NaOH-promoted thiolysis of oxiranes using 2-[bis(alkylthio)methylene]-3- oxo-N-o-tolylbutanamides as odorless thiol equivalents

Article abstract of DOI:10.1055/s-2006-958438

A convenient and efficient protocol for the thiolysis of oxiranes using 2-[bis(alkylthio)methylene]-3-oxo-N-o-tolylbutanamides as thiol equivalents has been developed. Promoted by sodium hydroxide (NaOH) in ethanol at room temperature, the cleavage commences and the generated thiolate anions undergo nucleophilic addition in situ. β-Hydroxy Sulfides were obtained in high yields along with good β-regioselectivity, and trans β-hydroxy Sulfides were also isolated. The thiolysis of one α,β-epoxyketone product with the thiol equivalents was accomplished to afford the corresponding α-carbonyl sulfides in excellent yields. In all the cases, 3-oxo-N-o-tolylbutanamide, the precursor of the thiol equivalents, could be recovered in the novel thiolysis process as a byproduct in good yield. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2006-958438

LETTER
151
NaOH-Promoted Thiolysis of Oxiranes Using 2-[Bis(alkylthio)methylene]-
3-oxo-N-o-tolylbutanamides as Odorless Thiol Equivalents
N
aOH-Promoted T
a
hiolysis of
i
O
xiran
f
es eng Yu,a,b Dewen Dong,*a Yan Ouyang,a Yan Wang,a Qun Liu*a
a
Department of Chemistry, Northeast Normal University, Changchun 130024, P. R. of China
Fax +86(431)5098635; E-mail: dongdw663@nenu.edu.cn
b
Department of Chemistry, Anshan Normal College, Anshan 114007, P. R. of China
Received 30 September 2006
undesirable side reactions. Additionally, the thiols, in
particular those with low molecular weight, used in the
thiolysis process are odorous, harmful, highly volatile and
flammable, which can create serious environmental and
safety problems. Indeed, some attempts to develop practi-
cally odorless and less volatile substitutes for the odorous
thiols used in various organic reactions have been made.
Accordingly, a range of odorless or faint-smelling thiols
or their equivalents have been prepared by increasing the
alkyl chain length of thiols,10 making sulfides and
thioesters,11,12 introducing trialkylsilyl group onto the
benzene ring of benzyl mercaptan and benzenethiol,13 or
incorporating propane-1,3-dithiol functions within linear
or cross-linked co-polymeric reagents.14 These reagents
have been widely applied in Swern reaction, Corey–Kim
reaction, thioacetalization, thia-Michael addition, and
umpolung chemistry. To the best of our knowledge, there
is only one report dealing with the use of odorless thiol
equivalents in the thiolysis of 1,2-epoxides, in which aryl
disulfides were employed.7g
Abstract: A convenient and efficient protocol for the thiolysis of
oxiranes using 2-[bis(alkylthio)methylene]-3-oxo-N-o-tolylbutan-
amides as thiol equivalents has been developed. Promoted by sodi-
um hydroxide (NaOH) in ethanol at room temperature, the cleavage
commences and the generated thiolate anions undergo nucleophilic
addition in situ. b-Hydroxy sulfides were obtained in high yields
along with good b-regioselectivity, and trans b-hydroxy sulfides
were also isolated. The thiolysis of one a,b-epoxyketone product
with the thiol equivalents was accomplished to afford the corre-
sponding a-carbonyl sulfides in excellent yields. In all the cases, 3-
oxo-N-o-tolylbutanamide, the precursor of the thiol equivalents,
could be recovered in the novel thiolysis process as a byproduct in
good yield.
Key words: a-carbonyl sulfides, epoxides, b-hydroxy sulfides, a-
oxo ketene-S,S-acetals, thiolysis
The b-hydroxy sulfide unit is a common structural com-
ponent in a vast group of natural products along with use-
ful biological and pharmaceutical activities,1 and is a
versatile moiety for the synthesis of allylic alcohols,
benzoxathiepines, benzotiazepines, a-thioketones, a-sub-
stituted a,b-unsaturated enones, b-hydroxy sulfoxides and
naturally occurring compounds such as leukotrienes LTC4
and LTD4.2,3 A general and straightforward access to b-
hydroxy sulfides is via the thiolysis of 1,2-epoxides with
thiols in the presence of a base in a protic solvent.4,5
Recently, other methods have been developed using
promoters and/or catalysts, such as Lewis acids, Brønsted
acids, and ionic liquids to perform these epoxide-ring-
opening reactions.6,7
In our search for the substitutes for the odorous thiols to
contribute to the development of an environmentally-re-
sponsible chemistry, we have found that various types of
ketene-S,S-acetals could be used in thioacetalization and
thia-Michael additions as non-thiolic and odorless thiol
equivalents under acidic conditions.15 Our recent work
has revealed that thia-Michael reactions of a,b-unsaturat-
ed carbonyl compounds could be achieved using 2-
[bis(alkylthio)methylene]-3-oxo-N-o-tolylbutanamides 1
(Figure 1) as thiol equivalents in the presence of NaOH at
room temperature.16 In our ongoing research to expand the
applications of these kinds of thiol equivalents in organic
synthesis, we investigated the thiolysis of 1,2-epoxides 2
with compounds 1 under basic conditions. Herein, we
wish to report our findings.
So far, extensive related work have focused on the inves-
tigation of various catalysts and reaction media that can
result in mild reaction conditions, highly selectivity, and
general tolerance to a wide range of functionalities.4–7 To
minimize the amount of harmful organic solvents used in
the chemical processes, some research groups achieved
the thiolysis of 1,2-epoxides in water,7f,8 ionic liquid7g or
in the absence of solvent (under solvent-free condi-
tions).6d,9 However, many of the thiolysis reactions still
suffer from some disadvantages, such as drastic reaction
conditions, poor regioselectivity, difficult recovery of
expensive catalysts, unsatisfactory yields, or entailing
The substrates 1 were easily prepared from 3-oxo-N-o-
tolylbutanamide 3, carbon disulfide and alkyl halides cat-
alyzed by tetrabutylammonium bromide (TBAB) in the
presence of potassium carbonate in water in excellent
yields according to the reported procedure.17
1
R
Bn
n-Bu
Et
Me
Allyl
O
O
1a
1b
1c
1d
1e
N
H
SYNLETT 2007, No. 1, pp 0151–0155
0
4.
0
1.
2
0
0
7
RS
SR
Advanced online publication: 20.12.2006
DOI: 10.1055/s-2006-958438; Art ID: W20306ST
© Georg Thieme Verlag Stuttgart · New York
Figure 1

152
H. Yu et al.
LETTER
Our previous work has demonstrated that the cleavage of Table 1 Reactions between 2-[Bis(benzylthio)methylene]-3-oxo-
N-o-tolylbutanamide (1a) and 2-Methyloxirane (2a)a
compounds 1 could be realized in the presence of NaOH
in ethanol.16 Thus, the reaction of 2-[bis(benzylthio)meth-
Entry Base
Ratiob
Time
(min)
Yield of 3c Yield of 4ac
ylene]-3-oxo-N-o-tolylbutanamide (1a; 1.0 mmol) with 2-
methyloxirane (2a; 2.0 mmol) in the presence of NaOH
(2.0 mmol) in ethanol (5 mL) was first attempted in the
present work (Table 1, entry 1). After the mixture was
stirred at room temperature for 35 minutes, workup and
column chromatography of the resulting mixture
furnished a colorless liquid which was characterized as 1-
(benzylthio)propan-2-ol (4a; 89% yield), an anti-
Markovnikov-type adduct, on the basis of its elemental
analyses and spectral data. It is widely known that the
thiolysis process of 1,2-epoxides is strongly dependent on
the experimental conditions.6d,7e,8b Under acidic condi-
tions, the reaction favors the nucleophilic attack of thiol
on the more-substituted a-carbon, depending on the sub-
stituents on the oxirane ring, while under basic conditions
the less-substituted b-carbon is more favored. In the
present work, the thiolysis was completely regioselective,
as is usually observed under basic conditions to yield the
terminal sulfide. Interestingly, compound 3 was obtained
as a byproduct from the reaction system in 80% yield,
which was easily isolated from the resulting mixture and
reused for the preparation of compounds 1. It is worth
mentioning that only very faint thiol smell could be per-
ceived during both the reaction and the workup processes,
indicating that the generated thiolate anions quickly
undergo the thiolysis of oxiranes in situ.
(%)
80
80
76
45
79
(%)
1
2
3
4
5
NaOH
2:1
1:1
1:2
1:3
1:1
35
50
89
NaOH
NaOH
NaOH
K2CO3
90
360
360
600
88
47 (44)
91
a Molar ratio of 2a/1a: 2:1.
b Molar ratio of base/1a.
c Isolated yields, and the data in bracket represents the recovered 1a.
Then a range of reactions of 1a and 2a was carried out in
ethanol with varied molar ratio of NaOH/1a to optimize
the conditions (Table 1, entries 2–4). When the molar
ratio of NaOH/1a was decreased from 2:1 to 1:1, the reac-
tion proceeded smoothly to give 4a in a very high yield
(Table 1, entry 2). Further decrease of the ratio, however,
resulted in much lower reaction rate (Table 1, entries 3
and 4). It was observed that the reaction performed in the
presence of a weak base such as potassium carbonate af-
forded 4a, but required much prolonged reaction time for
a complete conversion (Table 1, entry 5). These experi-
ments demonstrate that the character and the feed amount
of the base employed play important roles in the thiolysis.
A 1:1 molar ratio of NaOH/1a was proven to be sufficient
Table 2 Reactions between 2-[Bis(alkylthio)methylene]-3-oxo-N-o-tolylbutanamides 1 and Oxiranes 2
R1
R1
R2
OH
SR
R1
R2
SR
OH
O
O
NaOH/EtOH
r.t.
α
+
O
+
+
3
N
H
β
R2
RS
SR
1
2
4
5
Entry Substrates
Time
(min)
Product 4
Yield of 4
(%)a
Product 5
Yield of 5
(%)a
Yield of 3
(%)a
1
R
2
R1
R2
H
H
H
H
H
H
H
H
1
2
1a
1b
1c
1a
1b
1c
1d
1e
1a
1b
Bn
2a
2a
2a
2b
2b
2b
2b
2b
2c
2c
Me
Me
Me
Ph
Ph
Ph
Ph
Ph
50
55
55
55
55
50
55
50
50
45
4a
4b
4c
4d
4e
4f
90
87
90
71
75
75
73
71
91b
90b
5a
5b
5c
5d
5e
5f
5g
5h
–
0
0
80
83
82
83
81
84
82
85
84
83
n-Bu
Et
3
0
4
Bn
18
17
15
16
16
5
n-Bu
Et
6
7
Me
4g
4h
4i
8
Allyl
Bn
9
(CH2)4
(CH2)4
10
n-Bu
4j
–
a The isolated yields
b trans-b-Hydroxy sulfide.
Synlett 2007, No. 1, 151–155 © Thieme Stuttgart · New York

LETTER
NaOH-Promoted Thiolysis of Oxiranes
153
Table 3 The Thiolysis of Chalcone Oxide 2d with Compounds 1a
and effective for the cleavage of 1a and the subsequent
addition of the generated thiolate anions to 2a, because
while the thiolysis is proceeding, the ring opening of the
1,2-epoxide leads to the formation of an alkoxide ion
which is responsible for further basification of the reac-
tion medium.
O
O
O
β
N
H
α
+
O
RS
SR
1
2d
Employing the identical conditions used for 4a in Table 1
(entry 2), a range of reactions were performed on com-
pounds 1a–e with selected oxiranes 2a–c, and some of the
results are summarized in Table 2.18 It is noted that the
alkyl oxirane 2a reacts with 1b and 1c, under basic condi-
tions, also in a regioselective manner, affording exclu-
sively the ring-opened products 4b and 4c, respectively
(Table 2, entries 2 and 3). This regioselectivity is
probably due to the steric hindrance faced by the nucleo-
phile that attacks on the less-hindered carbon of the
oxirane-ring. In the cases of aryl oxirane 2b, a mixture of
the two regioisomers (ca 4:1) was formed with the anti-
Markovnikov-type adducts 4 as the major products
(Table 2, entries 4–8). These results suggest that the steric
hindrance effect should still be the predominant factor
affecting the regioselectivity. The slightly lower regio-
selectivity in the thiolysis of 2b, compared with that of 2a,
is attributed to the electronic effect from the substituted
aryl groups. Cyclohexene oxide 2c, as a representative of
cycloalkyl epoxides, was investigated under the identical
conditions. The ring opening of 2c with 1a and 1b
smoothly afforded the corresponding b-hydroxy sulfides
4i and 4j in 91% and 90% yields, respectively (Table 2,
entries 9 and 10). The stereochemistry of the product 4i
was found to be trans from the coupling constants of the
ring protons at d = 2.41 (ddd, J = 4.0, 9.5, 11.5 Hz, 1 H)
for SCH and at d = 3.31 (ddd, J = 4.5, 9.5, 9.5 Hz, 1 H) for
O
NaOH
SR
3
+
EtOH
r.t.
6
Entry Substrate R
Time
(min)
Product 6 Yield of 6b Yieldof3b
(%)
94
95
97
96
95
(%)
85
81
84
80
82
1
2
3
4
5
1a
1b
1c
1d
1e
Bn
55
50
55
55
50
6a
6b
6c
6d
6e
n-Bu
Et
Me
Allyl
a Molar ratio of 2d/1 was 2:1, molar ratio of NaOH/1 was 1:1.
b Isolated yields.
In summary, we have described a novel and odorless
thiolysis of oxiranes 2 using 2-[bis(alkylthio)methylene]-
3-oxo-N-o-tolylbutanamides 1 as thiol equivalents. Pro-
moted by NaOH in ethanol at room temperature, the
cleavage of 1 commences and the generated thiolate
anions undergo nucleophilic addition to 2 in situ. In the
cases of alkyl and aryl 1,2-epoxides 2a and 2b, b-hydroxy
sulfides 4a–h were obtained in high yields along with
good b-regioselectivity, while in the case of cyclohexene
oxide 2c, trans b-hydroxy sulfides 4i and 4j were isolated
as a mixture of two diastereoisomers. In contrast, the
thiolysis of a,b-epoxyketone 2d with compounds 1 was
accomplished with complete a-regioselectivity, which
was followed by a retroaldol reaction to afford the corre-
sponding a-carbonyl sulfides 6a–e in excellent yields.
The simple procedure, mild conditions, and high yields
provide a convenient, efficient and odorless thiolysis of
oxiranes.
1
OCH in its H NMR spectrum, and no syn adduct was
observed. Compound 4j showed similar splitting patterns
at d = 2.34 and d = 3.26, respectively. The results reveal
that the thiolysis of cycloalkyl epoxides with 1 is accom-
plished with high stereoselectivity.
We next examined the thiolysis of chalcone oxide 2d
with compounds 1 under the above optimized conditions.
In these cases, as shown in Table 3, a-carbonyl sulfides
6a–e instead of the desired adducts, b-hydroxy sulfides 4,
were isolated in excellent yields. Meanwhile, both com-
pound 3 and benzaldehyde were obtained as byproducts in
good yields. The results reveal that 2d shows a peculiar
behavior in the thiolysis process in comparison to the
oxiranes 2a–c. A similar phenomenon had been observed
in Fringuelli’s recent work on NaOH-catalyzed thiolysis
of a,b-epoxyketones in water.8a Silverman has pointed out
that two b-hydroxy sulfide isomers are interconvertible
under basic conditions, and the interconversion has been
shown to involve a retroaldol–aldol condensation pro-
cess.19 Thus, the thiolysis of 2d involves the nucleophilic
addition of the thiolate ions, generated from the cleavage
of compounds 1 under basic conditions, to the a-position
of chalcone oxide 2d with complete regioselectivity, and
the subsequent retroaldol reaction of the Markovnikov-
type adducts to afford a-carbonyl sulfides 6.
Acknowledgment
Financial support of this research by the National Natural Science
Foundation of China (20572013), the Ministry of Education of
China (105061 and 10412) and the Department of Science and
Technology of Jilin Province (20050392) is greatly acknowledged.
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154
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stirring. The mixture was stirred at r.t. for about 50 min, after
which time the reaction was complete as indicated by TLC.
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10 mL), and extracted with Et2O (3 ꢀ 15 mL). The combined
organic extracts were washed with H2O (3 ꢀ 15 mL), dried
over MgSO4, filtered and concentrated in vacuo. Separation
was carried out by silica gel chromatography using PE–Et2O
(10:1) as eluent to afford product 4a in 90% yield.
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1-(Butylthio)propan-2-ol (4b): colorless liquid. 1H NMR
(500 MHz, CDCl3): d = 0.83–0.86 (m, 3 H), 1.17–1.20 (m, 3
H), 1.31–1.37 (m, 2 H), 1.48–1.51 (m, 2 H), 2.36–2.42 (m, 1
H), 2.45–2.49 (m, 2 H), 2.61–2.65 (m, 1 H), 2.91 (br, 1 H),
3.77 (br, 1 H). 13C NMR (125 MHz, CDCl3): d = 13.5, 21.8
(2 ꢀ C), 31.7, 31.8, 41.5, 65.3. IR (KBr, neat): 3340, 2925,
1734, 1539, 1459, 1284 cm–1. Anal. Calcd for C7H16OS: C,
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Vaccaro, L. Synlett 2003, 2292.
1-(Ethylthio)propan-2-ol (4c): colorless liquid. 1H NMR
(500 MHz, CDCl3): d = 0.80–0.86 (m, 3 H), 1.25–1.28 (m, 3
H), 2.41–2.46 (m, 1 H), 2.54–2.58 (m, 2 H), 2.63 (br, 1 H),
2.73–2.76 (m, 1 H), 3.83–3.85 (m, 1 H). 13C NMR (125
MHz, CDCl3): d = 15.8, 21.7, 31.6, 41.2, 65.4. IR (KBr,
neat): 2955, 2869, 1458, 1247, 1200 cm–1. Anal. Calcd for
C5H12OS: C, 49.96; H, 10.06. Found: C, 49.81; H, 10.14.
2-(Butylthio)-1-phenylethanol (4e): colorless liquid. 1H
NMR (500 MHz, CDCl3): d = 0.91–0.94 (m, 3 H), 1.38–1.45
(m, 2 H), 1.56–1.62 (m, 2 H), 2.53–2.56 (m, 2 H), 2.70–2.74
(m, 1 H), 2.91–2.94 (m, 1 H), 3.10 (br, 1 H), 4.72–4.74 (m,
1 H), 7.28–7.31 (m, 1 H), 7.31–7.39 (m, 4 H). 13C NMR (125
MHz, CDCl3): d = 13.9, 22.2, 31.9, 32.0, 42.3, 71.8, 126.1
(2 ꢀ C), 128.1, 128.8 (2 ꢀ C), 142.8. IR (KBr, neat): 3426,
3029, 2926, 1740, 1456, 1274 cm–1. Anal. Calcd for
C12H18OS: C, 68.52; H, 8.63. Found: C, 68.64; H, 8.72.
(9) (a) Albanese, D.; Landini, D.; Penso, M. Synthesis 1994, 34.
(b) Mojtahedi, M. M.; Ghasemi, M. H.; Abaee, M. S.;
Bolourtchian, M. ARKIVOC 2005, (xv), 68.
Synlett 2007, No. 1, 151–155 © Thieme Stuttgart · New York

LETTER
2-(Butylthio)-2-phenylethanol (5e): colorless liquid. 1H
NaOH-Promoted Thiolysis of Oxiranes
155
C), 134.4, 139.7. IR (KBr, neat): 3388, 3028, 2919, 1711,
1538, 1454, 1230 cm–1. Anal. Calcd for C11H14OS: C, 68.00;
H, 7.26. Found: C, 68.12; H, 7.19.
NMR (500 MHz, CDCl3): d = 0.84–0.87 (m, 3 H), 1.31–1.39
(m, 2 H), 1.48–1.54 (m, 2 H), 2.09 (br, 1 H), 2.42–2.45 (m,
2 H), 3.83–3.87 (m, 2 H), 3.94–3.97 (m, 1 H), 7.26–7.28 (m,
1 H), 7.29–7.38 (m, 4 H). 13C NMR (125 MHz, CDCl3): d =
13.9, 22.2, 31.1, 31.8, 53.2, 65.8, 127.9, 128.2 (2 ꢀ C), 129.0
(2 ꢀ C), 139.1. IR (KBr, neat): 3386, 3028, 2927, 1713,
1538, 1456, 1276 cm–1. Anal. Calcd for C12H18OS: C, 68.52;
H, 8.63. Found: C, 68.67; H, 8.58.
2-(Butylthio)cyclohexanol (4j): colorless liquid. 1H NMR
(500 MHz, CDCl3): d = 0.89 (t, J = 7.5 Hz, 3 H), 1.22–1.29
(m, 3 H), 1.36–1.44 (m, 3 H), 1.51–1.57 (m, 2 H), 1.68–1.73
(m, 2 H), 2.04–2.10 (m, 2 H), 2.31–2.37 (ddd, J = 4.0, 9.5,
12.5 Hz, 1 H), 2.53 (m, 2 H), 3.03 (br, 1 H), 3.25–3.27 (m, 1
H). 13C NMR (125 MHz, CDCl3): d = 13.6, 22.0, 24.4, 26.2,
29.4, 32.3, 32.9, 33.7, 53.4, 72.0. IR (KBr, neat): 3450, 2930,
1449, 1227 cm–1. Anal. Calcd for C10H20OS: C, 63.77; H,
10.70. Found: C, 63.89; H, 10.62.
2-(Ethylthio)-1-phenylethanol (4f): colorless liquid. 1H
NMR (500 MHz, CDCl3): d = 1.25–1.30 (m, 3 H), 2.53–2.58
(m, 2 H), 2.70–2.75 (m, 1 H), 2.90–2.94 (m, 1 H), 4.71–4.73
(m, 1 H), 7.26–7.30 (m, 1 H), 7.31–7.38 (m, 4 H). 13C NMR
(125 MHz, CDCl3): d = 15.1, 26.3, 41.8, 71.9, 126.1 (2 ꢀ C),
128.1, 128.8 (2 ꢀ C), 142.7. IR (KBr, neat): 3424, 3029,
2921, 1720, 1540, 1451, 1265 cm–1. Anal. Calcd for
C10H14OS: C, 65.89; H, 7.74. Found: C, 65.73; H, 7.62.
2-(Ethylthio)-2-phenylethanol (5f ): colorless liquid. 1H
NMR (500 MHz, CDCl3): d = 1.19–1.22 (m, 3 H), 2.04–2.07
(m, 1 H), 2.42–2.49 (m, 2 H), 3.84–3.89 (m, 2 H), 3.97–4.00
(m, 1 H), 7.26–7.28 (m, 1 H), 7.28–7.35 (m, 4 H). 13C NMR
(125 MHz, CDCl3): d = 15.0, 25.4, 52.8, 65.8, 127.9, 128.3
(2 ꢀ C), 129.0 (2 ꢀ C), 140.0. IR (KBr, neat): 3334, 3028,
2924, 1712, 1540, 1453, 1265 cm–1. Anal. Calcd for
C10H14OS: C, 65.89; H, 7.74. Found: C, 65.77; H, 7.81.
2-(Methylthio)-1-phenylethanol (4g): colorless liquid. 1H
NMR (500 MHz, CDCl3): d = 2.13 (s, 3 H), 2.71–2.76 (m, 1
H), 2.86–2.89 (m, 1 H), 3.02 (br, 1 H), 4.76–4.78 (m, 1 H),
7.29–7.31 (m, 1 H), 7.32–7.38 (m, 4 H). 13C NMR (125
MHz, CDCl3): d = 15.4, 44.0, 71.1, 125.7 (2 ꢀ C), 127.8,
128.4 (2 ꢀ C), 142.4. IR (KBr, neat): 3421, 3029, 2915,
1721, 1540, 1449, 1235 cm–1. Anal. Calcd for C9H12OS: C,
64.25; H, 7.19. Found: C, 64.13; H, 7.24.
2-(Benzylthio)-1-phenylethanone (6a): colorless crystal;
mp 68–70 °C. 1H NMR (500 MHz, CDCl3): d = 3.68 (s, 2 H),
3.76 (s, 2 H), 7.25–7.27 (m, 2 H), 7.32–7.48 (m, 3 H), 7.47–
7.49 (m, 2 H), 7.51–7.53 (m, 1 H), 7.93–7.95 (m, 2 H). 13
C
NMR (125 MHz, CDCl3): d = 35.6, 35.8, 127.0, 128.3 (2 ꢀ
C), 128.4 (2 ꢀ C), 128.5 (2 ꢀ C), 129.0 (2 ꢀ C), 133.0, 135.1,
137.0, 194.2. IR (KBr, neat): 3058, 2923, 1672, 1545, 1450,
1200 cm–1. Anal. Calcd for C15H14OS: C, 74.34; H, 5.82.
Found: C, 74.48; H, 5.77.
2-(Butylthio)-1-phenylethanone (6b): colorless liquid. 1H
NMR (500 MHz, CDCl3): d = 0.82–0.92 (m, 3 H), 1.34–1.42
(m, 2 H), 1.54–1.60 (m, 2 H), 2.54–2.57 (m, 2 H), 3.78 (s,
2 H), 7.45–7.48 (m, 2 H), 7.55–7.58 (m, 1 H), 7.95–7.98 (m,
2 H). 13C NMR (125 MHz, CDCl3): d = 12.7, 20.9, 30.0,
31.0, 36.1, 127.6 (2 ꢀ C), 127.8 (2 ꢀ C), 132.3, 134.2, 193.5.
IR (KBr, neat): 3021, 2950, 1739, 1687, 1511, 1461, 1274
cm–1. Anal. Calcd for C12H16OS: C, 69.19; H, 7.74. Found:
C, 69.38; H, 7.67.
2-(Ethylthio)-1-phenylethanone (6c): colorless liquid. 1H
NMR (500 MHz, CDCl3): d = 1.27 (t, J = 7.5 Hz, 3 H), 2.59
(q, J = 7.5 Hz, 2 H), 3.80 (s, 2 H), 7.46–7.49 (m, 2 H), 7.56–
7.59 (m, 1 H), 7.98 (d, 2 H). 13C NMR (125 MHz, CDCl3):
d = 13.1, 25.3, 35.7, 127.3, 127.7 (2 ꢀ C), 127.8 (2 ꢀ C),
132.3, 193.5. IR (KBr, neat): 3061, 2967, 1675, 1450, 1276
cm–1. Anal. Calcd for C10H12OS: C, 66.63; H, 6.71. Found:
C, 66.51; H, 6.65.
2-(Methylthio)-2-phenylethanol (5g): colorless liquid. 1H
NMR (500 MHz, CDCl3): d = 1.99 (s, 3 H), 2.06 (br, 1 H),
3.87–3.90 (m, 3 H), 7.26–7.29 (m, 1 H), 7.30–7.37 (m, 4 H).
13C NMR (125 MHz, CDCl3): d = 13.7, 54.0, 64.8, 127.6,
127.9 (2 ꢀ C), 128.6 (2 ꢀ C), 139.0. IR (KBr, neat): 3358,
3027, 2923, 1722, 1597, 1458, 1269 cm–1. Anal. Calcd for
C9H12OS: C, 64.25; H, 7.19. Found: C, 64.36; H, 7.15.
2-(Allylthio)-1-phenylethanol (4h): colorless liquid. 1H
NMR (500 MHz, CDCl3): d = 2.66–2.71 (m, 1 H), 2.86–2.90
(m, 1 H), 2.94 (br, 1 H), 3.10–3.19 (m, 2 H), 4.72–4.74 (m,
1 H), 5.10–5.15 (m, 2 H), 5.75–5.83 (m, 1 H), 7.28–7.31 (m,
1 H), 7.32–7.37 (m, 4 H). 13C NMR (125 MHz, CDCl3): d =
34.9, 40.2, 72.0, 118.0, 126.1 (2 ꢀ C), 128.1, 128.8 (2 ꢀ C),
134.3, 142.9. IR (KBr, neat): 3425, 3030, 2914, 1715, 1540,
1452, 1228 cm–1. Anal. Calcd for C11H14OS: C, 68.00; H,
7.26. Found: C, 68.21; H, 7.21.
2-(Methylthio)-1-phenylethanone (6d): colorless liquid.
1H NMR (500 MHz, CDCl3): d = 2.13 (s, 3 H), 3.76 (s, 2 H),
7.45–7.48 (m, 2 H), 7.56–7.59 (m, 1 H), 7.95–7.98 (m, 2 H).
13C NMR (125 MHz, CDCl3): d = 14.9, 38.0, 127.7, 127.8,
127.9 (2 ꢀ C), 132.4, 134.1, 193.0. IR (KBr, neat): 3060,
2918, 1672, 1579, 1447, 1278 cm–1. Anal. Calcd for
C9H10OS: C, 65.02; H, 6.06. Found: C, 65.20; H, 6.12.
2-(Allylthio)-1-phenylethanone (6e): colorless liquid. 1H
NMR (500 MHz, CDCl3): d = 3.18 (d, J = 7.5 Hz, 2 H), 3.76
(s, 2 H), 5.15–5.21 (m, 2 H), 5.74–5.80 (m, 1 H), 7.45–7.48
(m, 2 H), 7.55–7.58 (m, 1 H), 7.96 (d, J = 7.5 Hz, 2 H).
13C NMR (125 MHz, CDCl3): d = 34.9, 35.7, 118.8, 128.9,
129.0, 129.1, 129.2, 133.2, 133.6, 134.2, 194.7. IR (KBr,
neat): 3061, 2917, 1676, 1540, 1449, 1275 cm–1. Anal. Calcd
for C11H12OS: C, 68.71; H, 6.29. Found: C, 68.58; H, 6.37.
(19) (a) Silverman, R. B. J. Am. Chem. Soc. 1981, 103, 5939.
(b) Silverman, R. B. J. Org. Chem. 1981, 46, 4789.
2-(Allylthio)-2-phenylethanol (5h): colorless liquid. 1H
NMR (500 MHz, CDCl3): d = 1.94–1.96 (m, 1 H), 2.98–3.02
(m, 1 H), 3.11–3.15 (m, 1 H), 3.85–3.88 (m, 2 H), 3.94–3.97
(m, 1 H), 5.05–5.12 (m, 2 H), 5.75–5.81 (m, 1 H), 7.27–7.29
(m, 1 H), 7.30–7.37 (m, 4 H). 13C NMR (125 MHz, CDCl3):
d = 34.3, 51.6, 65.9, 117.8, 127.9, 128.5 (2 ꢀ C), 129.0 (2 ꢀ
Synlett 2007, No. 1, 151–155 © Thieme Stuttgart · New York

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