4 (d), 134.3 (d), 137.1
(s), 166.3 (s); IR (KBr) 1734, 1586, 1320, 1147 cm-1; MS (EI)
m/z 243 (M+ + 1). Anal. Calcd for C11H14O4S: C, 54.53; H, 5.82.
Found: C, 54.26; H, 6.00.
Meth yl 2-(P h en ylselen o)-2-(p-tolu en esu lfon yl)p r op a n -
a te (7a ). Sodium hydride (222 mg, 60% dispersion in oil, 5.55
mmol, washed three times with pentane) was suspended in
freshly distilled THF (6.9 mL). After the mixture was cooled
to -10 °C, methyl 2-(p-toluenesulfonyl)propanate (6a ) (1.34
g, 5.53 mmol) in THF (2.3 mL) was added dropwise, and the
mixture was cooled to -20 °C and stirred for 2 h. Phenylselenyl
bromide [5.54 mmol, prepared by adding bromine (0.14 mL,
443 mg, 2.77 mmol) to a stirred solution of diphenyl diselenide
(865 mg, 2.77 mmol) in THF (3.5 mL) at room temperature
followed by further stirring for 10 min] was then added. After
2 h at -20 °C, the mixture was allowed to warm to room
temperature. The mixture was treated with
a saturated
solution of NH4Cl (0.46 mL), and THF was removed under
reduced pressure. The residue was extracted with three
portions of ether. The combined ether extracts were washed
with brine and dried (MgSO4). The solvent was evaporated in
vacuo. The residue was purified by column chromatography
over silica gel eluting with hexane-ether (1:1) to give 7a (1.54
g, 70%): Rf ) 0.4; colorless crystals; mp 102-105 °C; 1H NMR
(400 MHz, CDCl3) δ (ppm) 1.63 (s, 3H), 2.45 (s, 3H), 3.64 (s,
3H), 7.30-7.35 (m, 4H), 7.43 (t-like, J ) 7.4 Hz, 1H), 7.71 (d-
like, J ) 8.2 Hz, 2H), 7.82 (d, J ) 8.4 Hz, 2H); 13C NMR (100.6
MHz, CDCl3) δ (ppm) 20.10, 21.71, 53.25, 71.08, 125.8, 129.0,
129.2, 130.2, 130.9, 132.7, 138.6, 145.4, 167.4; IR (KBr) 1740,
1597, 1299, 1137 cm-1; MS (EI) m/z 398; exact mass M+
398.0161 (calcd for C17H18O4SSe 398.0092). Anal. Calcd for
Meth yl r -1-(p-Tolu en esu lfon yl)-c-2-[(p h en ylselen o)-
(tr im eth ylsilyl)m eth yl]-1-cyclop r op a n eca r boxyla te (4a ).
To a solution of 1 (255 mg, 1.0 mmol) in dichloromethane (2.4
mL) was added SnCl4 (0.173 mL, 391 mg, 1.5 mmol) followed
by 2-sulfonylacrylate 3a (312 mg, 1.3 mmol) at -78 °C. The
mixture was stirred at -78 °C for 3 h. The reaction mixture
was quenched by triethylamine (0.32 mL, 230 mg, 2.3 mmol)
and then saturated aqueous NaHCO3. The mixture was
extracted with dichloromethane, and the organic phase was
washed with water, dried (Na2SO4), and evaporated in vacuo.
The residue was purified by column chromatography over silica
gel eluting with hexane-ether (2:1) to give 4a (278 mg, 56%)
(Rf ) 0.3). An analytically pure sample was recrystallized from
hexanes-ether: colorless crystals; mp 117-119 °C (hexanes-
ether); 1H NMR (400 MHz, CDCl3) δ (ppm) 0.146 (s, 9H,
SiMe3), 1.78 (dd, J ) 8.4, 5.1 Hz, 1H, H3), 2.39 (dd, J ) 9.8,
5.1 Hz, 1H, H2), 2.48 (s, 3H, C6H4-p-Me), 2.49 (d, J ) 12.4 Hz,
1H, H4), 2.63 (ddd, J ) 12.4, 9.8, 8.4 Hz, 1H, H1), 3.20 (s, 3H,
OMe), 7.06-7.19 (m, 5H, SePh), 7.37 (d, J ) 8.2 Hz, 2H, m-H
of SO2-Tol), 7.88 (d, J ) 8.2 Hz, 2H, o-H of SO2-Tol) (see
numbering in Chart 1); selected NOEs in the 2D-NOESY
spectra were between δ 1.78 and 2.49, δ 2.39 and 2.63, δ 2.39
C
17H18O4SSe: C, 51.39; H, 4.57. Found: C, 51.19; H, 4.44.
Eth yl 2-(p h en ylselen o)-2-(p-tolu en esu lfon yl)p r op a n -
a te (7b): yield 93%; Rf ) 0.2 (hexane/ether ) 2:1); colorless
1
crystals; mp 88-91 °C; H NMR (400 MHz, CDCl3) δ (ppm)
1.20 (t, J ) 7.1 Hz, 3H), 1.63 (s, 3H), 2.46 (s, 3H), 4.09 (q, J )
7.1 Hz, 2H), 7.31-7.35 (m, 4H), 7.43 (t-like, J ) 7.4 Hz, 1H),
7.73 (d-like, J ) 8.2 Hz, 2H), 7.84 (d, J ) 8.2 Hz, 2H); 13C
NMR (100.6 MHz, CDCl3) δ (ppm) 13.82 (q), 20.11 (q), 21.80
(q), 62.91 (t), 71.19 (s), 126.0 (s), 129.0 (d), 129.2 (d), 130.3 (d),
131.2 (d), 132.9 (s), 138.7 (d), 145.4 (s), 167.1 (s); IR (KBr) 1736,
1595, 1300, 1139 cm-1; MS (EI) m/z 412; exact mass M+
412.0208 (calcd for C18H20O4SSe 412.0247). Anal. Calcd for
1
and 7.88, δ 2.63 and 7.88; H assignments were determined
by H-H COSY and NOESY; 13C NMR (100.6 MHz, CDCl3) δ
(ppm) -1.894 (q, J ) 120 Hz), 21.73 (qt, J ) 127, 4.4 Hz),
24.61 (t, J ) 166 Hz, C3), 28.81 (d, J ) 137 Hz, C5), 36.33 (dd,
J ) 166, 6.5 Hz, C2), 50.53 (s, C1), 52.40 (q, J ) 148 Hz), 127.3
(dt, J ) 160, 7.4 Hz), 128.7 (dd, J ) 161, 7.2 Hz), 129.2 (d, J
) 162 Hz), 129.8 (d, J ) 166, 5.7 Hz), 130.3 (s), 134.1 (dt, J )
163, 6.7 Hz), 137.2 (s), 144.5 (s), 166.1 (s, C4); 13C assignments
were determined by HMQC and HMBC; IR (KBr) 1730, 1599,
1310, 1143 cm-1; MS (EI) m/z 496; exact mass M+ 496.0622
(calcd for C22H28O4SSeSi 496.0643). Anal. Calcd for C22H28O4-
SSeSi: C, 53.32; H, 5.69. Found: C, 53.27; H, 5.58.
C
18H20O4SSe: C, 52.55; H, 4.90. Found: C, 52.35; H, 4.69.
Eth yl 2-(ben zen esu lfon yl)-2-(p h en ylselen o)p r op a n a te
(7c): yield 66%; Rf ) 0.2 (hexane/ether ) 2:1); colorless
1
crystals; mp 56-58 °C; H NMR (400 MHz, CDCl3) δ (ppm)
1.17 (t, J ) 7.1 Hz, 3H), 1.65 (s, 3H), 4.07 (q, J ) 7.1 Hz, 2H),
7.32 (t, J ) 7.5 Hz, 2H), 7.43 (t, J ) 7.4 Hz, 1H), 7.55 (t, J )
7.8 Hz, 2H), 7.66-7.72 (m, 3H), 7.98 (d, J ) 8.3 Hz, 2H); 13C
NMR (100.6 MHz, CDCl3) δ (ppm) 13.73 (q), 20.02 (q), 62.89
(t), 71.17 (s), 125.9 (s), 128.5 (d), 129.0 (d), 130.3 (d), 131.1 (d),
134.2 (d), 135.9 (s), 138.6 (d), 166.8 (s); IR (KBr) 1738, 1305,
Eth yl r -1-(p-tolu en esu lfon yl)-c-2-[(p h en ylselen o)(tr i-
m eth ylsilyl)m eth yl]-1-cyclopr opan ecar boxylate (4b): yield

Synthesis of Sulfone-Substituted Cyclopropanes
J . Org. Chem., Vol. 64, No. 26, 1999 9527
34% after purification by recrystallization from hexane-
ether) (Rf ) 0.3); colorless crystals; mp 89-90 °C; 1H NMR
(400 MHz, CDCl3) δ (ppm) 0.137 (s, 9H), 1.01 (t, J ) 7.1 Hz,
3H), 1.79 (dd, J ) 8.1, 5.0 Hz, 1H, H3), 2.40 (dd, J ) 9.6, 5.0
Hz, 1H, H2), 2.48 (s, 3H), 2.55 (d, J ) 12.5 Hz, 1H, H4), 2.63
(ddd, J ) 12.5, 9.6, 8.1 Hz, 1H, H1), 3.44 (dq, J ) 10.8, 7.2 Hz,
1H), 3.77 (dq, J ) 10.8, 7.2 Hz, 1H), 7.06-7.16 (m, 3H), 7.18-
7.21 (m, 2H), 7.36 (d, J ) 8.4 Hz, 2H), 7.89 (d, J ) 8.4 Hz,
2H); selected NOEs were between δ 1.79 and 2.55, δ 2.40 and
2.63, δ 2.40 and 7.89, δ 2.63 and 7.89; 13C NMR (100.6 MHz,
CDCl3) δ (ppm) -1.872 (q, J ) 120 Hz), 13.66 (q, J ) 127 Hz),
21.76 (qt, J ) 124, 4.4 Hz), 24.52 (t, J ) 166 Hz, C3), 28.53 (d,
J ) 137 Hz, C5), 36.20 (d, J ) 169 Hz, C2), 50.34 (s, C1), 62.23
(t, J ) 149 Hz), 127.2 (dt, J ) 161, 7.4 Hz), 128.7 (dd, J )
161, 7.2 Hz), 129.1 (d, J ) 161 Hz), 129.8 (dd, J ) 166, 5.3
Hz), 130.4 (s), 133.9 (dt, J ) 163, 6.9 Hz), 137.2 (t, J ) 8.4
Hz), 144.5 (s), 165.7 (s, C4); IR (KBr) 1719, 1599, 1323, 1145
cm-1; MS (EI) m/z 510; exact mass M+ 510.0815 (calcd for
min. After 1 h, methyl bromoacetate (1.37 g, 8.92 mmol) was
added, and the mixture was stirred for 12 h at 20 °C. The
mixture was extracted with ether, and the ether extracts were
washed with saturated NH4Cl solution and saturated sodium
chloride solution and dried (MgSO4). The solvent was evapo-
rated in vacuo. The residue was purified by column chroma-
tography over silica gel eluting with ether-hexane (2:1) to give
the title compound (1.84 g, 66%) (Rf ) 0.4): colorless crystals;
mp 63-65 °C; 1H NMR (400 MHz, CDCl3) δ (ppm) 1.16 (t,
J ) 7.1 Hz, 3H), 2.47 (s, 3H), 3.06-3.18 (m, 2H), 3.69 (s, 3H),
4.07-4.19 (m, 2H), 4.40 (dd, J ) 9.7, 5.3 Hz, 1H), 7.38 (d-like,
J ) 8.2 Hz, 2H), 7.76 (d-like, J ) 8.2 Hz, 2H); 13C NMR
(100.6 MHz, CDCl3) δ (ppm) 13.82 (q), 21.78 (q), 31.05 (t),
52.49 (q), 62.59 (t), 66.46 (d), 129.2 (d), 129.9 (d), 134.3 (s),
145.8 (s), 165.0 (s), 170.2 (s); IR (KBr) 1738, 1597, 1323,
1151 cm-1; MS (FAB) m/z 315 (MH+). Anal. Calcd for
C
14H18O6S: C, 53.49; H, 5.77; S, 10.20. Found: C, 53.39; H,
5.75; S, 10.13.
C
23H30O4SSeSi 510.0799). Anal. Calcd for C23H30O4SSeSi: C,
1-Eth yl 4-m eth yl 2-(p h en ylselen o)-2-(p-tolu en esu lfo-
n yl)eth a n e-1,2-d ica r boxyla te (in ter m ed ia te for 9): yield
45%; Rf ) 0.4 (hexane/ether ) 3:1); colorless crystals; mp 108-
54.21; H, 5.93. Found: C, 54.16; H, 5.80.
Eth yl r -1-(ben zen esu lfon yl)-c-2-[(p h en ylselen o)(tr i-
m eth ylsilyl)-m eth yl]-1-cyclopr opan ecar boxylate (4c): yield
26%; Rf ) 0.3 (hexane-ether ) 2:1); colorless crystals; mp
108-110 °C (cyclohexane-ether); 1H NMR (400 MHz, CDCl3)
δ (ppm) 0.150 (s, 9H), 0.967 (t, J ) 7.2 Hz, 1H), 1.81 (dd, J )
8.3, 5.1 Hz, 1H, H3), 2.42 (dd, J ) 9.8, 5.1 Hz, 1H, H2), 2.55 (d,
J ) 12.5 Hz, 1H, H4), 2.65 (ddd, J ) 12.5, 9.8, 8.3 Hz, 1H, H1),
3.39 (dq, J ) 10.5, 7.3 Hz, 1H), 3.74 (dq, J ) 10.5, 7.3 Hz),
7.06-7.18 (m, 5H), 7.55-7.60 (m, 2H), 7.68 (t-like, J ) 7.5
Hz, 1H), 8.03 (d-like, J ) 7.1 Hz, 2H). Selected NOE’s were
between δ 1.81 and 2.55, δ 2.42 and 2.65, δ 2.42 and 8.03, δ
2.65 and 8.03.; 13C NMR (100.6 MHz, CDCl3) δ (ppm) -1.879
(q, J ) 120 Hz), 13.60 (q, J ) 128 Hz), 24.44 (t, J ) 167 Hz,
C3), 28.57 (d, J ) 136 Hz, C5), 36.51 (d, J ) 163 Hz, C2), 50.25
(s, C1), 62.25 (t, J ) 149 Hz), 127.2 (d, J ) 162 Hz), 128.5 (d,
J ) 161 Hz), 128.7 (d, J ) 161 Hz), 129.8 (d, J ) 167 Hz),
130.4 (s), 133.5 (d, J ) 164 Hz), 133.8 (d, J ) 164 Hz), 140.2
(s), 165.5 (s, C4); IR (KBr) 1719, 1317, 1143 cm-1; MS (EI) m/z
496; exact mass M+ 496.0707 (calcd for C22H28O4SSeSi
496.0643). Anal. Calcd for C22H28O4SSeSi: C, 53.32; H, 5.69.
Found: C, 53.26; H, 5.51.
Eth yl (E)-2-(ben zen esu lfon yl)-5-(p h en ylselen o)-4-p en -
t en oa t e (8c): Rf ) 0.2 (hexane-ether ) 2:1); colorless
crystals; mp 52-54 °C (cyclohexane-ether); 1H NMR (400
MHz, CDCl3) δ (ppm) 1.13 (t, J ) 7.1 Hz, 3H), 2.74-2.90 (m,
2H), 3.99 (dd, J ) 11.1, 4.1 Hz, 1H), 4.05-4.13 (m, 2H), 5.76
(ddd, J ) 15.2, 7.7, 6.8 Hz, 1H), 6.55 (dt, J ) 15.2, 1.2 Hz,
1H), 7.25-7.30 (m, 3H), 7.39-7.44 (m, 2H), 7.57 (t-like, J )
7.7 Hz, 2H), 7.69 (t-like, 7.4 Hz, 1H), 7.88 (d-like, J ) 8.4 Hz,
2H); 13C NMR (100.6 MHz, CDCl3) δ (ppm) 13.98 (q), 31.41
(t), 62.42 (t), 69.85 (d), 123.4 (d), 127.6 (d), 129.1 (d), 129.2
(d), 129.40 (d), 129.42 (d), 129.6 (s), 132.6 (d), 134.5 (d), 137.2
(s), 165.2 (s); IR (KBr) 1727, 1657, 1313, 1156 cm-1; MS (EI)
m/z 424. Anal. Calcd for C19H20O4SSe: C, 53.90; H, 4.76.
Found: C, 53.72; H, 4.63.
1-Eth yl 4-Meth yl (E)-2-(p-Tolu en esu lfon yl)eth en e-1,2-
d ica r boxyla te (9). Prepared from 1-ethyl 4-methyl 2-(p-
toluenesulfonyl)ethane-1,2-dicarboxylate described below, by
the same procedure for 3 (phenylselenylation (45%) and
oxidation (100%)) (E/Z ) 9:1): colorless oil; 1H NMR (400 MHz,
CDCl3) for the major E isomer δ (ppm) 1.25 (t, J ) 7.1 Hz,
3H), 2.46 (s, 3H), 3.80 (s, 3H), 4.26 (q, J ) 7.1 Hz, 2H), 7.09
(s, 1H), 7.36 (bd, J ) 8.1 Hz, 2H), 7.79 (bd, J ) 8.1 Hz, 2H);
selected NOE was between δ 7.09 (olefin-H) and 7.79 (o-H of
p-tolyl); 13C NMR (100.6 MHz, CDCl3) for major isomer δ (ppm)
13.78 (q), 21.81 (q), 52.95 (q), 62.96 (t), 129.2 (d), 130.0 (d),
130.7 (d), 134.9 (s), 146.0 (s), 147.7 (s), 161.0 (s), 163.3 (s); IR
(neat) 1734, 1636, 1330, 1156 cm-1; MS (EI) m/z 312; exact
mass M+ 312.0667 (calcd for C14H16O6S 312.0668).
1-Eth yl 4-Meth yl 2-(p-Tolu en esu lfon yl)eth a n e-1,2-d i-
ca r boxyla te (In ter m ed ia te for 9). Sodium hydride (392 mg,
60% dispersion in oil, 9.80 mmol, washed three times with
pentane) was suspended in freshly distilled THF (9.0 mL).
After the mixture was cooled to 0 °C, ethyl 2-(p-toluenesulfo-
nyl)acetate (2.16 g, 8.92 mmol) was added dropwise over 10
1
110 °C; H NMR (400 MHz, CDCl3) δ (ppm) 1.20 (t, J ) 7.1
Hz, 3H), 2.46 (s, 3H), 2.68 (d, J ) 17.7 Hz, 1H), 3.40 (d, J )
17.7 Hz, 1H), 3.56 (s, 3H), 4.11-4.19 (m, 2H), 7.31-7.35 (m,
4H), 7.44 (t-like, J ) 7.4 Hz, 1H), 7.77-7.81 (m, 4H); 13C NMR
(100.6 MHz, CDCl3) δ (ppm) 13.72 (q), 21.82 (q), 36.08 (t), 52.08
(q), 63.37 (t), 74.82 (s), 125.6 (s), 128.9 (d), 129.3 (d), 130.4 (d),
131.2 (d), 132.0 (s), 139.0 (d), 145.7 (s), 165.7 (s), 168.6 (s); IR
(KBr) 1735, 1597, 1357, 1151 cm-1; MS (EI) m/z 470.
Eth yl (E)-2-(p-Tolu en esu lfon yl)cin n a m a te (10). Pre-
pared from ethyl 2-(p-toluenesulfonyl)acetate and benzalde-
hyde according to the literature procedure:12 yield 24%;
colorless crystals; mp 68 °C (hexane-ether); 1H NMR (400
MHz, CDCl3) δ (ppm) 1.16 (t, J ) 7.1 Hz, 3H), 2.44 (s, 3H),
4.22 (q, J ) 7.1 Hz, 2H), 7.33-7.45 (m, 7H), 7.83 (d-like, J )
8.4 Hz, 2H), 7.94 (s, 1H). Selected NOE’s were between δ 4.22
(OCH2) and around 7.45 (o-Ph) and δ 7.83 (olefin-H) and 7.94
(o-H of p-tolyl).; 13C NMR (100.6 MHz, CDCl3) δ (ppm) 13.70
(q), 21.77 (q), 62.44 (t), 128.7 (d), 128.9 (d), 129.8 (d), 129.9
(d), 131.4 (d), 131.8 (s), 135.4 (s), 137.0 (s), 143.3 (d), 144.8 (s),
163.3 (s); IR (neat) 1723, 1624, 1325, 1152 cm-1; MS (EI) m/z
330; exact mass M+ 330.0924 (calcd for C18H18O4S 330.0925).
Anal. Calcd for C18H18O4S: C, 65.43; H, 5.49. Found: C, 65.34;
H, 5.42.
1-P h en yl-2-(p-tolu en esu lfon yl)-2-pr open -1-on e (11). Pre-
pared by reaction of p-toluenesulfinic acid, sodium salt hy-
drate, and methyl 2-bromopropiophenone in refluxing ethanol
(71%) and then the same procedure for 3 (phenylselenylation
(68%) and oxidation (60%)): colorless crystals; mp 107-109
1
°C; H NMR (400 MHz, CDCl3) δ (ppm) 2.45 (s, 3H), 6.27 (d,
J ) 0.9 Hz, 1H), 7.09 (d, J ) 0.9 Hz, 1H), 7.35 (d, J ) 8.1 Hz,
2H), 7.46 (t, J ) 7.9 Hz, 2H), 7.61 (t-like, J ) 7.5 Hz, 2H),
7.81 (d-like, J ) 7.9 Hz, 2H), 7.85 (d-like, J ) 8.4 Hz, 2H); 13
C
NMR (100.6 MHz, CDCl3) δ (ppm) 21.80 (q), 128.8 (d), 129.0
(d), 129.8 (d), 130.0 (d), 132.2 (t), 134.2 (d), 136.0 (s), 136.6 (s),
145.1 (s), 149.7 (s), 190.2 (s); IR (KBr) 1663, 1595, 1321, 1141
cm-1; MS (EI) m/z 286; exact mass M+ 286.0662 (calcd for
C
16H14O3S 286.0664). Anal. Calcd for C16H14O3S: C, 67.11;
H,4.93. Found: C, 66.66; H, 4.83.
2-(p-Tolu en esu lfon yl)pr opioph en on e (in ter m ediate for
11): yield 71%, purified by recrystallization from ethyl acetate;
colorless crystals; mp 97-100 °C; 1H NMR (400 MHz, CDCl3)
δ (ppm) 1.56 (d, J ) 6.9 Hz, 3H), 2.44 (s, 3H), 5.15 (q, J ) 6.9
Hz, 1H), 7.31 (d-like, J ) 8.1 Hz, 2H), 7.48 (t-like, J ) 7.7 Hz,
2H), 7.59-7.63 (m, 1H), 7.66 (d-like, J ) 8.2 Hz, 2H), 7.97-
8.00 (m, 2H); 13C NMR (100.6 MHz, CDCl3) δ (ppm) 13.32 (q),
21.78 (q), 65.07 (d), 128.8 (d), 129.3 (d), 129.6 (d), 129.9 (d),
133.0 (s), 134.1 (d), 136.3 (s), 145.4 (s), 192.7 (s); IR (KBr) 1678,
1315, 1151 cm-1; MS (EI) m/z 288; exact mass M+ 288.0761
(calcd for C16H16O3S 288.0820). Anal. Calcd for C16H16O3S: C,
66.64; H, 5.59. Found: C, 66.36; H, 5.59.
2-(P h e n ylse le n o)-2-(p -t olu e n e su lfon yl)p r op iop h e -
n on e (in ter m ed ia te for 11): yield 68%, including a small
amount of impurity; Rf ) 0.4 (hexane-ether ) 1:1); pale yellow
1
oil; H NMR (400 MHz, CDCl3) δ (ppm) 1.62 (s, 3H), 2.42 (s,

9528 J . Org. Chem., Vol. 64, No. 26, 1999
Yamazaki et al.
3H), 7.27 (d, J ) 8.2 Hz, 2H), 7.31 (d, J ) 7.7 Hz, 2H), 7.41
(t-like, J ) 7.5 Hz, 1H), 7.45 (t-like, J ) 7.7 Hz, 2H), 7.56 (t-
like, J ) 7.3 Hz, 1H), 7.67-7.73 (m, 4H), 8.13 (d-like, J ) 7.3
Hz, 2H); 13C NMR (100.6 MHz, CDCl3) δ (ppm) 21.75 (q), 22.48
(q), 76.80 (s), 126.4 (s), 128.2 (d), 129.1 (d), 129.3 (d), 129.9
(d), 130.3 (d), 130.8 (d), 132.6 (s), 132.8 (d), 136.7 (s), 138.6
colorless crystals; mp 96 °C; 1H NMR (400 MHz, CDCl3) δ
(ppm) 2.43 (s, 3H), 2.80-2.94 (m, 2H), 5.12 (dd, J ) 10.6, 4.0
Hz, 1H), 5.66 (dt, J ) 15.1, 7.4 Hz, 1H), 6.45 (dt, J ) 15.1, 1.2
Hz, 1H), 7.13-7.25 (m, 5H), 7.30 (d, J ) 8.1 Hz, 2H), 7.48 (t-
like, J ) 7.7 Hz, 2H), 7.60-7.64 (m, 3H), 7.94 (d-like, J ) 7.3
Hz, 2H); 13C NMR (100.6 MHz, CDCl3) δ (ppm) 21.80 (q), 33.02
(t), 68.99 (d), 123.1 (d), 127.4 (d), 128.9 (d), 129.2 (d), 129.3
(d), 129.7 (d), 129.7 (d), 129.9 (d), 132.4 (d), 133.2 (s), 134.2
(d), 137.1 (s), 145.7 (s), 191.9 (s); IR (KBr) 1678, 1597, 1320,
1145 cm-1; MS (EI) m/z 470; exact mass M+ 470.0484 (calcd
for C24H22O3SSe 470.0455).
(d), 145.3 (s), 194.4 (s); IR (neat) 1669, 1597, 1319, 1149 cm-1
;
MS (EI) m/z 444; exact mass M+ 444.0293 (calcd for C22H20O3-
SSe 444.0299).
Rea ction of 1 a n d 11 in th e P r esen ce of Zn I2. To a
solution of 1 (222 mg, 0.87 mmol) in dichloromethane (1.7 mL)
was added ZnI2 (417 mg, 1.31 mmol), followed by a solution of
1-phenyl-2-(p-toluenesulfonyl)-2-propen-1-one (11) (239 mg,
0.87 mmol) in dichloromethane (0.35 mL) at -78 °C. The
mixture was allowed to warm to -30 °C and stirred for 5.5 h.
The reaction mixture was quenched by triethylamine (0.28 mL,
203 mg, 2.0 mmol) and then saturated aqueous NaHCO3. The
mixture was extracted with dichloromethane, and the organic
phase was washed with water, dried (Na2SO4), and evaporated
in vacuo. The residue was purified by column chromatography
over silica gel eluting with hexane-CH2Cl2 to give recovered
1 (140 mg, 63%) and 12 (47 mg, 12%) (Rf ) 0.5 CH2Cl2). 12:
Ack n ow led gm en t. We are grateful to Dr. K. Yama-
moto (Osaka University) for measurement of mass
spectra and elemental analysis.
Su p p or tin g In for m a tion Ava ila ble: Experimental de-
tails of X-ray structure determination for 4a and additional
results of ab initio calculations. This material is available free
of charge via the Internet at http://pubs.acs.org.
J O9911591