Highly regioselective and stereoselective radical addition of p-TsBr to α-allenic alcohols and their elimination reaction: Synthesis of β-p-tosyl-substituted α,β-unsaturated ketones

Article abstract of DOI:10.1081/SCC-120014030

Regio- and stereoselective radical addition of α-allenic alcohols with p-TsBr in the presence of a catalytic amount of AIBN afforded (E)-γ-bromo-β-sulfonyl allylic alcohols in moderate yields. The base-promoted 1,4-elimination followed by isomerization to

Full text of DOI:10.1081/SCC-120014030

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HIGHLY REGIOSELECTIVE AND STEREOSELECTIVE
RADICAL ADDITION OF p-TsBr TO α-ALLENIC ALCOHOLS
AND THEIR ELIMINATION REACTION: SYNTHESIS OF β-p-
TOSYL-SUBSTITUTED α,β-UNSATURATED KETONES
a
a
a
Suk-Ku Kang , Byung-Su Ko & Dong-Min Lee
a
Department of Chemistry and Institute for Basic Sciences , Sungkyunkwan University ,
Suwon, 440-746, Korea
Published online: 16 Aug 2006.
To cite this article: Suk-Ku Kang , Byung-Su Ko & Dong-Min Lee (2002) HIGHLY REGIOSELECTIVE AND STEREOSELECTIVE
RADICAL ADDITION OF p-TsBr TO α-ALLENIC ALCOHOLS AND THEIR ELIMINATION REACTION: SYNTHESIS OF β-p-TOSYL-
SUBSTITUTED α,β-UNSATURATED KETONES, Synthetic Communications: An International Journal for Rapid Communication of
Synthetic Organic Chemistry, 32:21, 3263-3271, DOI: 10.1081/SCC-120014030
To link to this article: http://dx.doi.org/10.1081/SCC-120014030
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SYNTHETIC COMMUNICATIONS
Vol. 32, No. 21, pp. 3263–3271, 2002
HIGHLY REGIOSELECTIVE AND
STEREOSELECTIVE RADICAL ADDITION
OF p-TsBr TO a-ALLENIC ALCOHOLS
AND THEIR ELIMINATION
REACTION: SYNTHESIS OF
b-p-TOSYL-SUBSTITUTED
a,b-UNSATURATED KETONES
Suk-Ku Kang,* Byung-Su Ko, and Dong-Min Lee
Department of Chemistry and Institute for Basic
Sciences, Sungkyunkwan University,
Suwon 440-746, Korea
ABSTRACT
Regio- and stereoselective radical addition of a-allenic
alcohols with p-TsBr in the presence of a catalytic amount
of AIBN afforded (E)-g-bromo-b-sulfonyl allylic alcohols in
moderate yields. The base-promoted 1,4-elimination followed
by isomerization to give b-sulfonyl-a,b-unsaturated ketones is
described.
Key Words: Radical addition reactions; p-TsBr; a-Allenic
alcohols; 1,4-Elimination; Tosyl-substituted a,b-unsaturated
ketones
*
Corresponding author. E-mail: skkang@chem.skku.ac.kr
263
3
DOI: 10.1081/SCC-120014030
Copyright & 2002 by Marcel Dekker, Inc.
0039-7911 (Print); 1532-2432 (Online)
www.dekker.com

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3
264
KANG, KO, AND LEE
Although the radical chemistry of sulfonyl halides has been extensively
investigated, and has concentrated on the readily available sulfonyl
[1]
chlorides, much less work has been done with relatively stable, but less
[
2]
readily available sulfonyl bromides. Most of the work has involved the
free-radical addition of sulfonyl halides to alkenes and alkynes. However,
[
3]
the radical addition reaction of sulfonyl halides to allenes is rare, and the
reason is explained by the complexity associated with the addition reaction
to allenes in terms of chemo-, regio-, and stereoselectivity. The radical
cyclization of enallenes with p-TsBr to form five-membered ring system is
[
3a]
known.
which is highly reactive and unstable, to various allenes have been
Alternatively, the light-initiated addition of sulfonyl iodides,
[4]
reported. The photo-induced addition of sulfonyl iodides to allenes yielded
a mixture of products including the two 1 : 1 adducts resulting from attack
by the sulfonyl radical on both the central and terminal positions of the
allenic unit. The product distribution was highly dependent on the
substituents attached to the allene and reaction conditions, even if in
some cases the products derived from central attack on allene bearing one
[
4]
or more substituents were formed. Recently we have reported radical
addition of p-toluenesulfonyl bromide to simple terminal allenes and allenic
alcohols and sulfonamides in the presence of AIBN to give regioselective
and stereoselective adducts (E)-allylic bromides and/or the cyclized
[5,6]
ethers.
Our ongoing programs to utilize radical addition of p-TsBr to
allenic alcohols we reasoned that g-bromo-b-tosyl substituted (E)-allylic
alcohols from a-allenic alcohol and p-TsBr reaction could be intermediates
for organic synthesis and 1,4-elimination would give (E)-b-tosyl-substituted
a,b-unsaturated ketones, which is shown in Scheme 1. The resulting enones
and unsaturated sulfones could be useful as a Michael acceptor and a
[
2]
dienophile in Diels–Alder reaction. Herein we wish to report the regio-
selective radical addition of p-TsBr to the allenic alcohols and their 1,4-
elimination to form tosyl-substituted a,b-unsaturated enones.
The results of regioselective and stereoselective radical addition
a-allenic alcohols with p-TsBr in the presence of AIBN to give g-bromo-
b-sulfonyl allylic alcohols to form g-bromo-b-tosyl substituted (E)-allylic
alcohols are summarized in Table 1. The a-hydroxyallene 1a reacted
with p-TsBr in the presence of a catalytic amount of AIBN in toluene at
ꢀ
90 C for 2 h to afford the (E)-adduct as a sole product 2a in 75% yield
Scheme 1.

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b-p-TOSYL-SUBSTITUTED a,b-UNSATURATED KETONES
3265
Table 1. Radical Addition of p-TsBr to a-Allenic
Alcohols
a-Allenic
Alcohols
Radical
Adducts
Isolated
Yield (%)
Entry
1
75
2
3
71
71
4
5
6
7
73
75
70
67
(Entry 1 in Table 1). The stereochemistry of 2a was unambiguously deter-
mined by the observation of a nOe effect between vinyl proton and aromatic
1
[7]
protons in H NMR. Under the same conditions for a-hydroxyallene 1b
treated with p-TsBr gave (E)-tosyl-substituted alcohol 2b in 71% yield
(
Entry 2). The alkyl-substituted a-hydroxyallenes 1c and 1d were reacted
with p-TsBr to give the corresponding allylic bromides 2c and 2d in 71 and
3% yields, respectively (Entries 3 and 4). When the cyclohexyl-substituted
7

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266
KANG, KO, AND LEE
Table 2. Optimum Conditions for 1,4-Elimination
ꢀ
Entry
Base
Solvent
Time (h)
Temp. ( C)
Yield (%)
1
2
3
4
5
6
K CO (1.1 equiv.)
2
THF
THF
THF
THF
THF
Toluene
2
2
2
3
3
3
40
40
rt
rt
rt
48
50
0
68
66
67
60
3
2
K CO
3
(5 equiv.)
NaH (1.1 equiv.)
TEA (1.1 equiv.)
TEA (2 equiv.)
TEA (1.1 equiv.)
rt
rt
7
TEA (1.1 equiv.)
DMF
3
a-hydroxyallene 1e was treated with p-TsBr in the presence of AIBN the
E)-adduct 2e was afforded (Entry 5). The aryl-substituted a-hydroxyallenes
(
1
2
f and 1g were coupled with p-TsBr under the same conditions to provide
and 2g in 70 and 67% yields, respectively (Entries 6 and 7).
To find optimum conditions for 1,4-elimination of the (E)-adduct 2f, a
[7]
f
series of experiments has been carried out (Table 2). Of the base Et N was
3
the best of choice and as a suitable solvent THF and toluene were effective.
Nevertheless THF was utilized for further studies.
The (E)-adducts 2 were good substrates for the 1,4-elimination to form
tosyl-substrated a,b-unsaturated enones (Table 3). The (E)-adduct 2a
reacted with Et N (1.1 equiv.) in THF for 3 h at rt to afford the enone 3a
3
in 68% yield (Entry 1 in Table 3). For the substrate 2b under the same
conditions enone 3b was provided in 80% yield (Entry 2). The alkyl-
substituted (E)-allylic bromides 2c and 2d were treated under the same
conditions to provide the corresponding 3c and 3d in 78 and 83% yields,
respectively (Entries 3 and 4). The cyclohexyl-substituted adduct 2e was
subjected to base-promoted elimination to give tosyl-substituted enone 3e
in 66% yield (Entry 5). The aryl-substituted (E)-allylic bromides 2f and 2g
were readily converted into enones 3f and 3g in 68 and 84% yields,
respectively (Entries 6 and 7).
In summary, the regioselective radical addition of a-allenic alcohol
with p-TsBr in the presence of AIBN to give (E)-unsaturated g-bromo-b-
sulfonyl allylic alcohols and base-promoted 1,4-elimination of the resulting
allylic bromides to afford b-sulfonyl-a,b-unsaturated ketones were
accomplished.

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b-p-TOSYL-SUBSTITUTED a,b-UNSATURATED KETONES
Table 3. 1,4-Elimination of the Radical Adducts
3267
Radical
Adducts
Unsaturated
Ketones
Isolated
Yield (%)
Entry
1
68
80
78
2
3
4
5
83
66
6
7
68
84
EXPERIMENTAL SECTION
Typical Procedure
Preparation of 1-bromo-2-(toluene-4-sulfonyl)dec-2-en-4-ol (2a): To a
stirred solution of allenic alcohol 1a (50 mg, 0.32 mmol) and AIBN (11 mg,
0.06 mmol) in toluene (3 mL) was added p-TsBr (84 mg, 0.36 mmol)
and heated at 90 C for 2 h. Toluene was evaporated in vacuo and the
ꢀ
crude product was separated by SiO column chromatography (EtOAc/
2
hexanes 1 : 3, R ¼ 0.28) to give 1-bromo-2-(toluene-4-sulfonyl)dec-2-en-4-ol
f

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268
KANG, KO, AND LEE
1
(
1
4
2a) (95 mg, 75%); H NMR (CDCl , 500 MHz) ꢀ 0.88 (t, 3H, J ¼ 6.8 Hz),
3
.29 (m, 7H), 1.43 (m, 1H), 1.66 (m, 2H), 2.30 (d, 1H, J ¼ 4.4 Hz), 2.45 (s, 3H),
.22 (d, 1H, J ¼ 11.4 Hz), 4.26 (d, 1H, J ¼ 11.4 Hz), 4.55 (m, 1H), 7.02 (d, 1H,
1
3
J ¼ 7.9 Hz), 7.35 (d, 2H, J ¼ 8.2 Hz), 7.78 (d, 2H, J ¼ 8.2 Hz); C NMR
(
1
125 MHz, CDCl ) ꢀ 14.7, 21.3, 22.3, 23.2, 25.6, 29.7, 32.3, 36.7, 69.5,
3
ꢁ
1
29.2, 130.6, 137.1, 140.1, 145.6, 147.9; IR (KBr, cm ) 3500, 2929, 2858,
1661, 1630, 1313, 1144, 1085; HRMS (EI) m/z 388.0729 (calcd. for
C H BrO S 388.0708).
1
7
25
3
5
-Bromo-4-(toluene-4-sulfonyl)pent-3-en-2-ol (2b): TLC, SiO , EtOAc/
2
1
hexanes 1 : 3, R ¼ 0.31. H NMR (CDCl , 500 MHz) ꢀ 1.40 (d, 3H,
f
3
J ¼ 7.1 Hz), 2.44 (s, 3H), 2.73 (d, 1H, J ¼ 4.5 Hz), 4.18 (d, 1H, J ¼ 11.6 Hz),
.25 (d, 1H, J ¼ 11.6 Hz), 4.74 (m, 1H), 7.03 (d, 1H, J ¼ 7.9 Hz), 7.35 (d, 2H,
4
1
3
J ¼ 8.2 Hz), 7.78 (d, 2H, J ¼ 8.2 Hz); C NMR (125 MHz, CDCl ) ꢀ 21.2,
3
ꢁ
1
2
2.4, 22.6, 65.6, 129.2, 129.8, 130.7, 139.2, 145.8, 148.8; IR (neat, cm
498, 2977, 2926, 1639, 1595, 1450, 1315, 1187, 1143, 1085; HRMS (EI)
)
3
m/z 317.9913 (calcd. for C H BrO S 317.9925).
1
2
15
3
6
-Bromo-2-methyl-5-(toluene-4-sulfonyl)hex-4-en-3-ol (2c): TLC, SiO ,
2
1
EtOAc/hexanes 1 : 3, R ¼ 0.28. H NMR (CDCl , 500 MHz) ꢀ 0.94 (d, 2H,
f
3
J ¼ 6.8 Hz), 1.01 (d, 2H, J ¼ 6.8 Hz), 1.91 (m, 1H), 2.23 (d, 1H, J ¼ 4.5 Hz),
.45 (s, 3H), 4.26 (d, 1H, J ¼ 11.4 Hz), 4.28 (d, 1H, J ¼ 11.4 Hz), 4.30
m, 1H), 7.05 (d, 1H, J ¼ 8.3 Hz), 7.35 (d, 2H, J ¼ 8.2 Hz), 7.79 (d, 2H,
2
(
1
3
J ¼ 8.2 Hz); C NMR (125 MHz, CDCl ) ꢀ 15.5, 16.0, 18.5, 19.4, 31.6,
3
ꢁ1
7
2
1.0, 126.1, 127.7, 134.1, 137.7, 142.7, 144.0; IR (neat, cm ) 3493, 3013,
918, 2863, 1632, 1596, 1316, 1143, 1084; HRMS (EI) m/z 346.0222 (calcd.
for C H BrO S 346.0238).
1
4
19
3
5
-Bromo-4-(toluene-4-sulfonyl)pent-3-en-2-ol
1
(2d):
TLC,
SiO2,
EtOAc/hexanes 1 : 3, R ¼ 0.31. H NMR (CDCl , 500 MHz) ꢀ 0.87(t, 3H,
f
3
J ¼ 6.7Hz), 1.31 (m, 4H), 1.65 (m, 2H), 2.44 (s, 3H), 3.32 (s, 1H), 4.20 (d, 1H,
J ¼ 11.5 Hz), 4.27(d, 1H, J ¼ 11.5 Hz), 4.52 (m, 1H), 7.02 (d, 1H, J ¼ 7.9 Hz),
1
3
7
.34 (d, 2H, J ¼ 8.2 Hz), 7.78 (d, 2H, J ¼ 8.2 Hz); C NMR (125 MHz,
CDCl ) ꢀ 11.6, 18.4, 19.3, 20.2, 24.8, 33.2, 66.1, 126.1, 127.7, 133.9, 136.3,
3
ꢁ1
1
1
42.7, 145.7; IR (KBr, cm ) 3518, 3056, 2959, 2862, 1634, 1597, 1465, 1267,
143, 1018; HRMS (EI) m/z 360.0379 (calcd. for C H BrO S 360.0395).
1
5
21
3
4
-Bromo-1-cyclohexyl-3-(toluene-4-sulfonyl)but-2-en-1-ol (2e): TLC,
1
SiO , EtOAc/hexanes 1 : 3, R ¼ 0.30. H NMR (CDCl , 500 MHz) ꢀ 1.14
2
f
3
(
m, 6H), 1.60 (m, 4H), 1.90 (m, 1H), 2.44 (s, 3H), 2.78 (d, 1H,
J ¼ 4.7Hz), 4.19 (d, 1H, J ¼ 11.5 Hz), 4.26 (d, 1H, J ¼ 11.5 Hz), 4.28
m, 1H), 7.04 (d, 1H, J ¼ 8.3 Hz), 7.34 (d, 2H, J ¼ 8.2 Hz), 7.77 (d, 2H,
(
1
3
J ¼ 8.2 Hz); C NMR (125 MHz, CDCl ) ꢀ 21.6, 26.5, 27.0, 29.0, 29.4,
3
ꢁ
1
4
3
3
4.2, 73.4, 129.2, 130.7, 137.0, 140.5, 145.7, 147.2; IR (KBr, cm ) 3483,
054, 2930, 2855, 1597, 1449, 1315, 1265, 1145, 1084; HRMS (EI) m/z
86.0534 (calcd. for C H BrO S 386.0551).
1
7
23
3

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b-p-TOSYL-SUBSTITUTED a,b-UNSATURATED KETONES
3269
4
-Bromo-1-phenyl-3-(toluene-4-sulfonyl)but-2-en-1-ol (2f ): TLC, SiO ,
2
1
EtOAc/hexanes 1 : 3, R ¼ 0.25. H NMR (CDCl , 500 MHz) ꢀ 2.44 (s, 3H),
f
3
2
5
7
1
(
1
.52 (d, 1H, J ¼ 4.2 Hz), 4.22 (d, 1H, J ¼ 11.8 Hz), 4.26 (d, 1H, J ¼ 11.8 Hz),
.60 (dd, 1H, J ¼ 7.5, 4.2 Hz), 7.23 (d, 1H, J ¼ 7.5 Hz), 7.32–7.42 (m, 7H),
1
3
.75 (d, 2H, J ¼ 8.2 Hz); C NMR (125 MHz, CDCl ) ꢀ 21.4, 22.4, 71.8,
3
27.3, 129.3, 129.6, 129.8, 130.7, 136.8, 139.9, 140.5, 146.1, 146.2; IR
ꢁ1
KBr, cm ) 3478, 3031, 2921, 1637, 1595, 1492, 1452, 1400, 1309, 1143,
082; HRMS (EI) m/z 380.0005 (calcd. for C H BrO S 380.0082).
1
7
17
3
4
-Bromo-1-thiophen-2-yl-3-(toluene-4-sulfonyl)but-2-en-1-ol (2g): TLC,
1
SiO , EtOAc/hexanes 1 : 2, R ¼ 0.35. H NMR (CDCl , 500 MHz) ꢀ 2.44 (s,
2
f
3
3
H), 2.62 (d, 1H, J ¼ 3.6 Hz), 4.20 (d, 1H, J ¼ 11.3 Hz), 4.30 (d, 1H,
J ¼ 11.3 Hz), 5.87(d, 1H, J ¼ 7.9, 3.6 Hz), 7.00 (dd, 1H, J ¼ 3.8, 1.1 Hz),
7
7
1
.07 (dd, 1H, J ¼ 3.8, 4.6 Hz), 7.25 (dd, 1H, J ¼ 4.6, 1.1 Hz), 7.35 (m, 3H),
1
3
.78 (d, 2H, J ¼ 8.2 Hz); C NMR (125 MHz, CDCl ) ꢀ 20.5, 22.1, 71.3,
3
28.2, 128.4, 129.0, 129.1, 130.4, 130.6, 136.4, 140.5, 142.8, 145.5; IR
ꢁ
1
neat, cm ) 3454, 3102, 2918, 2856, 1652, 1596, 1419, 1323, 1146, 1090;
(
HRMS (EI) m/z 385.9643 (calcd. for C H BrO S 385.9646).
1
5
15
3 2
Typical Procedure
Preparation of 2-(toluene-4-sulfonyl)dec-2-en-4-one (3a): To a stirred
solution of radical adduct 2a (50 mg, 0.13 mmol) in THF (3 mL) was
added Et N (14 mg, 0.14 mmol) at rt for 3 h. The reaction mixture was
3
stirred for room temperature and quenched with saturated NH Cl solution
4
(
dried over anhydrous MgSO and evaporated in vacuo. The crude product
5 mL) and then extracted with ether (3 ꢂ 30 mL). The organic layer was
4
was separated by SiO2 column chromatography (EtOAc/hexanes ¼ 1 : 3,
R ¼ 0.45) to give 2-(toluene-4-sulfonyl)dec-2-en-4-one (3a) (27mg, 68%);
f
1
H NMR (CDCl , 500 MHz) ꢀ 0.89 (t, 3H, J ¼ 6.8 Hz), 1.30 (m, 6H), 1.60
3
(
m, 2H), 2.17(d, 3H, J ¼ 1.2 Hz), 2.45 (s, 3H), 2.60 (t, 2H, J ¼ 7.0 Hz), 7.24
q, 1H, J ¼ 1.2 Hz), 7.36 (d, 2H, J ¼ 8.2 Hz), 7.75 (d, 2H, J ¼ 8.2 Hz);
(
1
3
C NMR (125 MHz, CDCl ) ꢀ 14.0, 14.7, 22.4, 23.2, 29.6, 32.3, 45.8,
3
ꢁ
1
29.4, 130.5, 130.7, 135.2, 145.9, 151.5, 201.3; IR (neat, cm ) 3057, 2930,
1
2
858, 1701, 1621, 1597, 1428, 1312, 1266, 1154; HRMS (EI) m/z 308.1457
(
calcd. for C H O S 308.1446).
17 24 3
4
-(Toluene-4-sulfonyl)pent-3-en-2-one (3b): TLC, SiO , EtOAc/hexanes
2
1
1
(
(
1
: 3 R ¼ 0.50. H NMR (CDCl , 500 MHz) ꢀ 2.18 (d, 3H, J ¼ 1.2 Hz), 2.36
f
3
s, 3H), 2.46 (s, 3H), 7.24 (q, 1H, J ¼ 1.2 Hz), 7.36 (d, 2H, J ¼ 8.2 Hz), 7.75
1
3
d, 2H, J ¼ 8.2 Hz); C NMR (125 MHz, CDCl ) ꢀ 14.0, 22.4, 33.0, 129.4,
3
ꢁ
1
30.5, 130.8, 135.1, 146.0, 151.9, 198.5; IR (neat, cm ) 3062, 2925, 1705,

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270
KANG, KO, AND LEE
1660, 1621, 1360, 1308, 1186, 1019; HRMS (EI) m/z 238.0662 (calcd. for
C H O S 238.0664).
1
2
14
3
4
-(Toluene-4-sulfonyl)pent-3-en-2-one (3c): TLC, SiO , EtOAc/hexanes
2
1
1
(
(
: 3, R ¼ 0.45. H NMR (CDCl , 500 MHz) ꢀ 0.88 (t, 3H, J ¼ 6.8 Hz), 1.29
f
3
m, 7H), 1.43 (m, 1H), 1.66 (m, 2H), 2.30 (d, 1H, J ¼ 4.4 Hz), 2.45 (s, 3H), 4.22
d, 1H, J ¼ 11.4 Hz), 4.26 (d, 1H, J ¼ 11.4 Hz), 4.55 (m, 1H), 7.02 (d, 1H,
1
3
J ¼ 7.9 Hz), 7.35 (d, 2H, J ¼ 8.2 Hz), 7.78 (d, 2H, J ¼ 8.2 Hz); C NMR
(
1
125 MHz, CDCl ) ꢀ 11.0, 15.3, 19.4, 40.1, 126.3, 126.8, 127.8, 132.2, 142.9,
3
ꢁ1
49.7, 197.6; IR (neat, cm ) 3033, 2968, 2845, 1701, 1621, 1596, 1314, 1156,
1
051; HRMS (EI) m/z 266.0973 (calcd. for C H O S 266.0977).
1
4
18
3
4
-(Toluene-4-sulfonyl)pent-3-en-2-one (3d): TLC, SiO , EtOAc/hexanes
2
1
1
(
2
: 3, R ¼ 0.51. H NMR (CDCl , 500 MHz) ꢀ 0.91 (t, 3H, J ¼ 6.8 Hz), 1.33
f
3
qt, 2H, J ¼ 6.8, 6.7Hz), 1.62 (tt, 2H, J ¼ 6.7, 6.9 Hz), 2.18 (d, 3H, J ¼ 0.9 Hz),
.45 (s, 3H), 2.63 (t, 2H, J ¼ 6.9 Hz), 7.25 (q, 1H, J ¼ 0.9 Hz), 7.37 (d, 2H,
1
3
J ¼ 8.2 Hz), 7.76 (d, 2H, J ¼ 8.2 Hz); C NMR (125 MHz, CDCl ) ꢀ 10.9,
3
11.5, 19.3, 19.8, 23.3, 42.4, 126.3, 127.5, 127.8, 132.2, 142.9, 148.5, 198.2;
IR (KBr, cm ) 3055, 2962, 2874, 1701, 1621, 1597, 1315, 1265, 1157, 1055;
ꢁ
1
HRMS (EI) m/z 280.1131 (calcd. for C H O S 280.1133).
1
5
20
3
1
-Cyclohexyl-3-(toluene-4-sulfonyl)but-2-en-1-one (3e): TLC, SiO ,
2
1
EtOAc/hexanes 1 : 3, R ¼ 0.45. H NMR (CDCl , 500 MHz) ꢀ 1.21
f
3
(
3
(
1
2
1
m, 2H), 1.32 (m, 3H), 1.70 (m, 2H), 1.80 (m, 2H), 1.90 (m, 2H), 2.15 (d,
H, J ¼ 1.2 Hz), 2.45 (s, 3H), 2.50 (m, 1H), 7.28 (q, 1H, J ¼ 1.2 Hz), 7.34
1
3
d, 2H, J ¼ 8.2 Hz), 7.75 (d, 2H, J ¼ 8.2 Hz); C NMR (125 MHz, CDCl ) ꢀ
3
4.0, 22.4, 26.0, 26.4, 28.6, 52.8, 129.3, 130.1, 130.8, 135.2, 145.9, 151.7,
ꢁ
1
04.1; IR (KBr, cm ) 3021, 2921, 2840, 1709, 1601, 1588, 1426, 1311,
122, 1038; HRMS (EI) m/z 306.1248 (calcd. for C H O S 306.1290).
1
7
22
3
1
-Phenyl-3-(toluene-4-sulfonyl)but-2-en-1-one (3f ): TLC, SiO2,
1
EtOAc/hexanes 1 : 3, R ¼ 0.42. H NMR (CDCl , 500 MHz) ꢀ 2.18 (d, 3H,
f
3
J ¼ 1.2 Hz), 2.46 (s, 3H), 7.38 (d, 2H, J ¼ 8.2 Hz), 7.51 (dd, 2H, J ¼ 7.5,
.2 Hz), 7.63 (dd, 1H, J ¼ 7.2, 2.3 Hz), 7.81 (d, 2H, J ¼ 8.2 Hz), 7.92 (q, 1H,
7
1
3
J ¼ 1.2 Hz), 7.98 (dd, 2H, J ¼ 7.5, 2.3 Hz); C NMR (125 MHz, CDCl ) ꢀ
3
1
1
1
4.3, 22.4, 129.3, 129.4, 129.7, 129.9, 130.1, 130.8, 134.8, 137.6, 145.9, 152.0,
ꢁ1
91.3; IR (KBr, cm ) 3042, 2936, 2847, 1698, 1620, 1599, 1439, 1315, 1259,
124, 1099; HRMS (EI) m/z 300.0826 (calcd. for C H O S 300.0820).
1
7
17
3
1
-Thiophen-2-yl-3-(toluene-4-sulfonyl)but-2-en-1-one (3g): TLC, SiO ,
2
1
EtOAc/hexanes 1 : 2, R ¼ 0.51. H NMR (CDCl , 500 MHz) ꢀ 1.15 (d,
f
3
6
H, J ¼ 6.7Hz), 2.16 (d, 3H, J ¼ 1.2 Hz), 2.45 (s, 3H), 2.77 (m, 1H), 7.32
q, 1H, J ¼ 1.2 Hz), 7.37 (d, 2H, J ¼ 8.2 Hz), 7.76 (d, 2H, J ¼ 8.2 Hz);
(
1
3
C NMR (125 MHz, CDCl ) ꢀ 14.7, 21.3, 22.3, 23.2, 25.6, 29.7, 32.3,
3
ꢁ
1
3
2
3
6.7, 69.5, 129.2, 130.6, 137.1, 140.1, 145.6, 147.9; IR (neat, cm ) 2961,
925, 2847, 1659, 1649, 1418, 1305, 1241, 1149, 1067; HRMS (EI) m/z
88.0729 (calcd. for C H O S 388.0708).
1
5
14
3

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2002 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc.
b-p-TOSYL-SUBSTITUTED a,b-UNSATURATED KETONES
3271
ACKNOWLEDGMENTS
This paper was supported by Samsung Research Fund,
Sungkyunkwan University, 2000. B.-S. Ko and D.-M. Lee thanks financial
support from BK21 School of Molecular Science.
REFERENCES
1
2
. Review: Bertrand, M.P. Org. Prepn. Proced. Int. 1994, 26, 257, 1–381.
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with p-TsBr and AIBN: Caddick, S.; Shering, C.L.; Wadman, S.N.
Chem. Commun. 1997, 171; (c) Bertrand et al. investigated the photo-
induced radical addition of p-TsBr to the tethered 1,6-Dienes to form
heterocycles: De Riggi, E.; Surzur, J.-M.; Bertrand, M.P. Tetrahedron
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(
e) Nouguier, R.; Lesueur, C.; De Riggi, E.; Bertrand, M.P.; Virgili, A.
Tetrahedron Lett. 1990, 31, 3541; (f ) Wang et al. Reported the chemo-
selective photochemical addition of TsBr to acrylamides and cyclization
to form lactams: Wang, C.; Russel, G.A. J. Org. Chem. 1999, 64, 2346.
. (a) Byrd, L.R.; Caserio, M.C. J. Org. Chem. 1972, 37, 3881;
4
(
2
b) Truce, W.E.; Heuring, D.L.; Wolf, G.C. J. Org. Chem. 1974, 39,
38; (c) Truce, W.E.; Heuring, D.L. J. Org. Chem. 1974, 39, 245.
5
6
7
. Kang, S.-K.; Ko, B.-S.; Ha, Y.-H. J. Org. Chem. 2001, 66, 3630–3633.
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. The (E)-Stereochemistry of 2a and 2f was determined by nOe
1
Experiments in H NMR.
Received in the Netherlands October 20, 2001

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©
2002 Marcel Dekker, Inc. All rights reserved. This material may not be used or reproduced in any form without the express written permission of Marcel Dekker, Inc.