Efficient conversion of sulfones into β-keto sulfones by N-acylbenzotriazoles

Article abstract of DOI:10.1021/jo026636l

Acyclic sulfones 4a-f and alicyclic sulfone 7 react with readily available N-acylbenzotriazoles 3a-g (derived from aliphatic, aromatic, and heteroaromatic carboxylic acids) to provide the corresponding β-keto sulfones 5a-n and 8a-c, respectively, in good

Full text of DOI:10.1021/jo026636l

Efficien t Con ver sion of Su lfon es in to â-Keto Su lfon es by
N-Acylben zotr ia zoles§
Alan R. Katritzky,* Ashraf A. A. Abdel-Fattah, and Mingyi Wang
Center for Heterocyclic Compounds, Department of Chemistry, University of Florida,
Gainesville, Florida 32611-7200
katritzky@chem.ufl.edu
Received October 30, 2002
Acyclic sulfones 4a -f and alicyclic sulfone 7 react with readily available N-acylbenzotriazoles 3a -g
(derived from aliphatic, aromatic, and heteroaromatic carboxylic acids) to provide the corresponding
â-keto sulfones 5a -n and 8a -c, respectively, in good to excellent yields.
SCHEME 1
In tr od u ction
Sulfones are of great importance in organic synthesis.1
Among their derivatives, â-keto sulfones possess wide-
spread synthetic applications. â-Keto sulfones are utilized
as intermediates in the synthesis of, among others,
disubstituted acetylenes,2 olefins,2d allenes,3 vinyl sul-
fones,4 and polyfunctionalized 4H-pyrans.5 â-Keto sul-
fones are useful intermediates for the syntheses of
ketones6 by facile reductive elimination of the sulfonyl
group. In addition, â-keto sulfones are precursors for
optically active â-hydroxy sulfones.7 Certain â-keto sul-
fone derivatives exhibit fungicidal activity.8
Available routes to â-oxo-sulfones (Scheme 1) include
(i) alkylation of metallic arene sulfinates with either
R-halo-ketones9 or R-tosyloxy-ketones;10 (ii) oxidation of
â-oxo-sulfides,11 (iii) reactions of diazo sulfones with
aldehydes,12 (iv) reactions of sulfonyl chlorides with silyl
enol ethers,13 and (v) acylation of alkyl sulfones.
Method (v) is most commonly used to provide â-oxo-
sulfones; it typically employs esters14 or acid chlorides15
as acylating agents. The methodology quoted in ref 14a-c
is appropriate only when a readily available sulfone is
being used: the quoted yields of 60-94% (average 77%)
are based on the amount of ester utilized, whereas
recalculation based on the sulfone used gives yields of
17-45% (average 31%). The methodology quoted in refs
14e and 15b is appropriate only when a readily available
ester or acid chloride is being used: the quoted yields of
62-80% (average 71%) are based on the sulfone, whereas
yields based on ester or acid chloride are 35-53%
(average 44%). In the procedure of ref 14d, a 1:1 ratio of
reagents gave yields of 71-94%; however, the use of both
TMEDA and HMPA were required. Reference 15a needs
the formation of sulfone dianions.
§ Dedicated to our friend Professor Ameen Farouk M. Fahmy in
celebration of his 60th birthday and his 40 years of teaching and
research at Ain Shams University, Egypt.
(1) Simpkins, N. S. Sulfones in Organic Synthesis; Baldwin, J . E.,
Ed.; Pergamon Press: Oxford, 1993.
(2) (a) Lythgoe, B.; Waterhouse, I. Tetrahedron Lett. 1978, 29, 2625.
(b) Bartlett, P. A.; Green, F. R., III; Rose, E. H. J . Am. Chem. Soc.
1978, 100, 4852. (c) Mandai, T.; Yanagi, T.; Araki, K.; Morisaki, Y.;
Kawada, M.; Otera, J . J . Am. Chem. Soc. 1984, 106, 3670. (d) Ihara,
M.; Suzuki, S.; Taniguchi, T.; Tokunaga, Y.; Fukumoto, K. Tetrahedron
1995, 51, 9873.
(3) Baldwin, J . E.; Adlington, R. M.; Crouch, N. P.; Hill, R. L.; Laffey,
T. G. Tetrahedron Lett. 1995, 36, 7925.
(4) Sengupta, S.; Sarma, D. S.; Mondal, S. Tetrahedron: Asymmetry
1998, 9, 2311.
(5) (a) Marco, J .-L.; Ferna´ndez, I.; Khiar, N.; Ferna´ndez, P.; Romero,
A. J . Org. Chem. 1995, 60, 6678. (b) Marco, J . L. J . Org. Chem. 1997,
62, 6575.
(9) (a) Vennstra, G. E.; Zwaneburg, B. Synthesis 1975, 519. (b)
Wildeman, J .; van Leusen, A. M. Synthesis 1979, 733.
(10) Xie, Y.-Y.; Chen, Z.-C. Synth. Commun. 2001, 31, 3145.
(11) (a) Trost, B. M.; Curran, D. P. Tetrahedron Lett. 1981, 22, 1287.
(b) Fan, A.-L.; Cao, S.; Zhang, Z. J . Heterocycl. Chem. 1997, 34, 1657.
(12) Holmquist, C. R.; Roskamp, E. J . Tetrahedron Lett. 1992, 33,
1131.
(6) (a) Corey, E. J .; Chaykovsky, M. J . Am. Chem. Soc. 1964, 86,
1639. (b) Trost, B. M.; Arndt, H. C.; Strege, P. E.; Verhoeven, T. R.
Tetrahedron Lett. 1976, 27, 3477. (c) Kurth, M. J .; O’Brien, M. J . J .
Org. Chem. 1985, 50, 3846. (d) Fuju, M.; Nakamura, K.; Mekata, H.;
Oka, S.; Ohno, A. Bull. Chem. Soc. J pn. 1988, 61, 495. (e) Sengupta,
S.; Sarma, D. S.; Mondal, S. Tetrahedron 1998, 54, 9791. (f) Guo, H.;
Zhang, Y. Synth. Commun. 2000, 30, 2564.
(7) (a) Svatosˇ, A.; Hunˇkova´, Z.; Krˇen, V.; Hoskovec, M.; Sˇaman, D.;
Valterova´, I.; Vrkocˇ, J .; Koutek, B. Tetrahedron: Asymmetry 1996, 7,
1285. (b) Bertus, P.; Phansavath, P.; Ratovelomanana-Vidal, V.; Geneˆt,
J .-P.; Touati, A. R.; Homri, T.; Hassine, B. B. Tetrahedron: Asymmetry
1999, 10, 1369. (c) Gotor, V.; Rebolledo, F.; Liz, R. Tetrahedron:
Asymmetry 2001, 12, 513.
(13) Kamigata, N.; Udodaira, K.; Shimizu, T. J . Chem. Soc., Perkin
Trans. 1 1997, 783.
(14) (a) Field, L.; Lawson, J . E.; McFarland, J . W. J . Am. Chem.
Soc. 1956, 78, 4389. (b) Becker, H.-D.; Russell, G. A. J . Org. Chem.
1963, 28, 1896. (c) House, H. O.; Larson, J . K. J . Org. Chem. 1968, 33,
61. (d) Kondo, K.; Tunemoto, D. Tetrahedron Lett. 1975, 17, 1397. (e)
Ogura, K.; Yahata, N.; Hashizume, K.; Tsuyama, K.; Takahashi, K.;
Iida, H. Chem. Lett. 1983, 767. (f) Lutz, M.; Linden, A.; Abou-Hadeed,
K.; Hansen, H.-J . Helv. Chim. Acta 1999, 82, 372.
(15) (a) Thomsen, M. W.; Handwerker, B. M.; Katz, S. A.; Belser,
R. B. J . Org. Chem. 1988, 53, 906. (b) Lenihan, B. D.; Shechter, H. J .
Org. Chem. 1998, 63, 2072.
(8) Wolf, W. M. J . Mol. Struct. 1999, 474, 113.
10.1021/jo026636l CCC: $25.00 © 2003 American Chemical Society
Published on Web 01/29/2003
J . Org. Chem. 2003, 68, 1443-1446
1443

Katritzky et al.
SCHEME 2
SCHEME 3
fone 4f under the same reaction conditions provided the
corresponding diacylated sulfone 6 in 44% yield based
on acylating agent 3b, instead of the expected monoacy-
lated product of type 5 (Scheme 3). The conceptually
similar acylation of dimethyl sulfone with N-acylimida-
zoles reported by Ibarra et al.21 utilized 5 molar equiv of
both the starting sulfone and base to afford seven
examples of â-keto sulfones; the average yield was 61%
based on the acylating agent.
Application of our methodology to heterocyclic sulfone
7 (sulfolane) allowed the synthesis of previously unre-
ported â-keto sulfones 8a -c in 72-81% yields (Scheme
3).
TABLE 1. P r ep a r a tion of â-Keto Su lfon es 5a -n via
C-Acyla tion of Alk yl Su lfon es w ith N-Acylben zotr ia zoles
entry
R
R1
R2
yield (%)
5a
5b
5c
5d
5e
5f
5g
5h
5i
5j
5k
5l
5m
5n
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
Ph
CHdCH2
CHdCH2
CH3
CH3
CH3
H
95
92
83
89
96
85
90
87
81
86
83
93
79
73
3-ClC6H4
2-pyridinyl
2-furyl
(CH3)2CHCH2
2-thienyl
Ph
4-CH3C6H4
2-pyridinyl
2-furyl
(CH3)2CHCH2
2-thienyl
Ph
The structures of compounds 5a -n , 6, and 8a -c were
supported by NMR spectrometry and elemental analyses.
1
The H NMR spectra of the â-oxo-sulfones 5a -n , 6, and
8a -c each showed a characteristic signal in the region
4.52-7.36 ppm, which was assigned to the proton at-
tached to a carbon flanked between sulfonyl and carbonyl
groups. In the 13C NMR spectra, the newly formed
carbonyl group in compounds 5a -n , 6, and 8a -c exhib-
ited signals in the region 180.2-199.8 ppm.
H
CH3
H
CH3CH2
CH3
2-thienyl
N-Acylbenzotriazoles have been used as effective re-
agents for the N-acylation of amines,16 C-acylation of
ketones,17 and O-acylation of aldehydes.18 We have
recently employed N-acylbenzotriazoles in an efficient
synthesis of â-keto nitriles from primary and secondary
alkyl nitriles.19 As a further application of N-acylbenzo-
triazoles, we now report a convenient preparation of
â-keto sulfones 5a -n and 8a -c in yields of 70-96%
(average 83%) based on using the reagent in a 1:1 ratio.
For optimum yields, the reactions of N-acylbenzotria-
zoles 3 with sulfones required 2 molar equiv of n-BuLi,
since the â-keto sulfones formed are rapidly deprotonated
by unreacted carbanions under the reaction conditions.
For 4a , the use of 1.2 equiv of base under the same
reaction conditions provided the acylated sulfone 5a in
62% yield. The generality of this method has been tested
by using N-acylbenzotriazoles 3 derived from aliphatic,
aromatic, and heteroaromatic acids and a variety of
sulfones.
Resu lts a n d Discu ssion
In summary, we have developed a convenient and
general method for the synthesis of aliphatic, aromatic,
and heteroaromatic ketones of type 5 and 8 via N-
acylbenzotriazoles 3. This approach uses sulfone and
readily available N-acylbenzotriazole in a 1:1 ratio and
affords yields that range from 70% to 96% (Schemes 2
and 3 and Table 1), thus demonstrating the potential of
N-acylbenzotriazoles 3 as effective C-acylation reagents,
particularly when it is advantageous to use sulfone and
acylating reagent in stochiometic ratio.
Treatment of the lithio-derivatives of sulfones 4a -f
(generated by the lithiation of the sulfones with n-BuLi)
at -78 °C with N-acylbenzotriazoles 3a -g, which were
prepared from the corresponding carboxylic acids 2a -g
and 1-(methylsulfonyl)benzotriazole 1 as previously re-
ported16 (Scheme 2), gave aliphatic, aromatic, and het-
eroaromatic â-oxo-sulfones 5a -n (Scheme 2 and Table
1). This synthetic route improved the previously re-
ported20 yield of compound 5a from 63% to 95% and
afforded previously unreported â-oxo-sulfones 5b-n in
isolated yields of 73-96%. Exceptionally, the reaction of
N-(4-methylbenzoyl)benzotriazole 3b with dimethyl sul-
Exp er im en ta l Section
Gen er a l. Melting points were determined on a hot stage
apparatus and are uncorrected. NMR spectra were recorded
in CDCl3 with tetramethylsilane as internal standard for 1H
(300 MHz) or solvent as the internal standard for 13C (75 MHz).
Microanalyses were performed on elemental analyzer. Anhy-
drous THF was obtained by distillation immediately prior to
(16) Katritzky, A. R.; He, H.-Y.; Suzuki, K. J . Org. Chem. 2000, 65,
8210.
(17) Katritzky, A. R.; Pastor, A. J . Org. Chem. 2000, 65, 3679.
(18) Katritzky, A. R.; Pastor, A.; Voronkov, M. V. J . Heterocycl.
Chem. 1999, 36, 777.
(19) Katritzky, A. R.; Abdel-Fattah, A. A. A.; Wang, M. Unpublished
work.
(20) Kaiser, E. M.; Solter, L. E.; Schwarz, R. A.; Beard, R. D.;
Hauser, C. R. J . Am. Chem. Soc. 1971, 93, 4237.
(21) Ibarra, C. A.; Rodriguez, R. C.; Monreal, M. C. F.; Navarro, F.
J . G.; Tesorero, J . M. J . Org. Chem. 1989, 54, 5620.
1444 J . Org. Chem., Vol. 68, No. 4, 2003

Conversion of Sulfones into â-Keto Sulfones
use. Column chromatography was conducted with silica gel
200-425 mesh. BtSO2CH3 (1) and N-acylbenzotriazoles 3a -g
were prepared according to literature procedures.16
Hz, 1H), 2.42 (s, 3H), 1.56 (d, J ) 6.9 Hz, 3H). 13C NMR δ
191.9, 145.3, 136.0, 134.1, 133.7, 129.8, 129.5, 129.3, 128.8,
64.8, 21.7, 13.2. Anal. Calcd for C16H16O3S: C, 66.64; H, 5.59.
Found: C, 66.71; H, 5.78.
Gen er a l P r oced u r es for th e P r ep a r a tion of â-Keto
Su lfon es 5a -l. A solution of the alkyl sulfone 4 (2 mmol) in
anhydrous THF (15 mL) was cooled to -40 °C under nitrogen
and thereafter treated dropwise with n-BuLi (2.6 mL of 1.55
M in hexane, 4 mmol) to afford a yellow mixture, which was
stirred at this temperature for 1 h. After the mixture cooled
to -78 °C, a solution of N-acylbenzotriazole 3 (2 mmol) in THF
(10 mL) was slowly added. The reaction was allowed to warm
to room temperature while stirring overnight, quenched by the
addition of saturated NH4Cl, and extracted with EtOAc. The
organic extracts were combined, washed with brine and water,
and dried over MgSO4. After evaporation under vacuum, the
residue was purified by flash chromatography (hexanes/EtOAc,
5:1) to afford the desired product 5.
1,2-Dip h en yl-2-(p h en ylsu lfon yl)-1-eth a n on e (5a ). Col-
orless microcrystals (95%), mp 118-120 °C, (lit.20 138-140 °C).
1H NMR δ 7.87 (d, J ) 7.4 Hz, 2H), 7.64 (d, J ) 8.0 Hz, 2H),
7.61-7.51 (m, 2H), 7.43-7.28 (m, 9H), 6.15 (s, 1H). 13C NMR
δ 190.7, 136.9, 136.0, 134.0, 133.9, 130.4, 130.3, 129.7, 128.9,
128.8, 128.7, 128.5, 128.4, 76.2. Anal. Calcd for C20H16O3S: C,
71.41; H, 4.79. Found: C, 71.07; H, 4.92.
2-(P h en ylsu lfon yl)-1-(2-pyr idin yl)-1-pr opan on e (5i). Col-
1
orless plates (81%), mp 79-81 °C. H NMR δ 8.60 (d, J ) 4.3
Hz, 1H), 8.02 (d, J ) 7.8 Hz, 1H), 7.86-7.80 (m, 3H), 7.62-
7.46 (m, 4H), 6.27 (q, J ) 7.0 Hz, 1H), 1.60 (d, J ) 7.0 Hz,
3H). 13C NMR δ 193.9, 151.9, 148.9, 137.4, 137.1, 133.8, 129.4,
128.8, 127.7, 122.6, 61.8, 12.1. Anal. Calcd for C14H13O3S: C,
61.07; H, 4.76; N, 5.09. Found: C, 60.86; H, 4.84; N, 4.79.
1-(2-F u r yl)-2-(p h en ylsu lfon yl)-1-p r op a n on e (5j). Color-
1
less needles (86%), mp 93-95 °C. H NMR δ 7.81 (d, J ) 7.8
Hz, 2H), 7.67-7.50 (m, 4H), 7.32 (d, J ) 3.6 Hz, 1H), 6.57 (d,
J ) 3.3 Hz, 1H), 4.97 (q, J ) 7.0 Hz, 1H), 1.56 (d, J ) 7.0 Hz,
3H). 13C NMR δ 180.2, 151.9, 147.8, 136.2, 134.1, 129.6, 128.9,
119.9, 113.1, 65.5, 12.0. Anal. Calcd for C13H12O4S: C, 59.08;
H, 4.58. Found: C, 59.03; H, 4.73.
4-Meth yl-1-(p h en ylsu lfon yl)-2-p en ta n on e (5k ). Color-
less plates (83%), mp 44-46 °C. 1H NMR δ 7.89 (d, J ) 7.4
Hz, 2H), 7.71-7.56 (m, 3H), 4.14 (s, 2H), 2.58 (d, J ) 6.7 Hz,
2H), 2.18-2.05 (m, 1H), 0.91 (d, J ) 6.7 Hz, 6H). 13C NMR δ
197.7, 138.6, 134.2, 129.3, 128.2, 66.9, 53.1, 23.9, 22.2. Anal.
Calcd for C12H16O3S: C, 59.98; H, 6.71. Found: C, 60.03; H,
7.03.
2-(P h en ylsu lfon yl)-1-(2-th ien yl)-1-eth a n on e (5l). Color-
less plates (92%), mp 79-80 °C. 1H NMR δ 7.90 (d, J ) 7.7
Hz, 2H), 7.81 (d, J ) 3.9 Hz, 1H), 7.76 (d, J ) 4.9 Hz, 1H),
7.70-7.65 (m, 1H), 7.59-7.54 (m, 2H), 7.17 (dd, J ) 3.9, 4.9
Hz, 1H), 4.63 (s, 2H). 13C NMR δ 180.1, 143.1, 138.4, 136.4,
135.2, 134.3, 129.2, 128.7, 128.5, 64.4. Anal. Calcd for
1-(3-Ch lor op h en yl)-2-p h en yl-2-(p h en ylsu lfon yl)-1-eth -
a n on e (5b). Colorless microcrystals (92%), mp 127-129 °C.
1H NMR δ 7.84 (t, J ) 1.9 Hz, 1H), 7.73 (dt, J ) 1.2, 7.8 Hz,
1H), 7.65-7.57 (m, 3H), 7.51-7.28 (m, 9H), 6.08 (s, 1H). 13C
NMR δ 189.5, 137.5, 136.5, 135.2, 134.1, 133.9, 130.3, 130.2,
130.1, 129.8, 129.0, 128.7, 128.4, 128.1, 126.8, 76.1. Anal. Calcd
for C20H15ClO3S: C, 64.77; H, 4.08. Found: C, 64.65; H, 4.03.
2-P h e n yl-2-(p h e n ylsu lfon yl)-1-(2-p yr id in yl)-1-e t h a -
C
12H10O3S2: C, 54.12; H, 3.78. Found: C, 53.91; H, 3.60.
1
n on e (5c). Colorless plates (83%), mp 92-94 °C. H NMR δ
Gen er a l P r oced u r es for th e P r ep a r a tion of â-Keto
8.61 (d, J ) 4.3 Hz, 1H), 8.06 (d, J ) 7.8 Hz, 1H), 7.79 (t, J )
7.7 Hz, 1H), 7.65 (d, J ) 7.4 Hz, 2H), 7.56 (t, J ) 7.5 Hz, 1H),
7.47-7.36 (m, 6H), 7.32-7.24 (m, 3H). 13C NMR δ 191.5, 151.6,
148.9, 137.3, 137.1, 133.7, 130.7, 129.7, 129.2, 128.5, 128.4,
128.3, 127.9, 122.7, 71.8. Anal. Calcd for C19H15NO3S: C, 67.64;
H, 4.48; N, 4.15. Found: C, 67.88; H, 4.63; N, 4.00.
Su lfon es 5m ,n , 6, a n d 8a -c. A solution of the alkyl sulfone
(2 mmol) in anhydrous THF (15 mL) was cooled to 0 °C under
nitrogen and thereafter treated dropwise with n-BuLi (2.6 mL
of 1.55 M in hexane, 4 mmol) to afford a yellow mixture, which
was warmed to room temperature and stirred at this temper-
ature for 1 h. After the mixture cooled to -78 °C, a solution of
N-acylbenzotriazole 3 (2 mmol) in THF (10 mL) was slowly
added. The reaction was allowed to warm to room temperature
while stirring overnight, quenched by the addition of saturated
NH4Cl, and extracted with EtOAc. The organic extracts were
combined, washed with brine and water, and dried over
MgSO4. After evaporation under vacuum, the residue was
purified by flash chromatography (hexanes/EtOAc, 5:1) to
afford the desired product.
1-(2-Fu r yl)-2-ph en yl-2-(ph en ylsu lfon yl)-1-eth an on e (5d).
1
Colorless needles (89%), mp 133-135 °C. H NMR δ 7.63 (d,
J ) 8.0 Hz, 2H), 7.58 (d, J ) 7.0 Hz, 2H), 7.43-7.25 (m, 8H),
6.54-6.52 (m, 1H), 6.05 (s, 1H). 13C NMR δ 178.7, 151.7, 147.6,
136.6, 134.0, 130.5, 130.1, 129.5, 128.6, 128.4, 128.1, 119.6,
113.2, 75.1. Anal. Calcd for C18H14O4S: C, 66.24; H, 4.32.
Found: C, 65.88; H, 4.35.
4-Meth yl-1-ph en yl-1-(ph en ylsu lfon yl)-2-pen tan on e (5e).
1
Colorless plates (96%), mp 103-105 °C. H NMR δ 7.61-7.56
2-(Eth ylsu lfon yl)-1-p h en yl-1-p r op a n on e (5m ). Colorless
(m, 3H), 7.43-7.23 (m, 7H), 5.24 (s, 1H), 2.58 (dd, J ) 17.2,
6.6 Hz, 1H), 2.43 (dd, J ) 17.2, 6.9 Hz, 1H), 2.19-2.06 (m,
1H), 0.87 (d J ) 6.7 Hz, 3H), 0.82 (d, J ) 6.7 Hz, 3H). 13C
NMR δ 199.8, 136.6, 133.9, 130.3, 129.8, 129.5, 128.6, 128.4,
127.7, 79.5, 53.4, 24.0, 22.2, 22.1. Anal. Calcd for C18H20O3S:
C, 68.33; H, 6.37. Found: C, 68.36; H, 6.51.
1
microcrystals (79%), mp 35-37 °C. H NMR δ 8.06-8.02 (m,
2H), 7.68-7.62 (m, 1H), 7.56-7.50 (m, 2H), 5.03 (q, J ) 7.1
Hz, 1H), 3.21-3.10 (m, 2H), 1.74 (d, J ) 7.1 Hz, 3H), 1.39 (t,
J ) 7.6 Hz, 3H). 13C NMR δ 193.8, 135.7, 134.4, 129.2, 128.9,
63.5, 43.6, 13.3, 5.0. Anal. Calcd for C11H14O3S: C, 58.38; H,
6.24. Found: C, 58.23; H, 6.31.
1-(2-Th ien yl)-2-(ph en ylsu lfon yl)-3-bu ten -1-on e (5f). Col-
orless plates (85%), mp 88-90 °C. 1H NMR δ 7.85-7.81 (m,
3H), 7.75 (dd, J ) 5.0, 1.1 Hz, 1H), 7.69-7.63 (m, 1H), 7.56-
7.51 (m, 2H), 7.18-7.15 (m, 1H), 6.04-5.92 (m, 1H), 5.51-
5.37 (m, 3H). 13C NMR δ 182.6, 143.2, 136.4, 136.3, 134.4,
134.3, 130.1, 128.7, 128.6, 126.5, 125.2, 76.0. Anal. Calcd for
2-(Meth ylsu lfon yl)-1-(2-th ien yl)-1-eth a n on e (5n ). Color-
1
less plates (73%), mp 98-100 °C. H NMR δ 7.85 (d, J ) 3.9
Hz, 1H), 7.82 (d, J ) 4.9 Hz, 1H), 7.20-7.23 (m, 1H), 4.52 (s,
2H), 3.16 (s, 3H). 13C NMR δ 181.3, 142.9, 137.1, 135.4, 128.9,
62.2, 41.7. Anal. Calcd for C11H14O3S: C, 41.16; H, 3.95.
Found: 41.55; H, 3.71.
C
14H12O3S2: C, 57.51; H, 4.14. Found: C, 57.13; H, 4.10.
1-(4-Meth ylp h en yl)-2-{[2-(4-m eth ylp h en yl)-2-oxoeth yl]-
su lfon yl}-1-eth a n on e (6). Colorless needles (44%), mp 137-
1-P h en yl-2-(p h en ylsu lfon yl)-3-bu ten -1-on e (5g). Color-
1
less prisms (90%), mp 99-101 °C. H NMR δ 7.98 (d, J ) 7.6
Hz, 2H), 7.83 (d, J ) 7.4 Hz, 2H), 7.69-7.47 (m, 6H), 6.05-
5.93 (m, 1H), 5.64 (d, J ) 8.9 Hz, 1H), 5.50-5.41 (m, 2H). 13C
NMR δ 190.6, 136.6, 136.1, 134.2, 134.1, 130.1, 129.0, 128.8,
128.7, 127.1, 125.1, 74.4. Anal. Calcd for C16H14O3S: C, 67.11;
H, 4.93. Found: C, 66.76; H, 5.13.
1-(4-Met h ylp h en yl)-2-(p h en ylsu lfon yl)-1-p r op a n on e
(5h ). Colorless plates (87%), mp 87-89 °C. 1H NMR δ 7.87 (d,
J ) 7.9 Hz, 2H), 7.79 (d, J ) 7.9 Hz, 2H), 7.67-7.62 (m, 1H),
7.54-7.49 (m, 2H), 7.27 (d, J ) 7.6 Hz, 2H), 5.15 (q, J ) 6.9
1
139 °C. H NMR δ 7.86 (d, J ) 8.1 Hz, 4H), 7.30 (d, J ) 8.0
Hz, 4H), 4.98 (s, 4H), 2.43 (s, 6H). 13C NMR δ 188.9, 145.9,
133.2, 129.7, 128.9, 59.7, 21.8. Anal. Calcd for C18H18O4S: C,
65.43; H, 5.49. Found: C, 65.41; H, 5.77.
2-Ben zoyltetr a h yd r oth iop h en e-1,1-d ion e (8a ). Colorless
plates (81%), mp 83-85 °C. 1H NMR δ 8.09 (d, J ) 7.6 Hz,
2H), 7.66-7.61 (m, 1H), 7.55-7.50 (m, 2H), 4.90 (t, J ) 7.6
Hz, 1H), 3.24-3.11 (m, 2H), 2.90-2.82 (m, 1H), 2.43-2.21 (m,
3H). 13C NMR δ 190.0, 136.2, 134.3, 129.0, 128.9, 65.3, 52.6,
J . Org. Chem, Vol. 68, No. 4, 2003 1445

Katritzky et al.
26.0, 20.6. Anal. Calcd for C11H12O3S: C, 58.91; H, 5.39.
Found: C, 58.95; H, 5.38.
5.0 Hz, 1H), 4.71 (t, J ) 7.6 Hz, 1H), 3.27-3.09 (m, 2H), 2.87-
2.77 (m, 1H), 2.46-2.33 (m, 2H), 2.30-2.17 (m, 1H). 13C NMR
δ 182.4, 143.8, 136.1, 134.3, 128.8, 66.6, 52.3, 25.6, 20.5. Anal.
Calcd for C9H10O3S2: C, 46.94; H, 4.38. Found: C, 47.22; H,
4.3
2-(4-Meth ylben zoyl)tetr ah ydr oth ioph en e-1,1-dion e (8b).
1
Colorless plates (77%), mp 94-96 °C. H NMR δ 7.98 (d, J )
8.1 Hz, 2H), 7.33 (d, J ) 8.1 Hz, 2H), 4.87 (t, J ) 7.5 Hz, 1H),
3.23-3.08 (m, 2H), 2.89-2.81 (m, 1H), 2.43 (s, 3H), 2.40-2.17
(m, 3H). 13C NMR δ 189.5, 145.5, 133.9, 129.7, 129.1, 65.2,
52.6, 25.9, 21.8, 20.6. Anal. Calcd for C12H14O3S: C, 60.48; H,
5.92. Found: C, 60.38; H, 6.14.
Su p p or tin g In for m a tion Ava ila ble: General procedure
and characterization data for compounds 5a -n , 6, and 8a -c.
This material is available free of charge via the Internet at
http://pubs.acs.org.
2-(2-Th ien ylca r bon yl)tetr a h yd r oth iop h en e-1,1-d ion e
1
(8c). Colorless plates (72%), mp 100-102 °C. H NMR δ 7.94
(d, J ) 3.8 Hz, 1H), 7.78 (d, J ) 5.0 Hz, 1H), 7.21 (dd, J ) 3.8,
J O026636L
1446 J . Org. Chem., Vol. 68, No. 4, 2003