Chemistry of Conversions of [o-[1-Halo-1-(p-tolylsulfonyl)alkyl]benzyl]trimethylsilanes to o-Quinodimethanes and Benzocyclobutenes

Article abstract of DOI:10.1021/jo9705935

Trimethyl[o-[bromo(p-tolylsulfonyl)methyl]benzyl]silane (10) is prepared from o-[(trimethylsilyl)-methyl]benzyl p-tolyl sulfone (9), n-BuLi, and bromine. Sulfone 9 eliminates trimethylsilyl bromide upon reaction with TBAF in acetonitrile to give the presumed intermediate, α-sulfonyl-o-quinodimethane 11, which (1) dimerizes to disulfone 12 and (2) is trapped by alkyl fumarates to yield (p-tolylsulfonyl)tetrahydronaphthalenes 17a,b and 18a,b, respectively. Sulfone 9 is converted by n-BuLi and alkyl halides to α-alkyl-α-bromosulfones 19a-f which react with TBAF to give α-sulfonylbenzocyclobutenes 21a-f and vinyl sulfones 23a-f, apparently upon ring closure and upon 1,5-sigmatropic rearrangements of hydrogen in α-sulfonyl-o-quinodimethane intermediates 20a-f and 22a-f. Further, sulfone 9, n-BuLi, and tert-butyl hypochlorite yield α-chlorosulfone 26 and α,α-dichlorosulfone 27. TBAF effects dechlorotrimethylsilation of 27 to chloro(p-tolylsulfonyl)cyclobutene 28 presumably upon formation and cyclization of o-quinodimethane 29. Silanes 10, 19a-f, and 27 are therefore practical synthons for o-quinodimethane intermediates 11, 20a-f and 22a-f, and 29 respectively.

Full text of DOI:10.1021/jo9705935

2086
J . Org. Chem. 1998, 63, 2086-2093
Ch em istr y of Con ver sion s of
[o-[1-Ha lo-1-(p-tolylsu lfon yl)a lk yl]ben zyl]tr im eth ylsila n es to
o-Qu in od im eth a n es a n d Ben zocyclobu ten es
Brian D. Lenihan and Harold Shechter*
Department of Chemistry, The Ohio State University, Columbus, Ohio 43210
Received April 1, 1997 (Revised Manuscript Received October 14, 1997)
Trimethyl[o-[bromo(p-tolylsulfonyl)methyl]benzyl]silane (10) is prepared from o-[(trimethylsilyl)-
methyl]benzyl p-tolyl sulfone (9), n-BuLi, and bromine. Sulfone 9 eliminates trimethylsilyl bromide
upon reaction with TBAF in acetonitrile to give the presumed intermediate, R-sulfonyl-o-
quinodimethane 11, which (1) dimerizes to disulfone 12 and (2) is trapped by alkyl fumarates to
yield (p-tolylsulfonyl)tetrahydronaphthalenes 17a ,b and 18a ,b, respectively. Sulfone 9 is converted
by n-BuLi and alkyl halides to R-alkyl-R-bromosulfones 19a -f which react with TBAF to give
R-sulfonylbenzocyclobutenes 21a -f and vinyl sulfones 23a -f, apparently upon ring closure and
upon 1,5-sigmatropic rearrangements of hydrogen in R-sulfonyl-o-quinodimethane intermediates
20a -f and 22a -f. Further, sulfone 9, n-BuLi, and tert-butyl hypochlorite yield R-chlorosulfone
26 and R,R-dichlorosulfone 27. TBAF effects dechlorotrimethylsilation of 27 to chloro(p-tolylsul-
fonyl)cyclobutene 28 presumably upon formation and cyclization of o-quinodimethane 29. Silanes
10, 19a -f, and 27 are therefore practical synthons for o-quinodimethane intermediates 11, 20a -f
and 22a -f, and 29 respectively.
In tr od u ction
R,R-Dialkyl-o-[(trimethylsilyl)methyl]benzyl p-tolyl sul-
fones (1) are eliminated by fluoride ion to R,R-dialkyl-o-
quinodimethanes (2).1 Such o-quinodimethanes (2) are
of interest with respect to their multiplicities, ring
closures to R,R-dialkylbenzocyclobutenes (3, eq 1), and
Diels-Alder reactions with electron-deficient olefins (4,
eq 2).1 Of further significance is that 5, with Z-R-alkyl
groups with â-hydrogen, undergoes 1,5-sigmatropic rear-
rangements of hydrogen to give styrene derivatives 6 (eq
3). Study of synthesis and the behaviors of R-halo and
R,R-dihalosilyl sulfones 7 and 8 with fluoride ion and the
chemistry of the products thereof are now reported.2 The
uses of these reactions for advantageous synthesis have
been emphasized in the present work.
Resu lts a n d Discu ssion
n-BuLi (1 equiv) and then bromine (2 equiv) to give
R-bromosulfone 10 (eq 4) in 65% yield. Use of less than
2 equiv of bromine results in recovery of large proportions
Syn th esis a n d Rea ction s of Tr im eth yl[o-[br om o-
(p-tolylsu lfon yl)m eth yl]ben zyl]sila n e (10). o-[(Tri-
methylsilyl)methyl]benzyl p-tolyl sulfone (9) reacts with
(1) (a) Lenihan, B. D.; Shechter, H. Tetrahedron Lett. 1994, 35, 7505.
(b) Lenihan, B. D.; Shechter, H. J . Org. Chem. 1998, 63, 2072.
(2) Dechlorotrimethylsilylation of R-chlorosulfones is reported to be
useful for synthesis of vinyl sulfones: (a) Hsiao, C.-N.; Shechter, H. J .
Org. Chem. 1988, 53, 2688. (b) Hsiao, C. N.; Shechter, H. Tetrahedron
Lett. 1982, 23, 3455.
S0022-3263(97)00593-8 CCC: $15.00 © 1998 American Chemical Society
Published on Web 03/17/1998

[o-[Halo(p-tolylsulfonyl)alkyl]benzyl]trimethylsilane Conversion
J . Org. Chem., Vol. 63, No. 7, 1998 2087
Ta ble 1. Cou p lin g Con sta n tsa for
Tetr a h yd r on a p h th a len es 17a ,b a n d 18a ,b
of the initial 9. Reaction of 10 with TBAF in acetonitrile
induces 1,4-elimination of trimethylsilyl bromide to give
R-sulfonyl-o-quinodimethane 11 (eq 5) which dimerizes
in situ to a disulfone assigned as 12. Dimerization of 11
compd
J cd
J de
enhancement at Hd
17a
17b
18a
18b
12.7
10.6
13a
4.3
4.3
4a
18.0%
7.3%
18.8%
6.4%
10.6
4.2
a
The coupling constants could not be determined accurately to
the next decimal place in this experiment.
Ta ble 2. Syn th esis of r-Alk yl-r-br om osu lfon es 19a ,b
fr om Su lfon e 9
product
R
yield, %
19a
19b
19c
19d
19e
19f
methyl
ethyl
butyl
benzyl
4-pentenyl
2-propyl
70
52
72
60
58
66
(R ) Me) and 18b (R ) Et) are obtained in 30-31% yields
by chromatography of the acetone mother liquors on silica
gel. Reactions of 17a with the fumarates using cesium
fluoride instead of TBAF are slow (7-9 days), but the
systems are cleaner and isomers 17b and 18b are easier
to purify. Under conditions successful with the above
fumarates, neither diethyl maleate nor acrylonitrile adds
to 11.
via Diels-Alder reactions might also be expected to give
1
13, 14, and/or 15. The H NMR of the product reveals
absorption, however, for only one aliphatic (sp3-s) proton
(δ 4-5) R to a sulfone group, and the signal for that
proton is a sharp singlet. Structures 14 and 15 are ruled
out for the dimer because they each have two aliphatic
protons R to sulfone groups. Further, because the signal
for the sp3-s proton is a singlet, the proton is not on a
carbon attached to carbon-containing hydrogen. The
observations exclude the head to tail product 13. The
1H NMR therefore indicates that the dimer is the head
to head product assigned as 12 (eq 5). Of interest is that
12 is the product predicted on the basis of stepwise
dimerization of 11 as a diradical to give highly stabilized
diradical 16.
The configurations of 17a -18b are assigned by NMR
methods. The Hd-He coupling constants for 17a -18b
are similar and thus are not usable to establish configu-
rations. NOE irradiation of the R-sulfonyl protons He in
17a and 17b (Table 2) do allow assignments. Isomer 17a
gives a much larger enhancement at Hd (18.0%) than does
17b (7.3%). These data support cis stereochemistry for
HdHe in 17a and trans stereochemistry for HdHe in 17b.
Such NOE results are also obtained for 18a and 18b
(Table 1). The coupling constants between Hc and Hd are
large for 17a ,b and 18a ,b (Table 1) and support the trans
stereochemistries as expected for cycloadditions of 11 to
fumarate esters.
Syn th esis of r-Alk yl-r-br om osu lfon es 19a -f a n d
Th eir Con ver sion s to Ben zocyclobu ten es 21a ,b.
R-Alkyl-R-bromosulfones 19a -f are readily prepared (eq
6) from sulfone 9 by addition of n-BuLi and then a halide
followed by n-BuLi and then bromine (Table 2). R-Bromo-
R-methylsulfone 19a could not be prepared efficiently in
one pot because in the initial methylation methyl iodide
was used and lithium iodide was formed. Unless the
lithium iodide is removed, subsequent reactions of the
product mixture with n-BuLi and bromine are compli-
cated by oxidation of iodide ion to iodine. R-Alkyl-R-
bromosulfones 19b-19e are obtained satisfactorily, how-
ever, in single-pot procedures from the corresponding
primary bromides (RX ) RpBr, eq 6). Alkylation of 9
upon reactions with n-BuLi and 2-bromopropane is
complicated by elimination of the secondary bromide.
Generation of o-quinodimethane 11 from 10 in the
presence of dimethyl fumarate and diethyl fumarate
gives (p-tolylsulfonyl)tetrahydronaphthalenes 17a ,b and
18a ,b, respectively, in 71-93% yields. Isomers 17a (R
) Me) and 18a (R ) Et) are isolated pure in 31-38%
yields upon crystallization from acetone. Isomers 17b

2088 J . Org. Chem., Vol. 63, No. 7, 1998
Lenihan and Shechter
Ta ble 3. Syn th esis of Ben zocyclobu ten es 21a -f a n d Vin yl Su lfon es 23a -f fr om r-Alk yl-r-br om osu lfon es 19a -f
Multiple additions of n-BuLi and 2-bromopropane are
required, and the initial monoalkylated sulfone is best
isolated pure before effecting its conversions by n-BuLi
and then bromine to 19f.
23a -f (eq 8) as summarized in Table 3.3,4 Other than
for 21a , benzocyclobutenes 21b-f are the major products
(49-61% yields); vinyl sulfones 23b-f are formed in 15-
(3) For reviews of benzocyclobutenes and quinodimethanes, see ref
1 and its extensive references.
(4) 4,6-Dimethylbenzocyclobutenyl p-tolyl sulfone has been prepared
by pyrolysis of the sodium salt of 4,6-dimethylbenzocyclobutenone
(p-toluenesulfonyl)hydrazone: (a) Blomquist, A. T.; Heins, C. F. J . Org.
Chem. 1969, 34, 2906. R-Sulfonylbenzocyclobutenes can also be
synthesized by ring closures involving benzyne intermediates: (b)
Bunnett, J . F.; Skorcz, J . A. J . Org. Chem. 1962, 27, 3836. (c) Gowland,
B. D.; Durst, T. Can. J . Chem. 1979, 57, 1462. (d) Iwao, M. J . Org.
Chem. 1990, 55, 3622. Ring closure through benzyne intermediates is
a general method for synthesis of 1-substituted benzocyclobutenes: (e)
Skorcz, J . A.; Kaminski, F. E.; Williams, V. Z.; Wiberg, K. B. Org.
Synth. Collect. Vol. V, 1973, 263. (f) Macdonald, D. I.; Durst, T.
Tetrahedron Lett. 1986, 27, 2235. (g) Macdonald, D. I.; Durst, T. J .
Org. Chem. 1988, 53, 3663.
Of particular interest is that R-alkyl-R-bromosulfones
19a -f are converted by TBAF in acetonitrile at 20-25
°C to benzocyclobutenes 21a -f (eq 7) and vinyl sulfones

[o-[Halo(p-tolylsulfonyl)alkyl]benzyl]trimethylsilane Conversion
J . Org. Chem., Vol. 63, No. 7, 1998 2089
22% yields. The benzocyclobutenes give acceptable analy-
ses and expected MS data. The most definitive evidence
that 21a -f are benzocyclobutenes are the 1H NMR
spectra of the cyclobutene ring hydrogens as doublets of
doublets at δ 3-4 with the exception of the absorption
for 21f. The nonequivalent cyclobutene hydrogens in
21a -e have geminal coupling constants of ∼14-15 Hz.
The cyclobutene ring protons of 21f appear as an NMR
singlet because by coincidence the hydrogens all have the
same chemical shifts. The vinyl sulfones 23a -f are
Syn th esis a n d Con ver sion of [o-[Dich lor o(p-tolyl-
su lfon yl)m et h yl]b en zyl]t r im et h ylsila n e (27) t o
r-Ch lor o-r-(p-tolylsu lfon yl)ben zocyclobu ten e (28).
Sulfone 9 reacts with n-BuLi in hexane and then tert-
butyl hypochlorite (4 equiv) to give R-chlorosulfone 26
(11%) and R,R-dichlorosulfone 27 (41%). R,R-Dichloro-
sulfone 27 undergoes fluoride-induced dechlorotrimeth-
ylsilylation in acetonitrile at 0 °C to yield R-chloro-R-(p-
tolylsulfonyl)benzocyclobutene (28, 51%). The structure
of 28 is assigned from its analyses, its MS patterns, and
its 1H NMR doublets at δ 3.62 and 4.20. o-Quin-
odimethane 29 may be a reaction intermediate in elimi-
nation of 27 although it could not be trapped by dimethyl
fumarate or ethyl vinyl ether.
1
assigned from their analyses and/or HRMS and their H
NMR absorptions for vinyl hydrogens.
The reactions of 19a -f with fluoride ion may be
envisaged (eqs 7 and 8) to involve 1,4-eliminations to give
isomeric o-quinodimethanes 20a -f and 22a -f which,
depending on their stereochemistries, undergo intramo-
lecular 2 + 2 cycloadditions yielding benzocyclobutenes
21a -f or 1,5-sigmatropic rearrangements of hydrogen to
form vinyl sulfones 23a -f. Alternate mechanisms for
formation of 21a -f and 23a -f which bypass o-quin-
odimethane intermediates involve eliminations with
concerted ring closures to 21a -f and eliminations with
concerted hydrogen transfers to yield 23a -f. What can
be added to these questions of reaction mechanism are
that efforts to generate and trap 20a -f and 22a -f with
fumarate esters have failed and that elimination of
R-bromo-R-(4-pentenyl)sulfone 19e with TBAF gives ben-
zocyclobutene 21e and vinyl sulfone 23e (eqs 7 and 8,
Table 3) but none of the intramolecular capture product
25 (eq 9). On the basis that o-quinodimethane 11 is
indeed formed from 10 (eq 5) and the intimate details of
elimination of 19a -f have not been established, steric
effects are clearly important in the conversions to 21a -f
and 23a -f and, as will be explained, the overall results
are readily understandable on the basis of generation and
subsequent reactions of o-quinodimethane intermediates
20a -f and 22a -f (eqs 7 and 8). Thus in elimination of
19a , quinodimethane 22a is formed (eqs 7 and 8) in
preference to 20a because the steric effect of the methyl
group is less than that of the p-tolylsulfonyl group and
then 1,5-sigmatropic rearrangement of one of the three
hydrogen atoms of the methyl group in 22a yields 23a
as the major product. In 19b-f the R-alkyl groups are
bulkier than methyl and then formation of o-quin-
odimethanes 20b-f is more predominant than for 22b-
f. A further point is that the number of hydrogens in
the 6-positions for sigmatropic rearrangement are less
in 20b-f than in 20a . On the basis of steric and
statistical factors, o-quinodimethanes 20b-f form and
then ring close more readily than does 20a .
Con clu sion s
Halo(p-tolylsulfonyl)trimethylsilanes 10, 19a -f, and
27 undergo efficient dehalotrimethylsilations upon reac-
tions with TBAF in acetonitrile at 0-25 °C to give the
presumed intermediates, R-sulfonyl-o-quinodimethanes
11, 20a-f, 22a-f, and 29, respectively. o-Quinodimethane
11 undergoes directed 2 + 4 dimerization to disulfone
12 and is intercepted by dimethyl fumarate and diethyl
fumarate to yield (p-tolylsulfonyl)tetrahydronaphthalenes
17a ,b and 18a ,b, respectively. Of note is that the
R-alkyl-R-bromosulfones 19a -f react with TBAF to give
stable benzocyclobutenes 21a -f and vinyl sulfones 23a -
f. Cyclobutenes 21a -f are presumably formed by ring
closures of 20a -f and 22a -f. Vinyl sulfones 23a -f are
apparently produced by 1,5-sigmatropic rearrangements
of hydrogen in 22a -f. Conversion of 27 by TBAF via
quinodimethane 29 to R-chloro-R-sulfonylbenzocyclobutene
(28) is an elegant preparative reaction, and various
transformations of 28 are being studied.
Exp er im en ta l Section
Gen er a l Meth od s. The analytical, chromatographic, and
spectral procedures used are identical with those previously
described.1b
Gen er a l P r oced u r e for r-Br om in a t ion of Su lfon es.
[o-[Br om o(p -t olylsu lfon yl)m e t h yl]b e n zyl]t r im e t h yl-
sila n e (10). To trimethyl[o-[(p-tolylsulfonyl)methyl]benzyl]-
silane (9, 10.00 g, 30.1 mmol) in anhydrous THF (150 mL) at

2090 J . Org. Chem., Vol. 63, No. 7, 1998
Lenihan and Shechter
-78 °C was added n-BuLi (23.4 mL, 31.6 mmol, 1.35 M in
hexane). The yellow mixture was warmed to room tempera-
ture and then cooled to -78 °C. Bromine (3.1 mL, 60.1 mmol)
was added in a single portion, and the mixture was then
warmed to room temperature. After having been diluted with
1 M NaHSO3, the mixture was extracted with diethyl ether.
The aqueous layer was again extracted with diethyl ether, and
the combined extracts were dried over MgSO4 and concen-
trated. The resulting product was crystallized twice from
methanol to yield 10 as a white crystalline solid (8.03 g, 65%,
Impure fractions (136 mg) from the chromatography were
judged by NMR to be 25% 17a and 75% 17b, which corre-
sponds to additional yields of 6% and 20%, respectively.
P r ep a r a tion of Dieth yl 1,2,3,4-Tetr a h yd r o-1-(p-tolyl-
su lfon yl)-2,3-n a p h th a len ed ica r boxyla tes (18a ,b) Usin g
Cesiu m F lu or id e. A suspension of cesium fluoride (0.37 g),
10 (500 mg, 1.22 mmol), diethyl fumarate (800 mL, 4.88 mmol),
and acetonitrile (8 mL) was stirred for 9 days. The reaction
mixture was worked up as for 17a ,b. After the diethyl
fumarate had been removed, recrystallization of the residue
from acetone gave 18a (195 mg, 37%; mp 206-208 °C): IR
mp 98.5-101 °C): IR (KBr) 1596, 1319, 1250, 1150, 850 cm-1
;
1
(KBr) 1730, 1325, 1175, 1150 cm-1; H NMR (CDCl3) δ 1.31
1H NMR (CDCl3) δ -0.01 (9H, s), 1.80 (1H, d, J ) 14.4 Hz),
2.00 (1H, d, J ) 14.4 Hz), 2.42 (3H, s), 5.95 (1H, s), 6.83-7.63
(8H, m); 13C NMR (CDCl3) δ -1.5 (q), 21.7 (q), 23.9 (t), 62.6
(d), 124.8 (d), 127.9 (s), 129.3 (d), 129.4 (d), 129.8 (d), 130.2
(d), 131.4 (d), 132.0 (s), 140.2 (s), 145.6 (s); MS(EI) m/e (relative
intensity) 412.03 (1), 410.04 (1), 257.02 (49), 255.02 (48), 103.06
(49), 73.05 (100); HRMS calcd for C18H23BrO2SSi 410.0372;
found 410.0373. Anal. Calcd for C18H23BrO2SSi: C, 52.55; H,
5.63. Found: C, 52.77; H, 5.46.
(3H, t, J ) 7.1 Hz), 1.36 (3H, t, J ) 7.1 Hz), 2.44 (3H, s), 2.76-
2.87 (1H, dd, J ) 8.7, 17.7 Hz), 3.34 (1H, dd, J ) 9.1, 17.8
Hz), 3.42 (1H, dd, J ) 4, 13 Hz), 3.75 (1H, dt, J ) 9, 13 Hz),
4.17-4.93 (4H, two superimposed q, J ) 7.1 Hz), 4.93 (1H, d,
J ) 4.1 Hz), 6.67-7.45 (8H, m); 13C NMR (CDCl3) δ 14.0 (q),
14.1 (q), 21.6 (q), 30.8 (s), 31.0 (t), 36.4 (d), 43.3 (d), 60.9 (t),
61.4 (t), 67.2 (d), 125.5 (d), 127.7 (s), 128.9 (d), 129.3 (d), 129.4
(d), 130.4 (d), 135.2 (s), 136.2 (s), 145.0 (s), 170.3 (s), 175.0 (s);
NOE differences with irradiation at δ 4.92 give enhancements
at δ 3.42 (dd, 18.8%), δ 6.65-6.75 (15.0%), and δ 7.4-7.5
(6.1%); MS(EI) m/e (relative intensity) 275.13 (14), 229.09 (44),
201.09 (73), 129.08 (94). Anal. Calcd for C23H26O6S: C, 64.17;
H, 6.09. Found: C, 64.39; H, 6.13.
P r ep a r a tion of 3′,4′-Dih yd r o-1′-(p-tolylsu lfon yl)-6-[(p-
t olylsu lfon yl)m et h ylen e]sp ir o[2,4-cycloh exa d ien e-1,2′-
(1′H)-n a p h th a len e] (12). To 10 (0.500 g, 1.22 mmol) in
acetonitrile (8 mL) was added TBAF (2.5 mL, 2.5 mmol, 1.0
M in acetonitrile) over 40 min. The mixture was diluted with
CH2Cl2, washed with water, dried over MgSO4, and concen-
trated. The residue was crystallized from 1:1 acetone:chloro-
form to yield 12 as a pale yellow solid (85 mg, 27%, mp 208-
The mother liquor on concentration and chromatography on
silica gel gave 18b (157 mg, 30%), an oil: IR (KBr) 1732, 1317,
1213, 1146, 757, 578 cm-1 1H NMR (CDCl3) δ 1.19 (3H, t),
;
1.29 (3H, t), 2.41 (3H, s), 2.51 (1H, d), 2.59-2.73 (2H, m), 3.97
(1H, dd, J ) 4.2, 10.6 Hz), 4.05-4.3 (4H, m), 5.04 (1H, d, J )
4.1 Hz), 7.06 (1H, d), 7.1-7.3 (5H, m), 7.4-7.5 (2H, m); NOE
differences with irradiation at δ 5.04 gave enhancements at δ
2.6-2.75 (1.2%), δ 3.97 (6.4%), δ 7.2-7.3 (13.3%), and δ 7.4-
7.5 (4.6%). Impure fractions yielded 170 mg of a mixture of
18a and 18b in a ratio of 15:85, respectively, as judged by
NMR. The additional yields of 18a and 18b are 6% and 26%,
respectively.
209 °C): IR (neat) 1596, 1301, 1144, 1086 cm-1 1H NMR
;
(CDCl3) δ 1.72-1.79 (1H, m), 2.38 (3H, s), 2.40 (3H, s), 2.83-
3.03 (2H, m), 3.08-3.17 (1H, m), 4.26 (1H, d, J ) 1.3 Hz), 5.70
(1H, dd, J ) 0.6, 9.5 Hz), 5.87 (1H, dd, J ) 5.1, 9.5 Hz), 6.17
(1H, ddt, J ) 5.2, 9.9, 1.4 Hz), 6.41 (1H, t, J ) 1.3 Hz), 6.45
(1H, d, J ) 7.6 Hz), 6.76-6.82 (1H, m), 7.07-7.20 (6H, m),
7.31 (2H, m), 7.48 (1H, d), 7.91-7.95 (2H, m); MS(EI) m/e
(relative intensity) 361.12 (9), 206.11 (49), 205.10 (100), 191.09
(18), 139.03 (13), 91.06 (28).
P r ep a r a tion of Dim eth yl 1,2,3,4-Tetr a h yd r o-1-(p-tolyl-
su lfon yl)-2,3-n a p h th a len ed ica r boxyla tes (17a ,b) Usin g
TBAF . A solution of 10 (250 mg, 0.61 mmol) and dimethyl
fumarate (350 mg, 2.43 mmol) in CH2Cl2 (4 mL) at 0 °C was
treated with TBAF (1.2 mL, 1.2 mmol, 1.0 M in acetonitrile)
over 30 min. After product workup, the dimethyl fumarate
was removed via sublimation and the residue was recrystal-
lized from acetone to yield 17a (77 mg, 31%). The 1H NMR
agreed with that of 17a described previously. Chromatogra-
phy of the mother liquor on silica gel using CHCl3 yielded an
impure mixture (117 mg) which NMR indicated to be 19% 17a
and 65% 17b, which corresponds to yields of 9% and 31%,
respectively.
P r ep a r a tion of Dim eth yl 1,2,3,4-Tetr a h yd r o-1-(p-tolyl-
su lfon yl)-2,3-n a p h th a len ed ica r boxyla tes (17a ,b) Usin g
Cesiu m F lu or id e. A mixture of cesium fluoride (0.37 g), 10
(500 mg, 1.22 mmol), dimethyl fumarate (700 mg, 4.88 mmol),
and acetonitrile (8 mL) was stirred for 7 days under argon.
The mixture was diluted with water and extracted with CH2-
Cl2. The organic layer was washed with water, dried over
MgSO4, and concentrated to a white solid. The dimethyl
fumarate was removed by vacuum sublimation, and the
residue was recrystallized from acetone to yield 17a (184 mg,
38%; mp 228-231 °C dec): IR (neat) 1732, 1317, 1170, 1142
1
cm-1; H NMR (CDCl3) δ 2.43 (3H, s), 2.81 (1H, dd, J ) 8.8,
17.7 Hz), 3.29 (1H, dd, J ) 8.8, 17.7 Hz), 3.43 (1H, dd, J )
4.3, 12.7 Hz), 3.68-3.80 (7H, two s and superimposed m), 4.93
(1H, d, J ) 4.3 Hz), 6.72-7.43 (8H, m); 13C NMR (CDCl3) δ
21.7 (q), 31.0 (t), 36.3 (d), 43.2 (d), 52.3 (q), 52.6 (q), 67.2 (d),
125.7 (d), 127.5 (s), 129.0 (d), 129.4 (d), 129.5 (d), 130.6 (d),
135.2 (s), 136.2 (s), 145.1 (s), 170.9 (s), 175.7 (s); NOE
differences with irradiation at δ 4.94 give enhancements at δ
3.43 (dd, 18.0%), δ 6.7-6.8 (14.5%), and δ 7.35-7.5 (5.7%);
MS(EI) m/e (relative intensity) 247.10 (12), 215.07 (30), 187.08
(70), 128.07 (43). Anal. Calcd for C21H22O6S: C, 62.67; H, 5.51.
Found: C, 62.44; H, 5.56.
P r ep a r a tion of Dieth yl 1,2,3,4-Tetr a h yd r o-1-(p-tolyl-
su lfon yl)-2,3-n a p h th a len ed ica r boxyla tes (18a ,b) Usin g
TBAF . TBAF (2.5 mL, 2.5 mmol, 1.0 M in acetonitrile) in
acetonitrile (5 mL) was added in 100 min to 10 (506 mg, 1.23
mmol) and diethyl fumarate (1.00 mL, 6.10 mmol) in anhy-
drous acetonitrile (5 mL) at 0 °C. The white cloudy mixture
was worked up as for 17a ,b. The residue was recrystallized
from acetone to yield 18a (203 mg, 38%) for which the 1H NMR
agreed with that of 18a described previously. Chromatogra-
phy of the mother liquor on silica gel using 1:19 ethyl acetate:
1
ligroin gave 18b (118 g, 22%) which has an H NMR spectrum
Concentration and chromatography of the mother liquor
using silica gel and CHCl3 yielded 17b as a white solid (118
mg, 24%, mp 140-146 °C): IR (neat) 1740, 1436, 1316, 1219,
1144 cm-1; 1H NMR (CDCl3) δ 2.40 (3H, s), 2.52 (1H, d), 2.64-
2.75 (2H, m), 3.66 (3H, s), 3.74 (3H, s), 3.96 (1H, dd, J ) 4.3,
10.6 Hz), 5.01 (1H, d, J ) 4.3 Hz), 7.05 (1H, d), 7.15-7.28 (5H,
m), 7.41-7.45 (2H, m); 13C NMR (CDCl3) δ 21.6, 31.9, 42.6,
43.8, 52.3, 52.8, 66.9, 126.3, 126.7, 128.0, 128.9, 129.4, 129.7,
131.7, 133.1, 138.3, 145.0, 172.5, 173.4; NOE differences with
irradiation at δ 5.0 give enhancements at δ 2.6-2.8 (2.1%), δ
3.96 (dd, 7.2%), δ 7.15-7.25 (12.7%), and δ 7.4-7.5 (5.1%);
MS(EI) m/e (relative intensity) 247.10 (6), 215.07 (27), 187.08
(100), 128.06 (83). Anal. Calcd for C21H22O6S: C, 62.67; H,
5.51. Found: C, 62.74; H, 5.48.
similar to that previously described.
[o-[1-Br om o-1-(p -t olylsu lfon yl)et h yl]b en zyl]t r im et h -
ylsila n e (19a ). The product of reaction of trimethyl[o-[1-(p-
tolylsulfonyl)ethyl]benzyl]silane1b (6.50 g, 18.8 mmol) with
n-BuLi (13.2 mL, 19.7 mmol, 1.49 M in hexane) and then
bromine (1.9 mL, 38 mmol) is an oil which was crystallized
twice from methanol to yield 19a as a white solid (5.57 g,
70%): IR (KBr) 1593, 1322, 1303, 1248, 1153, 848 cm-1; H
1
NMR (CDCl3) δ 0.05 (9H, s), 2.33-2.39 (4H, s and superim-
posed d), 2.52 (3H, s), 3.12 (1H, d, J ) 14.4 Hz), 6.86-7.45
(8H, m); 13C NMR (CDCl3) δ -0.5, 21.6, 26.9, 31.6, 79.2, 123.6,
129.0, 129.4, 130.6, 130.8, 131.0, 131.9, 144.5, 145.1; MS(EI)
m/e (relative intensity) 218.99 (35), 191.12 (31), 131.00 (38),
117.07 (49), 91.06 (37), 73.05 (100). Two crystallizations from

[o-[Halo(p-tolylsulfonyl)alkyl]benzyl]trimethylsilane Conversion
J . Org. Chem., Vol. 63, No. 7, 1998 2091
methanol yielded an analytical sample (mp 106 °C). Anal.
Calcd for C19H25BrO2SSi: C, 53.64; H, 5.92. Found: C, 53.42;
H, 5.89.
(d), 130.9 (s), 131.3 (d), 131.5 (d), 132.2 (d), 137.5 (d), 145.1
(s), 145.5 (s); MS(EI) m/e (relative intensity) 229.07 (16), 171.12
(27), 129.07 (48), 91.06 (26), 73.05 (100). A portion of the solid
was recrystallized from petroleum ether to obtain an analytical
sample (mp 112-114 °C). Anal. Calcd for C23H31BrO2SSi: C,
57.61; H, 6.52. Found: C, 57.46; H, 6.55.
[o-[1-B r o m o -1-(p -t o ly ls u lfo n y l)p r o p y l]b e n zy l]t r i-
m eth ylsila n e (19b). Alkylation of 9 (2.00 g, 6.01 mmol) with
n-BuLi (2.30 mL, 6.2 mmol, 2.71 M in hexane) and ethyl
bromide (0.47 mL, 6.32 mmol) followed by n-BuLi (2.30 mL,
6.2 mmol, 2.71 M in hexane) and bromine (0.62 mL, 12.0 mmol)
and workup gave an oil which crystallized from methanol to
yield 19b (1.36 g, 52%, mp 92-97 °C): IR (KBr) 1594, 1319,
[o-[1-Br om o-2-m eth yl-1-(p-tolylsu lfon yl)pr opyl]ben zyl]-
tr im eth ylsila n e (19f). Reaction of trimethyl[o-[2-methyl-1-
(p-tolylsulfonyl)propyl]benzyl]silane1b (1.00 g, 2.67 mmol) with
n-BuLi (1.15 mL, 2.80 mmol, 2.44 M in hexane) and bromine
(0.27 mL, 5.3 mmol) and workup gave an oil which after
chromatography on silica gel using 1:19 ethyl acetate:ligroin
yielded 19f, an oil, as the first eluent (1.09 g). Crystallization
from petroleum ether gave pure 19f (mp 89-93 °C, 0.801 g,
1
1304, 1247, 1147, 846 cm-1; H NMR (CDCl3) δ 0.02 (9H, s),
1.11 (3H, t, J ) 7.0 Hz), 2.01 (1H, d, J ) 14.2 Hz), 2.39 (3H,
s), 2.42-2.63 (1H, m), 2.84-3.02 (1H, m), 3.21 (1H, d, J ) 14.2
Hz), 6.84-6.99 (2H, m), 7.05-7.40 (4H, m), 7.3-7.4 (2H, br
d); 13C NMR (CDCl3) δ -0.6, 10.0, 21.6, 26.5, 32.6, 87.5, 123.4,
127.0, 128.9, 129.2, 130.9, 131.3, 131.4, 132.2, 145.0, 145.7;
MS(EI) m/e (relative intensity) 285.05 (35), 283.05 (32), 229.07
(24), 131.09 (39), 91.07 (51), 73.05 (100). Recrystallization from
ligroin yielded an analytical sample of 19b (mp 97-98.5 °C).
Anal. Calcd for C20H27BrO2SSi: C, 54.66; H, 6.19. Found: C,
54.76; H, 6.22.
66%): IR (KBr) 1597, 1316, 1247, 1156, 854 cm-1 1H NMR
;
(CDCl3) δ 0.01 (9H, s), 0.95 (3H, d, J ) 6.5 Hz), 1.57 (3H, d, J
) 6.1 Hz), 2.34 (3H, s), 2.83 (1H, d, J ) 14.4 Hz), 3.45-3.5
1
(1H, m), 6.8-7.2 (7H, m), 7.48-7.53 (1H, m); H NMR (C6D6,
350 K) δ 0.04 (9H, s), 0.88 (3H, d, J ) 6.5 Hz), 1.69 (3H, d, J
) 6.1 Hz), 1.87 (3H, s), 2.03 (1H, d, J ) 14.4 Hz), 3.05 (1H, d,
J ) 14.5 Hz), 3.55 (1H, septet, J ) 6.3 Hz), 6.62-6.72 (3H,
m), 6.83-6.93 (2H, m), 7.36 (2H, d), 7.56-7.60 (1H, d); 13C
NMR (CDCl3) δ -0.4 (q), 20.5 (q), 21.1 (q), 21.5 (q), 26.2 (t),
35.5 (d), 123.7 (d), 128.5 (d), 128.7 (d), 130.9 (d), 132.4 (d), 132.8
(s), 144.6 (s); 13C NMR (C6D6, 350 K) δ -0.2, 21.0, 21.1, 21.5,
26.9, 36.1, 98.5, 124.1, 128.6, 128.7, 131.5, 132.5, 132.7, 133.9,
134.7, 144.0, 144.3; MS(EI) m/e (relative intensity) 145.09 (33),
91.05 (16), 73.04 (100). Recrystallization from ligroin yielded
an analytical sample of 19f. Anal. Calcd for C21H29BrO2SSi:
C, 55.62; H, 6.45. Found: C, 55.79; H, 6.42.
[o-[1-B r o m o -1-(p -t o ly ls u lfo n y l)p e n t y l]b e n zy l]t r i-
m eth ylsila n e (19c). Alkylation of 9 (2.00 g, 6.01 mmol) using
n-BuLi (2.30 mL, 6.2 mmol, 2.71 M in hexane) and 1-bromobu-
tane (0.68 mL, 6.32 mmol) followed by n-BuLi (2.30 mL, 6.2
mmol, 2.71 M in hexane) and bromine (0.61 mL, 12.0 mmol)
yielded an oil which crystallized from methanol to give 19c
(mp 66-72 °C, 0.875 g): IR (KBr) 1596, 1325, 1246, 1148, 850
1
cm-1; H NMR (CDCl3) δ 0.02 (9H, s), 0.91 (3H, t), 1.30-1.50
(3H, m), 1.60-1.69 (1H, m), 1.95 (1H, d, J ) 14.2 Hz), 2.39
(3H, s), 2.43-2.59 (1H, m), 2.80-2.95 (1H, m), 3.16 (1H, d, J
) 14.2 Hz), 6.84-6.97 (2H, m), 7.03-7.22 (4H, m), 7.33-7.38
(2H, d); 13C NMR (CDCl3) δ -0.6, 13.8, 21.6, 22.5, 26.4, 27.5,
38.9, 86.6, 123.4, 127.5, 128.8, 129.2, 130.9, 131.3, 131.4, 132.1,
145.0, 145.4; MS(EI) m/e (relative intensity) 313.08 (15), 311.08
(15), 229.07 (17), 117.07 (56), 73.05 (100). A portion was
recrystallized from ligroin to obtain an analytical sample (mp
69-72 °C). Anal. Calcd for C22H31BrO2SSi: C, 56.52; H, 6.68.
Found: C, 56.61; H, 6.72. The mother liquor was chromato-
graphed on silica gel using 1:15 ethyl acetate:petroleum ether
to yield additional 19c (1.15 g, total yield 72%).
Rea ction of 19a w ith TBAF . P r ep a r a tion of p-Tolyl
1-o-Tolylvin yl Su lfon e (23a ) a n d 7-Meth yl-7-(p-tolylsu l-
fon yl)bicyclo[4.2.0]octa -1,3,5-tr ien e (21a ). TBAF (2.3 mL,
1.0 M in acetonitrile) was added in 90 min to 19a (0.497 g,
1.17 mmol) in acetonitrile (8 mL). The mixture was diluted
with water and extracted with diethyl ether. The organic
phase was washed with water and saturated NaCl, dried over
MgSO4, and concentrated. Crystallization from methanol
yielded 23a (0.137 g, 43%): IR (KBr) 1313, 1147 cm-1; 1H NMR
(CDCl3) δ 1.93 (3H, s), 2.38 (3H, s), 5.76 (1H, s), 6.69 (1H, s),
6.92-7.24 (6H, m), 7.47 (2H, d); 13C NMR (CDCl3) δ 19.2 (q),
21.5 (q), 125.1 (d), 126.4 (t), 128.8 (d), 129.1 (d), 129.4 (d), 130.0
(d), 130.6 (d), 131.6 (s), 135.3 (s), 137.6 (s), 144.5 (s), 150.1 (s);
MS(EI) m/e (relative intensity) 272.09 (12), 117.07 (100);
HRMS calcd for C16H16O2S 272.0871, found 272.0864. Two
recrystallizations from methanol gave an analytical sample
of 23a (mp 90-92 °C). Anal. Calcd for C16H16O2S: C, 70.56;
H, 5.92. Found: C, 70.47; H, 5.97.
[o-[r-Br om o-r-(p -t olylsu lfon yl)p h en et h yl]b en zyl]t r i-
m eth ylsila n e (19d ). Sulfone 9 (3.00 g, 9.02 mmol) in THF
(60 mL) was alkylated with n-BuLi (3.45 mL, 9.3 mmol, 2.71
M in hexane) and benzyl bromide (1.2 mL, 10.1 mmol) followed
by reactions with n-BuLi (3.5 mL, 9.5 mmol, 2.71 M in hexane)
and bromine (0.95 mL, 19 mmol). Product workup and
crystallization from methanol yielded 19d as a white solid
(2.74 g, 60%, mp 129-131 °C): IR (KBr) 1596, 1322, 1247,
The mother liquor was chromatographed on silica gel using
1:9 ethyl acetate: petroleum ether. The first eluent contained
additional 23a (57 mg, 18%, total yield 61%). The next eluent
contained 21a (35 mg, 11%): IR (KBr) 2974, 2929, 1287, 1135
1
1148, 1082, 842 cm-1; H NMR (CDCl3) δ -0.04 (9H, s), 1.82
(1H, d, J ) 14.2 Hz), 2.41 (3H, s), 3.19 (1H, d, J ) 14.3 Hz),
4.00 (1H, d, J ) 16.7 Hz), 4.52 (1H, d, J ) 16.7 Hz), 6.82-
6.90 (1H, m), 7.05-7.25 (10H, m), 7.37-7.42 (2H, d); 13C NMR
(CDCl3) δ -0.6, 21.6, 26.5, 43.2, 85.5, 123.3, 126.7, 127.4, 127.9,
128.9, 129.5, 130.1, 130.7, 131.3, 132.3, 132.7, 134.9, 145.2,
145.2; MS(EI) m/e (relative intensity) 420.06 (2), 347.06 (5),
345.07 (5), 266.14 (8), 229.07 (13), 193.14 (60), 115.05 (22),
91.05 (24), 73.05 (100). An analytical sample (mp 129-130.5
°C) of 19d was obtained by recrystallization from ligroin. Anal.
Calcd for C25H29BrO2SSi: C, 59.87; H, 5.83. Found: C, 59.77;
H, 5.86.
1
cm-1; H NMR (CDCl3) δ 1.84 (3H, s), 2.42 (3H, s), 3.12 (1H,
d, J ) 14.5), 3.76 (1H, d, J ) 14.6), 7.01-7.69 (8H, m); 13C
NMR (CDCl3) δ 18.9, 21.6, 40.4, 69.3, 121.9, 123.4, 127.8, 129.2,
129.8, 129.9, 132.9, 141.8, 143.5, 144.5; MS(EI) m/e (relative
intensity) 272.09 (1), 117.07 (100), 115.06 (32), 91.06 (20);
HRMS calcd for C16H16O2S 272.0871, found 272.0876. Crys-
tallization from ligroin yielded an analytical sample of 21a (mp
103 °C). Anal. Calcd for C16H16O2S: C, 70.56; H, 5.92.
Found: C, 70.62; H, 5.93.
[o-[1-Br om o-1-(p -t olylsu lfon yl)-5-h exen yl]b en zyl]t r i-
m eth ylsila n e (19e). Alkylation of 9 (2.00 g, 6.01 mmol) using
n-BuLi (2.30 mL, 6.2 mmol, 2.71 M in hexane) and 5-bromo-
1-pentene (0.78 mL, 6.6 mmol) followed by n-BuLi (2.30 mL,
6.2 mmol, 2.71 M in hexane) and bromine (0.32 mL, 6.3 mmol)
and workup yielded 19e which was crystallized from methanol
(1.67 g, 58%, mp 110-113 °C): IR (KBr) 1596, 1323, 1246,
Rea ction of 19b w ith TBAF . P r ep a r a tion of 7-Eth yl-
7-(p-tolylsu lfon yl)-bicyclo[4.2.0]octa-1,3,5-tr ien e (21b) an d
p-Tolyl 1-o-Tolylp r op en yl Su lfon e (23b). To 19b (0.498 g,
1.13 mmol) in acetonitrile (10 mL) was added TBAF (2.3 mL,
2.3 mmol, 1.0 M in acetonitrile) in 45 min. After workup, the
product was crystallized from methanol to give 21b (0.140 g,
43%, mp 121-125 °C): IR (KBr) 2976, 2933, 1596, 1284, 1131
1
1
1147, 849 cm-1; H NMR (CDCl3) δ -0.02 (9H, s), 1.44-1.61
cm-1; H NMR (CDCl3) δ 0.92 (3H, t), 2.14 (1H, sextet), 2.31
(1H, m), 1.68-1.87 (1H, m), 1.93 (1H, d, J ) 14.2 Hz), 2.15
(2H, q), 2.40 (3H, s), 2.43-2.59 (1H, m), 2.82-2.97 (1H, m),
3.15 (1H, d, J ) 14.2 Hz), 4.95-5.07 (2H, m), 5.65-5.87 (1H,
m), 6.84-6.95 (2H, m), 7.04-7.23 (4H, m), 7.36 (2H, d); 13C
NMR (CDCl3) δ -0.6 (q), 21.6 (q), 24.7 (t), 26.4 (t), 33.3 (t),
38.7 (t), 86.6 (s), 115.6 (t), 123.4 (d), 127.5 (s), 128.9 (d), 129.2
(1H, sextet), 2.37 (3H, s), 3.18 (1H, d, J ) 14.7 Hz), 3.55 (1H,
d, J ) 14.7 Hz), 6.95-6.98 (1H, m), 7.10-7.15 (1H, m), 7.19-
7.26 (4H, m), 7.62 (2H, d); 13C NMR (CDCl3) δ 9.1, 21.5, 23.7,
36.9, 73.8, 122.9, 123.0, 127.6, 129.1, 129.6, 129.7, 133.2, 141.3,
142.3, 144.4; MS(EI) m/e (relative intensity) 131.09 (100),
116.06 (19), 115.06 (23), 91.05 (58). A portion of 21b, on

2092 J . Org. Chem., Vol. 63, No. 7, 1998
Lenihan and Shechter
crystallization from ligroin, yielded an analytical sample (mp
125-126 °C). Anal. Calcd for C17H18O2S: C, 71.30; H, 6.34.
Found: C, 71.31; H, 6.35.
(23e). To 19e (0.499 g, 1.04 mmol) in acetonitrile (10 mL) was
added in 50 min TBAF (2.1 mL, 2.1 mmol, 1.0 M in acetoni-
trile). After workup, the crude product was chromatographed
on silica gel using 1:15 ethyl acetate:ligroin. The first eluent
yielded 23e (72 mg, 22%): IR (neat film) 1640, 1597, 1313,
1301, 1147 cm-1; 1H NMR δ 1.87 (3H, s), 1.9-2.4 (4H, m), 2.40
(3H, s), 4.95-5.03 (2H, m), 5.69 (1H, m), 6.77 (1H, d), 7.04-
7.47 (8H, m); MS(EI) m/e (relative intensity) 171.11 (79),
143.08 (28), 129.06 (56), 105.06 (85); HRMS calcd for C20H22O2S
326.1340, found 326.1321.
The mother liquor was chromatographed on silica gel using
1:15 ethyl acetate:petroleum ether as solvent. The first eluent
gave 23b (48 mg, 15%) as an oil: IR (neat film) 1641, 1597,
1312, 1301, 1148, 588 cm-1; 1H NMR (CDCl3) δ 1.59 (3H, d, J
) 7.0 Hz), 1.80 (3H, s), 2.38 (3H, s), 6.82-6.86 (1H,m), 7.08-
7.30 (6H, m), 7.43 (2H, d); 13C NMR (CDCl3) δ 14.7, 18.9, 21.5,
125.4, 128.6, 129.0, 129.3, 129.6, 129.9, 131.0, 136.0, 137.9,
138.2, 142.8, 144.0; MS(EI) m/e (relative intensity) 286.10 (7),
131.09 (100), 116.06 (34), 115.05 (49), 91.05 (82); HRMS calcd
for C17H18O2S 286.1027, found 286.1029. The next eluent
contained additional 21b (37 mg, 11%, total yield 54%).
Rea ction of 19c w ith TBAF . P r ep a r a tion of 7-Bu tyl-
7-(p-tolylsu lfon yl)-bicyclo[4.2.0]octa-1,3,5-tr ien e (21c) an d
p-Tolyl 1-o-Tolyl-1-p en ten yl Su lfon e (23c). To 19c (0.500
g, 1.07 mmol) in acetonitrile (10 mL) was added TBAF (2.1
mL, 2.1 mmol, 1.0 M in acetonitrile) in 45 min. After workup,
the product was chromatographed on silica gel using 1:15 ethyl
acetate:petroleum ether. The first eluent yielded 23c (51 mg,
15%) as an oil: IR (KBr) 1639, 1597, 1313, 1302, 1148, 588
The second eluent contained 21e (168 mg, 50%) as an oil:
IR (neat film) 2936, 1640, 1597, 1457, 1311, 1300, 1288, 1148
1
cm-1; H NMR (CDCl3) δ 1.35-1.52 (2H, m), 1.99-2.35 (4H,
m), 2.39 (3H, s), 3.20 (1H, d, J ) 14.8 Hz), 3.54 (1H, d, J )
14.8 Hz), 4.89-4.98 (2H, m), 5.70 (1H, m), 6.94-6.97 (1H, m),
7.13-7.26 (5H, m), 7.58-7.62 (2H, d); 13C NMR (CDCl3) δ 21.5,
24.2, 30.1, 33.8, 37.8, 73.2, 115.1, 123.0, 123.1, 127.7, 129.1,
129.7, 129.8, 133.1, 137.8, 141.8, 142.2, 144.4; MS(EI) m/e
(relative intensity) 171.12 (20), 143.09 (18), 129.08 (100),
115.06 (41), 91.05 (50), 55.06 (24). The product was chromato-
graphed on silica gel using 1:9 ethyl acetate:ligroin. Anal.
Calcd for C20H22O2S: C, 73.58; H, 6.79. Found: C, 73.51; H,
6.80.
1
cm-1; H NMR (CDCl3) δ 0.84, (3H, t, J ) 7.2 Hz), 1.44 (2H,
sextet), 1.70-2.02 (2H, m), 1.83 (3H, s), 2.38 (3H, s), 6.80 (1H,
dd), 7.01-7.25 (6H, m), 7.40-7.46 (2H, br d); 13C NMR (CDCl3)
δ 13.7, 19.1, 21.4, 21.5, 31.0, 125.3, 128.7, 128.9, 129.3, 129.9,
131.2, 136.2, 138.3, 142.1, 142.7, 144.0; MS(EI) m/e (relative
intensity) 314.13 (3), 159.11 (35), 117.07 (100); HRMS calcd
for C19H22O2S 314.1340, found 314.1342.
The next eluent gave 21c (204 mg, 61%): IR (KBr) 2958,
2940, 1597, 1292, 1133 cm-1; 1H NMR (CDCl3) δ 0.84 (3H, m),
1.1-1.4 (4H, m), 2.0-2.4 (2H, m), 2.39 (3H, s), 3.21 (1H, d, J
) 14.8 Hz), 3.53 (1H, d, J ) 14.8 Hz), 6.91-6.97 (1H, m), 7.08-
7.23 (5H, m), 7.57-7.63 (2H, d); 13C NMR (CDCl3) δ 13.6, 21.4,
22.8, 26.8, 30.2, 37.6, 73.2, 122.8, 122.9, 127.5, 129.0, 129.5,
129.7, 133.1, 141.8, 142.1, 144.3; MS(EI) m/e (relative inten-
sity) 159.12 (21), 117.08 (100), 115.05 (36), 91.05 (43). Crystal-
lization from ligroin yielded an analytical sample of 21c (mp
89-91 °C). Anal. Calcd for C19H22O2S: C, 72.58; H, 7.05.
Found: C, 72.66; H, 7.04.
Rea ction of 19f w ith TBAF . P r ep a r a tion of 7-(2-
P r op yl)-7-(p -t olylsu lfon yl)b icyclo[4.2.0]oct a -1,3,5-t r i-
en e (21f) a n d 2-Meth yl-1-o-tolylp r op en yl p-Tolyl Su lfon e
(23f). To 19f (0.500 g, 1.10 mmol) in acetonitrile (10 mL) in
35 min was added TBAF (2.2 mL, 2.2 mmol, 1.0 M in
acetonitrile). Workup yielded an oil which solidified. Recrys-
tallization from methanol gave 21f as a white solid (0.138 g,
42%, mp 137-140 °C): IR (KBr) 1596, 1286, 1131, 1080 cm-1
;
1H NMR (CDCl3) δ 1.04 (3H, d, J ) 6.9 Hz), 1.21 (3H, d, J )
6.7 Hz), 2.33 (3H, s), 2.77 (1H, septet, J ) 6.8 Hz), 3.31 (2H,
s), 6.85 (1H, d), 7.04-7.26 (5H, m), 7.50 (2H, d); 13C NMR
(CDCl3) δ 19.4, 20.1, 21.5, 29.0, 35.4, 77.4, 122.8, 123.5, 127.5,
128.8, 129.3, 129.6, 133.8, 142.3, 142.6, 144.0; MS(EI) m/e
(relative intensity) 145.10 (100), 117.07 (38), 91.05 (30). One
recrystallization from ligroin yielded an analytical sample of
21f. Anal. Calcd for C18H20O2S: C, 71.97; H, 6.71. Found:
C, 72.04; H, 6.72.
Rea ction of 19d w ith TBAF . P r ep a r a tion of 7-Ben zyl-
7-(p-tolylsu lfon yl)-bicyclo[4.2.0]octa-1,3,5-tr ien e (21d) an d
2-Meth yl-r-(p-tolylsu lfon yl)stilben e (23d ). To 19d (0.501
g, 1.00 mmol) in acetonitrile (10 mL) was added TBAF (2.0
mL, 1.0 M in acetonitrile) in 45 min. The mixture was diluted
with water and extracted with diethyl ether. The organic layer
was washed with saturated NaCl, dried over MgSO4, and
concentrated to an oil from which 21d was obtained by
crystallization from methanol (0.168 g, mp 136-139 °C): IR
The mother liquor was chromatographed on silica gel. An
oil (94 mg) was obtained which NMR indicated to be 25% 21f
(additional yield of 21f: 24 mg, 7%, total yield: 49%) and 75%
23f (yield of 23f: 70 mg, 21%): 1H NMR (CDCl3) δ 1.55 (3H,
s), 2.02 (3H, s), 2.37 (3H, s), 2.43 (3H, s), 6.83-6.86 (1H, m),
7.0-7.2 (5H, m), 7.49-7.54 (2H, m).
[o-[Ch lor o(p -t olylsu lfon yl)m e t h yl]b e n zyl]t r im e t h -
ylsila n e (26) a n d [o-[Dich lor o(p-tolylsu lfon yl)m eth yl]-
ben zyl]tr im eth ylsila n e (27). To sulfone 9 (5.00 g, 15 mmol)
in THF (100 mL) at -78 °C was added n-BuLi (12.2 mL, 16.5
mmol, 1.35 M in hexane). After being warmed to room
temperature, the solution was cooled to -78 °C, and tert-butyl
hypochlorite (7.0 mL, 62 mmol) was added. The mixture was
warmed to room temperature and protected from bright light.
To the pale yellow solution were added two 1 mL portions of
tert-butyl hypochlorite, and the mixture became colorless. The
solution was diluted with 10% sodium bisulfite and extracted
twice with diethyl ether. The combined diethyl ether extracts
were washed with saturated NaCl, dried over MgSO4, and
concentrated. The material was recrystallized three times
from methanol to obtain 27 (2.49 g, 41%): IR (KBr) 1594, 1337,
1
(KBr) 1286, 1149 cm-1; H NMR (CDCl3) δ 2.40 (3H, s), 3.06
(1H, d, J ) 14.9 Hz), 3.40-3.50 (2H, two superimposed d, J )
14.9, 13.6 Hz), 3.63 (1H, d, J ) 13.5 Hz), 6.70 (1H, d), 6.95-
7.26 (10H, m), 7.64 (2H, d); 13C NMR (CDCl3) δ 21.5, 35.7, 36.0,
73.3, 122.8, 122.9, 126.7, 127.5, 127.8, 129.1, 129.7, 130.0,
130.3, 132.8, 134.7, 141.0, 142.1, 144.5; MS(EI) m/e (relative
intensity) 193.10 (91), 178.08 (45), 115.05 (100), 91.05 (55);
HRMS calcd for C22H20O2S 348.1184, found 348.1163. Recrys-
tallization from ligroin yielded an analytical sample of 21d
(mp 137.5-139.5 °C). Anal. Calcd for C22H20O2S: C, 75.83;
H, 5.79. Found: C, 75.90; H, 5.80.
The mother liquor was concentrated and chromatographed
on silica gel using 1:9 ethyl acetate:ligroin as solvent. The
first eluent contained 23d (60 mg, 17%) as an oil: IR (neat
1
1159, 849 cm-1; H NMR (CDCl3) δ 0.03 (9H, s), 2.44 (3H, s),
2.70 (2H, s), 6.97-7.73 (8H, m); 13C NMR (CDCl3) δ -0.8 (q),
21.7 (q), 26.8 (t), 100.7 (s), 123.6 (d), 128.3 (s), 129.1 (d), 129.3
(s), 130.6 (d), 131.9 (d), 131.9 (d), 132.2 (d), 143.7 (s), 146.2
(s); MS(EI) m/e (relative intensity) 247.03 (22), 245.04 (32),
73.05 (100). Additional crystallizations from methanol yielded
an analytical sample (mp 118-119.5 °C). Anal. Calcd for
1
film) 1627, 1597, 1312, 1142, 1087 cm-1; H NMR (CDCl3) δ
1.73 (3H, s), 2.40 (3H, s), 6.95-7.35 (11H, m), 7.49 (2H, d),
7.97 (1H, s); 13C NMR (CDCl3) δ 19.0, 21.6, 126.0, 128.6, 128.9,
129.3, 129.4, 129.9, 130.1, 130.3, 130.4, 131.1, 133.1, 135.7,
137.6, 138.2, 140.2, 144.2; MS(EI) m/e (relative intensity)
348.12 (11), 209.10 (13), 193.10 (100), 178.08 (38), 115.06 (51),
91.06 (23); HRMS calcd for C22H20O2S 348.1184, found 348.1158.
The next eluent contained additional 21d (36 mg; total yield
204 mg, 59%).
C
18H22Cl2O2SSi: C, 53.86; H, 5.52. Found: C, 53.55; H, 5.48.
Concentration of the mother liquors from the first two
crystallizations followed by crystallization from petroleum
ether gave 26 (0.62 g, 11%) as a solid: 1H NMR (CDCl3) δ 0.01
(9H, s), 1.98 (1H, d, J ) 14.5 Hz), 2.28 (1H, d, J ) 14.3 Hz),
2.46 (3H, s), 5.89 (1H, s), 6.94-7.41 (6H, m), 7.61 (2H, d).
Rea ction of 19e w ith TBAF . P r ep a r a tion of 7-(4-
P en t en yl-7-(p -t olylsu lfon yl)b icyclo[4.2.0]oct a -1,3,5-t r i-
en e (21e) a n d p-Tolyl 1-o-Tolyl-1,5-h exa d ien yl Su lfon e

[o-[Halo(p-tolylsulfonyl)alkyl]benzyl]trimethylsilane Conversion
J . Org. Chem., Vol. 63, No. 7, 1998 2093
7-Ch lor o-7-(p -t olylsu lfon yl)b icyclo[4.2.0]oct a -1,3,5-
tr ien e (28). TBAF (5.0 mL, 5.0 mmol, 1.0 M in acetonitrile)
was added in 45 min to 27 (979 mg, 2.44 mmol) in acetonitrile
(20 mL) at 0 °C. The mixture was stirred at room temperature
15 min, diluted with dichloromethane, washed with water,
dried over MgSO4, and concentrated. The oily solid obtained
was crystallized from methanol to yield 28 (374 mg, 51%),
which was recrystallized from methanol to give a sample
acetate:ligroin) to obtain an analytical sample: MS(EI) m/e
(relative intensity) 139.02 (36), 137.02 (100), 102.05 (22),
101.04 (21). Anal. Calcd for C15H13ClO2S: C, 61.54; H, 4.48.
Found: C, 61.12; H, 4.53.
Ack n ow led gm en t. We thank the National Science
Foundation for support of this research.
1
melting at 148-150 °C: IR (KBr) 1595, 1316, 1156 cm-1; H
Su p p or tin g In for m a tion Ava ila ble: NMR spectra (60
pages). This material is contained in libraries on microfiche,
immediately follows this article in the miocrofilm version of
the journal, and can be ordered from ACS; see any current
masthead page for ordering information.
NMR (CDCl3) δ 2.46 (3H, s), 3.62 (1H, d, J ) 14.7 Hz), 4.20
(1H, d, J ) 14.7 Hz), 7.03 (1H, d), 7.15 (1H, d), 7.26-7.44 (4H,
m), 7.81 (2H, d); 13C NMR (CDCl3) δ 21.7 (q), 45.7 (t), 79.9 (s),
122.2 (d), 123.5 (d), 128.8 (d), 129.5 (d), 130.7 (d), 131.5 (s),
132.1 (d), 140.4 (s), 141.6 (s), 145.7 (s). The product was then
recrystallized three times (using methanol and 1:4 ethyl
J O9705935