Hydrochalcogenation of symmetrical and unsymmetrical buta-1,3-diynes with diaryl dichalcogenides: Facile entry to (Z)-1-(organylchalcogeno)but-1-en-3-yne derivatives

Article abstract of DOI:10.1055/s-0034-1379330

This work describes an efficient and stereoselective method for the hydrothiolation and -selenation of buta-1,3-diyne derivatives using diaryl disulfides or diselenides, respectively. In the presence of rongalite (HOCH₂SO₂Na) and potassium carbonate, buta-1,3-diynes undergo stereoselective addition of the thiolate or selenide anion generated in situ from diaryl disulfides or diselenides to afford the corresponding (Z)-1-sulfanyl- or (Z)-1-selanylalk-1-en-3-yne derivatives, respectively. The reaction of buta-1,3-diynes with diaryl disulfides or diselenides at higher temperature (70 °C) gave a mixture of monothiolation/selenation and bisthiolation/selenation products in moderate to good yields.

Full text of DOI:10.1055/s-0034-1379330

SYNTHESIS
0
0
3
9
-
7
8
8
1
1
4
3
7
-
2
1
0
X
© Georg Thieme Verlag Stuttgart · New York
2015, 47, 395–410
paper
395
C. Venkateswarlu, S. Chandrasekaran
Paper
Synthesis
Hydrochalcogenation of Symmetrical and Unsymmetrical
Buta-1,3-diynes with Diaryl Dichalcogenides: Facile Entry to
(Z)-1-(Organylchalcogeno)but-1-en-3-yne Derivatives
(Z)-1-(Organylchalcogeno)but-1-en-3-yne Derivatives
R1
R2
Cheerladinne Venkateswarlu
Srinivasan Chandrasekaran*
Ar-X-X-Ar
(1 equiv)
Ar-X-X-Ar
(0.5 equiv)
A
+
Department of Organic Chemistry, Indian Institute of Science,
ONa
70 °C HO
S
Bangalore 560 012, Karnataka, India
+
9
1
8
(
0
2
)
3
6
0
0
5
2
9
40/50 °C
scn@orgchem.iisc.ernet.in
O
H
R2
X
H
R2
Ar
Ar
X
Ar
Ar-X-X-Ar (0.5 equiv)
70 °C
R1
X
R1
H
A (Z-isomer)
conditions: K2CO3, DMF–H2O (20:1)
R1, R2 = aryl, alkyl
X = S, Se
Received: 31.07.2014
form C–C bonds by cross-coupling reactions with magne-
sium or zinc reagents3r–t in the presence of a nickel catalyst.
Despite their various applications, the synthesis of alkenyl
chalcogenides has remained a challenge due to the prob-
lems of regio- and stereochemistry. Generally, the hydro-
thiolation of alkynes with thiols proceeds via a free radical
or ionic pathway (acid- or base-catalyzed) or can be metal-
catalyzed depending on the reaction conditions.5
Accepted after revision: 26.09.2014
Published online: 13.11.2014
DOI: 10.1055/s-0034-1379330; Art ID: ss-2014-z0479-op
Abstract This work describes an efficient and stereoselective method
for the hydrothiolation and -selenation of buta-1,3-diyne derivatives us-
ing diaryl disulfides or diselenides, respectively. In the presence of ron-
galite (HOCH2SO2Na) and potassium carbonate, buta-1,3-diynes under-
go stereoselective addition of the thiolate or selenide anion generated
in situ from diaryl disulfides or diselenides to afford the corresponding
(Z)-1-sulfanyl- or (Z)-1-selanylalk-1-en-3-yne derivatives, respectively.
The reaction of buta-1,3-diynes with diaryl disulfides or diselenides at
higher temperature (70 °C) gave a mixture of monothiolation/selena-
tion and bisthiolation/selenation products in moderate to good yields.
Most commonly, vinyl chalcogenides can be synthesized
from acetylenes by the addition of chalcogenide anions in a
nucleophilic pathway. This addition takes place in a trans
manner to form the (Z)-vinylic isomer with high stereose-
lectivity. The formation of nucleophilic species involves the
reaction of chalcogenols with a strong base. There are many
methods available in literature for the synthesis of vinyl
sulfides. However, only a few methods are known for the
synthesis of (Z)-1-(organylsulfanyl)enynes with high regio-
and stereoselectivity.2b,6 Such conjugated (Z)-1-(organylsul-
fanyl- or -selanyl)enynes are used as intermediates for the
synthesis of an enediyne system as well as derivatives of
thiophenes6a,7 and selenophenes.8 This prompted us to scan
the literature methods for the synthesis of these com-
pounds. Baroni et al. achieved the synthesis of (Z)-1-(orga-
nylsulfanyl)enynes by the reaction of symmetrical and un-
symmetrical buta-1,3-diynes with in situ generated sodium
organylthiolate anions under reflux conditions.7 Perin and
co-workers studied this reaction using a solid-catalyst sys-
tem such as potassium fluoride/alumina with thiols in the
presence of solvents like PEG-400 or glycerol.9 Reducing
agents such as sodium borohydride3g,6b,8a,10 were used for
the cleavage of dichalcogenides, which generates chalco-
genide anions in situ, that were then used for hydrochalco-
genation of symmetrical and unsymmetrical buta-1,3-
diynes. Despite the advantages of the above methods, they
Key words hydrochalcogenation, buta-1,3-diynes, aryl dichalco-
genides, rongalite, reductive cleavage
Hydrochalcogenation is the process of incorporating
chalcogen and hydrogen atoms into an organic framework.
In particular, the direct addition of chalcogenols to
alkenes/alkynes has received greater attention recently due
to the formation of products that are useful in the pharma-
ceutical industry and material science.1 In this context, the
thiol-yne reaction (also called alkyne hydrothiolation) is an
organic reaction between a thiol and an alkyne that leads to
the formation of an alkenyl sulfide.1d,2
Vinyl sulfides/selenides are used as important reagents
and intermediates in organic synthesis. In the literature,
various transformations are reported in which vinyl chalco-
genides serve as reagents to access differently functional-
ized molecules.3 For example, vinyl sulfides are generally
converted into the corresponding aldehydes, ketones, or es-
ters.3b,e,4 Also cleavage of the C–S bond with metals furnish-
es the corresponding anionic species which can be easily
trapped with electrophiles.3j,k,m,4 Similarly, vinyl selenides
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396
C. Venkateswarlu, S. Chandrasekaran
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Synthesis
H
R
S
[BnEt3N]2MoS4 (1)
S
+
R
R
S
R
5a,b
3a R = Ph
4a (0.5 equiv)
3b R = CMe2OH
Scheme 1 Hydrothiolation of buta-1,3-diynes 3a,b with diphenyl disulfide (4a) in the presence of 1
have limitations such as the use of toxic, malodorous chal-
Table 1 Screening for Hydrothiolation of Buta-1,3-diynes 3 with the
Reagent 1 (Scheme 1)
cogenols, harsh reaction conditions, and the formation of
diastereomeric mixtures [(E) and (Z)] of (organylchalco-
geno)enynes. Hence there is a need for newer methods to
access these skeletons diastereospecifically. From our labo-
ratory, we have reported that benzyltriethylammonium
tetrathiomolybdate [(BnEt3N)2MoS4, 1] is a versatile re-
agent11 in organic synthesis. The disulfide bond can be
cleaved in situ using 1, and the cleavage products can be
trapped with various electrophiles.11e,12 In light of this, we
envisioned the use of 1 for the hydrochalcogenation of sym-
metrical and unsymmetrical buta-1,3-diynes.
We began our investigation by treating 1,4-diphenylbu-
ta-1,3-diyne (3a, 1 equiv) with diphenyl disulfide (4a, 0.5
equiv) under various conditions in the presence of 1
(Scheme 1). Initially, the reaction between 1,4-diphenylbu-
ta-1,3-diyne (3a) and diphenyl disulfide (4a, 0.5 equiv) was
performed with benzyltriethylammonium tetrathiomolyb-
date (1, 2 equiv) in acetonitrile at room temperature. This
resulted in the formation of only traces of the expected
product, (Z)-sulfanylenyne 5a after 12 hours (Table 1, entry
1).
Heating the reaction mixture to 50 °C and the use of sol-
vents such as toluene, tetrahydrofuran, ethanol, acetoni-
trile–ethanol (1:1) at this temperature did not furnish the
product 5a in reasonable yield (Table 1, entries 2–6). Then
the reaction was performed with more reactive substrate
such as 2,7-dimethylocta-3,5-diyne-2,7-diol6b (3b) in the
presence of 1 in acetonitrile at 50 °C which gave the corre-
sponding (Z)-sulfanylenyne 5b in 33% yield. Considerable
efforts to increase the yield of the reaction with various di-
sulfides under different reaction conditions were unsuc-
cessful.
Entry Diyne
Solvent
Temp
(°C)
Time Product Yielda
(h) (%)
1
2
3
4
5
6
7
8
3a
3a
3a
3a
3a
3a
3b
3b
MeCN
25
50
50
50
50
50
50
50
12
5a
5a
5a
5a
5a
5a
5a
5b
trace
MeCN
12
12
12
12
24
12
12
trace
trace
trace
trace
<5
toluene
THF
MeCN–EtOH (1:1)
EtOH
MeCN
33a
EtOH
35a
a Yield of isolated product.
Then we explored the use of another reducing agent,
sodium hydroxymethanesulfinate (HOCH2SO2Na, 2, also
called rongalite13) which has been studied in our laboratory
for the cleavage of dichalcogenides and further utilized for
ring-opening reactions of aziridines and epoxides.14 Treat-
ment of 1,4-diphenylbuta-1,3-diyne (3a, 1 equiv) and
diphenyl disulfide (4a, 0.5 equiv) in N,N-dimethylform-
amide–water (20:1) with rongalite (2, 3 equiv) followed by
the addition of potassium carbonate (2 equiv) at room tem-
perature furnished [(Z)-4-phenyl-1-(phenylsulfanyl)but-1-
en-3-ynyl]benzene (5a) in 35% yield after eight hours. In or-
der to increase the yield of the reaction, we further raised
the temperature of the reaction to 40 °C15 which gave 5a in
72% yield within three hours (Scheme 2).
ONa
HO
S
O
H
(2)
(3 equiv)
Ph
S
Ph
Ph
+
S
Ph
S
K2CO3 (2 equiv)
DMF–H2O (20:1)
40 °C, 3 h
3a
4a (0.5 equiv)
(Z)-5a 72%
Scheme 2 Hydrothiolation of 1,4-diphenylbuta-1,3-diyne (3a) with diphenyl disulfide (4a) using rongalite (2)
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Synthesis
A mechanism has been proposed previously for the re-
duction of disulfide 4a followed by the hydrothiolation of
1,4-diphenylbuta-1,3-diyne (3a) (Scheme 3).6b,14,16 Initially,
rongalite (2) undergoes decomposition to form formalde-
hyde and HSO2– in the presence of base followed by a single
electron transfer to the disulfide to furnish the intermedi-
ates such as anionic species E and radical F.14,16 The thiolate
radical F further gets reduced to anionic species E, by an-
symmetrical and unsymmetrical buta-1,3-diynes 3b–g
with different disulfides 4a–g under similar reaction condi-
tions (Scheme 4).
The results of this investigation are summarized in Table
2. It can be observed from Table 2 that the symmetrical
buta-1,3-diynes containing hydroxy groups such as 2,7-di-
methylocta-3,5-diyne-2,7-diol (3b) and hexa-2,4-diyne-
1,6-diol (3c) upon reaction with diphenyl disulfide (4a) in
the presence of rongalite (2) for three hours give the corre-
sponding (Z)-sulfanylenynes 5b and 5c in 82% and 83%
yields, respectively (entries 1 and 2) whereas aliphatic 1,3-
diyne such as hexadeca-7,9-diyne (3d) furnish only traces
of the desired product 5d even after 12 hours (entry 3).
•
other single electron transfer (SET) from the radical (HSO2 ).
This thiolate E undergoes trans addition to alkyne 3a
generating an intermediate G that on protonation gives the
desired (Z)-sulfanylenyne derivative 5a.6b This result en-
couraged us to study the scope of the reaction using various
ONa
K2CO3
HO
S
HSO2–Na+
+
HCHO
O
2
•
– HSO2
S
•
S–
HSO2–Na+
+
S
+
S
4a
E
F
•
•
S–
+
H+
HSO2
+
+
SO2
S
F
E
Ph
S
H
Ph
S
–
H2O
S–
Ph
Ph
+
Ph
Ph
E
G
3a
(Z)-5a
Scheme 3 Mechanism for the hydrothiolation reaction
ONa
HO
S
O
2
H
R2
(3 equiv)
R1
R2
S
R3
+
R3
S
K2CO3 (2 equiv)
DMF–H2O (20:1)
40 °C
R1
Z-isomer
S
3
4
R3
Scheme 4 Hydrothiolation of symmetrical and unsymmetrical buta-1,3-diynes 3 with various disulfides 4
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2015, 47, 395–410

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C. Venkateswarlu, S. Chandrasekaran
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Synthesis
Table 2 Regio- and Stereoselective Synthesis of (Z)-Sulfanylenynes (Scheme 4)
R1
R2
Entry
R3SSR3
Product
Time (h)
Yielda (%)
OH
H
HO
HO
OH
S
1
3b
4a (PhS)2
5b
3
82
HO
HO
H
2
3
4
3c
3d
3e
4a
4a
4a
5c
5d
5e
3
83
S
OH
HO
H
C6H13
S
C6H13
C6H13
12
trace
C6H13
OH
H
3
76
Ph
OH
S
Ph
HO
H
C6H13
5
6
7
3f
4a
5f
3
8
3
73
45
88
S
OH
C6H13
H
C6H13
3g
3c
C6H13
Ph
4a
5g
5h
S
Ph
HO
H
4b (4-MeC6H4S)2
S
HO
OH
H
8
9
3b
4c (4-MeOC6H4S)2 5i
3
3
85
75
S
OMe
HO
H
OH
3f
4c
5j
S
OMe
C6H13
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C. Venkateswarlu, S. Chandrasekaran
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Synthesis
R1
R2
Entry
R3SSR3
Product
Time (h)
Yielda (%)
OH
H
10
11
3b
4d (4-ClC6H4S)2
5k
4
76
65
S
Cl
HO
HO
H
3f
4d
5l
4
S
Cl
C6H13
H
Ph
S
12
13
3a
3a
4e (4-O2NC6H4S)2 5m
8
5
52
63
NO2
Ph
Ph
H
Ph
S
4f (2-pyridylS)2
5n
5o
N
OH
H
H
14
3e
4f
4
73
S
N
Ph
Ph
Ph
S
15
3a
4g (BnS)2
5p
12
–
a Yield of isolated product.
When the unsymmetrical buta-1,3-diynes 3e–g were
used, the reactions were completed in 3–8 hours and (Z)-
sulfanylenynes 5e–g were obtained in moderate to good
yields with high chemoselectivity (Table 2, entries 4–6).
The scope of the reaction was further demonstrated using
other disulfides 4b–g and it was found that aromatic disul-
fides bearing electron-releasing groups on the phenyl ring
such as methyl or methoxy furnished the products in high-
er yields (entries 7–9) compared to disulfides bearing elec-
tron-withdrawing groups like chloro or nitro on the phenyl
moiety (entries 10–12). The heteroaryl disulfide 4f also re-
acted reasonably well with symmetrical and unsymmetri-
cal buta-1,3-diynes under these conditions (entries 13 and
14).17 However, alkyl disulfide such as dibenzyl disulfide
(4g) failed to react with buta-1,3-diyne 3a even after 12
hours (entry 15).
The reason for the reduced reactivity of the aliphatic
symmetrical diacetylene hexadeca-7,9-diyne (3d) com-
pared to other diacetylenes towards the benzenethiolate
anion can be explained by close inspection of the mecha-
nism of the reaction.6b Attack of the benzenethiolate anion
on the diacetylene moiety develops a negative charge at the
adjacent carbon (C2) and the possible transition states6b are
shown in Figure 1. In case of 3a, the incipient carbanion is
stabilized by phenyl-substituted acetylenic group, which
draws electrons efficiently (electronic factor) compared to
transition state A of compound 3d where the octynyl-
substituted acetylene group is involved (Figure 1, A, B).
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C. Venkateswarlu, S. Chandrasekaran
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Synthesis
C6H13 (CH2OH)
Ph (CMe2OH)
C6H13
Ph
δ−
δ−
PhS
PhS
δ−
C6H13
δ−
PhS
PhS
Ph
δ−
H
δ−
δ−
δ−
H
H
OH
H
OH
O
O
A (3d)
B (3a)
C (3b or 3e)
D (3c or 3f)
unstabilzed
stabilized
Figure 1 Possible transition states involved in the hydrothiolation reactions
This possibly explains the low reactivity of compound
3d. The high reactivity of (hydroxymethyl)acetylene triple
bonds over other diacetylenes bearing phenyl or alkyl sub-
stituents can be explained by the ease of formation of cyclic
five-membered transition states6b C and D between the in-
cipient carbanion at C2 and intramolecular hydrogen bond-
ing (Figure 1, C, D). Additionally, steric as well as electronic
factors play a vital role for these propargylic triple bonds
(3b,c,e,f) in determining their reactivity (Table 2, entries 1,
2, 4, and 5).
The reaction resulted in the formation of the corre-
sponding (Z)-selenylenyne 5q in 67% yield after four hours
(Scheme 5).15 The scope of the methodology was further
extended to other buta-1,3-diynes (Scheme 6).
The results are presented in Table 3. Buta-1,3-diynes 3b
and 3c bearing hydroxymethyl groups on both ends reacted
with diselenide 4h (4 h) in the presence of 2 to give the cor-
responding (Z)-selanylenynes 5r and 5s, respectively (en-
tries 1 and 2). Aliphatic diacetylene such as hexadeca-7,9-
diyne (3d) failed to react with diphenyl diselenide even af-
ter 12 hours (entry 3) whereas unsymmetrical buta-1,3-
diynes 3e–g gave the corresponding products 5u–w in
moderate to good yields (entries 4–6).
Like the aryl disulfides, aryl diselenides are also cleaved
in the presence of rongalite (2).14 Accordingly, diphenyl
diselenide (4h) was treated with diacetylene 3a in the pres-
ence of rongalite (2) and potassium carbonate at 50 °C.18
H
Ph
2, K2CO3
Se
Ph
Ph
+
Ph
Se
Se
DMF–H2O (20:1)
50 °C, 4 h
3a
4h (0.5 equiv)
(Z)-5q 67%
Scheme 5 Hydroselenation of 3a with diphenyl diselenide (4h) mediated by rongalite (2)
H
R2
2, K2CO3
Se
R1
R2
+
R1
Se
Se
DMF–H2O (20:1)
50 °C
3
4h (0.5 equiv)
Z-isomer
Scheme 6 Hydroselenation of symmetrical and unsymmetrical buta-1,3-diynes with diphenyl diselenide (4h) mediated by rongalite (2)
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2015, 47, 395–410

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C. Venkateswarlu, S. Chandrasekaran
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Table 3 Synthesis of (Z)-Selanylenynes from Various Buta-1,3-diynes (Scheme 6)
R1
R2
Entry
Product
Time (h)
Yielda (%)
OH
H
1
3b
HO
HO
OH
5r
Se
4
72
HO
HO
H
2
3
4
3c
3d
3e
5s
5t
5u
4
75
Se
OH
HO
H
C6H13
Se
12
–
C6H13
C6H13
C6H13
OH
H
5
68
Ph
OH
Se
Ph
HO
H
C6H13
5
6
3f
5v
7
8
62
42
Se
OH
C6H13
H
C6H13
Se
3g
C6H13
Ph
5w
Ph
a Yield of isolated product.
We then studied the reactivity of 1,4-diorganylbuta-
1,3-diynes using one equivalent of diaryl dichalcogenide at
70 °C with excess rongalite (2) and potassium carbonate.
Accordingly, the reaction was performed with 1,4-diphen-
ylbuta-1,3-diyne (3a) and disulfide 4a (1 equiv) in the pres-
ence of rongalite (2, 5 equiv) and potassium carbonate (3
equiv). Surprisingly, we found a mixture of mono- and bis-
thiolation products 5a and 6a (Scheme 7). This prompted us
to search the literature for methods for the bischalcogena-
tion of alkynes. Very few methods are reported such as the
reaction of 1,4-diorganylbuta-1,3-diynes with thiols in the
presence of strong bases19 or alumina 20 under reflux condi-
tions and metal-catalyzed (Pt or Ni)21 dimerization–bisthio-
lation of alkynes.
To study the scope of the reaction, the methodology was
then extended to other buta-1,3-diynes using various disul-
fides and diselenides. The ratios of mono- and bischalco-
genation products are presented in Table 4. It was found
that butadiynes bearing hydroxymethyl groups on both
ends reacted efficiently with diaryl disulfides to form only
bisthiolation product (entries 1, 2, 4, and 5). For example,
(3Z,5Z)-2,7-dimethyl-3,6-bis(phenylsulfanyl)octa-3,5-diene-
2,7-diol (6b) was obtained as the sole product when buta-
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C. Venkateswarlu, S. Chandrasekaran
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Synthesis
2 (5 equiv)
K2CO3 (3 equiv)
DMF–H2O (20:1)
H
Ph
S
H
Ph
S
Ph
S
S
Ph
Ph
Ph
Ph
+
+
Ph
S
Ph
70 °C, 24 h
78%
Ph
H
3a
4a (1 equiv)
Ph
6a
(Z)-5a
mono/bis = 35:65
Scheme 7 Hydrothiolation of 3a with diphenyl disulfide (4a) at 70 °C in the presence of rongalite (2)
1,3-diyne 3b was reacted with disulfide 4a for 12 hours un-
der the reaction conditions described in Scheme 7 (entry 1).
The unsymmetrical buta-1,3-diyne 3e upon reaction with
diphenyl disulfide (4a) gave a mixture of mono- and bisthi-
olation products (24 h, 78%) in the ratio 32:68 (entry 3).
The reaction of diphenyl diselenide (4h) with diyne 3a fur-
nished the mono- and bisselenation products 5q and 6g in
the ratio 48:52 after 24 hours (entry 6). Also the more reac-
tive buta-1,3-diynes such as 3b and 3c on reaction with 4h
(24 h) resulted in a mixture of mono- and bisselenation
products (entries 7 and 8).
Table 4 Synthesis of Mono- and Bischalcogenation Products from Buta-1,3-diynes 3 and Dichalcogenides 4 (Scheme 7)
Ratioa
mono/bis
R1
R2
Entry
R3SSR3
Product(s)
Time (h) Yieldb (%)
OH
H
PhS
1
3b
HO
HO
OH 4a (PhS)2
6b
6c
0:100
0:100
12
10
82
85
SPh
H
HO
HO
H
PhS
2
3
4
3c
4a
SPh
OH
H
OH
H
OH
5e
6d
SPh
Ph
3e
4a
32:68
24
78
Ph
OH
+
OH
H
PhS
Ph
SPh
H
HO
H
4-MeC6H4S
4b
(4-MeC6H4S)2
3c
6e
0:100
10
86
SC6H4-4-Me
H
OH
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Synthesis
Ratioa
mono/bis
R1
R2
Entry
R3SSR3
Product(s)
Time (h) Yieldb (%)
OH
H
4-ClC6H4S
4d
5
3b
6f
0:100
16
76
(4-ClC6H4S)2
SC6H4-4-Cl
H
HO
H
Ph
SePh
5q
6g
Ph
6
3a
4h (PhSe)2
48:52
24
52
+
H
Ph
PhSe
Ph
SePh
OH
H
H
5r
SePh
HO
7
3b
4h
40:60
24
62
+
OH
H
PhSe
6h
SePh
H
HO
H
HO
5s
SePh
OH
8
3c
4h
34:66
24
66
+
HO
H
PhSe
6i
SePh
H
OH
a Ratio was determined from the yields of the isolated products.
b Total yield of isolated product(s).
The structure of 6g from the bisselenation of 3a was un-
ambiguously determined by X-ray crystallographic analysis
(Figure 2).
Then we decided to extend the methodology to the syn-
thesis of mixed hydrochalcogenation products. In this re-
gard, previously synthesized (Z)-(chalcogeno)enynes were
treated with different dichalcogenides (Scheme 8) and the
results are described in Table 5. Treatment of (Z)-sulfanyl-
enyne 5c (1 equiv) and 4-chlorophenyl disulfide (4d, 0.5
equiv) with rongalite (2, 3 equiv) and potassium carbonate
(2 equiv) at 70 °C for 10 hours afforded the corresponding
product 6j in 80% yield whereas (Z)-sulfanylenyne 5h under
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2015, 47, 395–410

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C. Venkateswarlu, S. Chandrasekaran
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Synthesis
as with diphenyl diselenide (4h), a set of reactions were
performed separately and it was found that hydrothiolation
of 5b with 4a proceeded smoothly in six hours to form the
corresponding product 6b (entry 3) whereas its hydro-
selenation with 4h gave the desired product 6l in only 52%
yield after 24 hours (entry 4).
H
R
H
R
2 (3 equiv)
Ar2Y
R
+ Ar2–Y–Y–Ar2
XAr1
XAr1
K2CO3 (2 equiv)
DMF–H2O (20:1)
70 °C
4 (0.5 equiv)
H
Figure 2 ORTEP of 6g drawn with 50% ellipsoidal probability
R
5
6
X, Y = S, Se
similar conditions furnished mixed hydrothiolation prod-
uct 6k in 82% yield (entries 1 and 2). To study the reactivity
of (Z)-sulfanylenyne 5b with diphenyl disulfide (4a) as well
Scheme 8 Hydrochalcogenation of (Z)-(chalcogeno)enynes
Table 5 Synthesis of Mixed Chalcogenation Products by Hydrochalcogenation Reaction (Scheme 8)
Entry
(Z)-(Chalcogeno)enyne
HO
Ar2YYAr2
Product
Time (h)
10
Yielda (%)
HO
HO
H
H
H
H
4-ClC6H4S
1
5c
4d (4-ClC6H4S)2
6j
80
SPh
SPh
H
H
OH
HO
HO
HO
4-ClC6H4S
2
3
4
5
5h
4d
6k
6b
6l
10
82
85
52
50
SC6H4-4-Me
OH
SC6H4-4-Me
OH
OH
H
H
PhS
5b
5b
5r
4a (PhS)2
4h (PhSe)2
4a
6
SPh
SPh
H
HO
HO
OH
H
PhSe
HO
24
24
SPh
H
OH
OH
H
H
PhS
HO
6l
SePh
SePh
H
HO
a Yield of isolated product.
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C. Venkateswarlu, S. Chandrasekaran
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This indicated that the in situ generated benzenethio-
late anion reacted more efficiently than the benzeneseleno-
late anion. This may be due to the rapid oxidative dimeriza-
tion of selenols and also steric factors involved during hy-
droselenation. Then we studied the reactivity of
structurally similar (Z)-selanylenyne 5r with diphenyl di-
sulfide (4a). When (Z)-selanylenyne 5r was treated with 4a
in the presence of 2 under similar reaction conditions, it
gave the mixed selanyl sulfide 6l in 50% yield after 24 hours
(entry 5). This demonstrates that the structurally similar
(Z)-sulfanylenynes are more reactive than the correspond-
ing (Z)-selanylenynes for this addition reaction.
13C NMR (100 MHz, CDCl3): δ = 147.1, 138.3, 134.4, 131.5, 130.3,
128.6, 128.3, 128.2, 127.9, 126.3, 123.3, 112.2, 98.3, 87.6.
(3Z)-2,7-Dimethyl-3-(phenylsulfanyl)oct-3-en-5-yne-2,7-diol
(5b)6b
White solid; yield: 113.3 mg (82%); mp 103–104 °C.
FTIR (KBr): 3283 (s), 2981 (m), 1580 (w), 1479 (w), 1363 (m), 1211
(m), 1164 (s), 1144 (m), 951 (m), 741 cm–1 (m).
1H NMR (400 MHz, CDCl3): δ = 7.32–7.25 (m, 4 H), 7.15 (t, J = 7.2 Hz, 1
H), 6.44 (s, 1 H), 2.83 (br s, 1 H), 2.24 (br s, 1 H), 1.48 (s, 6 H), 1.23 (s, 6
H).
13C NMR (100 MHz, CDCl3): δ = 153.0, 135.9, 128.7, 128.0, 125.6,
113.2, 103.8, 79.2, 74.6, 65.2, 30.5, 28.8.
In summary, we have developed an ecofriendly and
metal-free method for the hydrochalcogenation of 1,4-dior-
ganylbuta-1,3-diynes using rongalite as a reducing agent
The significance of the method are high regio- and stereo-
selectivity, avoiding the use of toxic and malodorous chal-
cogenols, and an easy workup procedure. The scope of this
method was also elaborated for the synthesis of bischalco-
genation products under metal-free conditions at higher
temperatures. Studies aimed at exploring the synthetic util-
ity of these compounds are in progress.
(2Z)-2-(Phenylsulfanyl)hex-2-en-4-yne-1,6-diol (5c)9
White solid; yield: 91.4 mg (83%); mp 110–112 °C.
FTIR (KBr): 3402 (s), 2921 (w), 1637 (w), 1020 (s), 1004 (s), 752 cm–1
(m).
1H NMR (400 MHz, CD3COCD3): δ = 7.45–7.43 (m, 2 H), 7.40–7.31 (m,
3 H), 6.16 (pent, J = 2.4, 1.6 Hz, 1 H), 4.44 (t, J = 5.6 Hz, 1 H), 4.35–4.34
(m, 2 H), 4.30–4.26 (m, 1 H), 4.01 (d, J = 5.6 Hz, 2 H).
13C NMR (100 MHz, CD3COCD3): δ = 147.6, 132.5, 132.2, 129.3, 128.0,
108.0, 96.4, 80.7, 63.6, 50.5.
(3Z)-2-Methyl-6-phenyl-3-(phenylsulfanyl)hex-3-en-5-yn-2-ol
(5e)9
All reactions were performed in oven dried apparatus and were
stirred magnetically. IR spectra were recorded using a Jasco FT-IR in-
strument. 1H and 13C NMR spectra were recorded on 400 MHz (100
White solid; yield: 111.7 mg (76%); mp 60–62 °C.
FTIR (KBr): 3441 (s), 2972 (m), 2199 (w), 1579 (w), 1440 (w), 1362
1
MHz, 13C) NMR spectrometer and calibrated using TMS (for H NMR)
(m), 1210 (m), 1179 (s), 976 (m), 834 (m), 757 (s), 741 (m), 687 cm–1
(s).
or residual undeuterated solvent (for 1H and 13C) as an internal refer-
ence. Mass spectra were recorded on a Q-TOF electrospray instru-
ment. Melting point values reported are uncorrected. Commercial
grade solvents were distilled prior to use. All buta-1,3-diyne deriva-
tives were synthesized using reported protocols22 and disulfides and
diphenyl diselenide were purchased commercially. Spectral data of
products obtained were consistent with the reported com-
pounds.6b,7,9,21
1H NMR (400 MHz, CDCl3): δ = 7.38 (d, J = 7.7 Hz, 2 H), 7.27–7.06 (m, 8
H), 6.63 (s, 1 H), 2.25 (br s, 1 H), 1.52 (s, 6 H).
13C NMR (100 MHz, CDCl3): δ = 153.2, 135.4, 131.4, 128.8, 128.6,
128.3, 128.0, 125.9, 122.9, 114.2, 98.9, 86.6, 74.7, 29.1.
(2Z)-2-(Phenylsulfanyl)undec-2-en-4-yn-1-ol (5f)6b
Yellow oily liquid; yield: 100.2 mg (73%).
(Z)-1-Sulfanyl or -selanylalk-1-en-3-ynes 5; General Procedure
FTIR (neat): 3370 (m), 2955 (m), 2931 (s), 2858 (m), 2215 (w), 1583
(w), 1477 (w), 1100 (m), 1023 (m), 746 (m), 692 cm–1 (w).
1H NMR (400 MHz, CDCl3): δ = 7.42 (d, J = 7.4 Hz, 2 H), 7.30–7.23 (m, 3
H), 6.01 (s, 1 H), 4.01 (d, J = 4.2 Hz, 2 H), 2.37–2.33 (m, 3 H), 1.56–1.26
(m, 8 H), 0.87 (t, J = 7.0 Hz, 3 H).
13C NMR (100 MHz, CDCl3): δ = 144.7, 132.2, 132.0, 128.9, 127.6,
110.8, 99.1, 76.9, 64.4, 31.2, 28.5, 28.4, 22.4, 19.7, 13.9.
To a well-stirred solution of 1,4-diorganylbuta-1,3-diyne (0.5 mmol, 1
equiv) in DMF–H2O (20:1; 4 mL), the disulfide/diselenide (0.25 mmol,
0.5 equiv) was added followed by the addition of rongalite 2 (1.5
mmol, 3 equiv) and K2CO3 (1 mmol, 2 equiv). The mixture was stirred
at 40 °C or 50 °C for the time indicated in Table 2 or 3. Completion of
the reaction was monitored by TLC until consumption of the starting
material. The mixture was allowed to attain r.t. and water was added
followed by extraction with EtOAc (2 × 20 mL). The organic layer was
separated, then washed with brine, extracted with EtOAc (2 × 5 mL),
and dried (anhyd Na2SO4). The solvent was evaporated under vacuum
and the crude product was purified by column chromatography (sili-
ca gel, 230–400 mesh, EtOAc–petroleum ether).
[(3Z)-4-(Phenylsulfanyl)dec-3-en-1-ynyl]benzene (5g)23
Yellow liquid; yield: 72.1 mg (45%).
FTIR (neat): 3424 (s), 2954 (m), 2927 (s), 2855 (m), 1599 (m), 1440
(m), 1021 (m), 754 (m), 690 cm–1 (m).
1H NMR (400 MHz, CDCl3): δ = 7.47–7.23 (m, 10 H), 5.84 (s, 1 H), 2.18
(t, J = 7.4 Hz, 2 H), 1.44–1.14 (m, 8 H), 0.83 (t, J = 7.0 Hz, 3 H).
[(1Z)-4-Phenyl-1-(phenylsulfanyl)but-1-en-3-ynyl]benzene (5a)6b
White solid; yield: 112.5 mg (72%); mp 93–95 °C.
13C NMR (100 MHz, CDCl3): δ = 150.7, 133.2, 132.6, 131.4, 128.9,
128.2, 127.9, 127.7, 123.5, 107.3, 95.9, 86.7, 36.1, 31.4, 28.5, 28.4,
22.4, 14.0.
FTIR (neat): 3368 (br s), 1582 (s), 1478 (m), 1440 (m), 1018 (s), 754
(s), 738 (s), 688 cm–1 (s).
1H NMR (400 MHz, CDCl3): δ = 7.52–7.02 (m, 15 H), 6.32 (s, 1 H).
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Synthesis
(2Z)-2-[4-(Methylphenyl)sulfanyl]hex-2-en-4-yne-1,6-diol (5h)
1H NMR (400 MHz, CDCl3): δ = 7.35 (d, J = 8.3 Hz, 2 H), 7.27 (d, J = 8.3
Hz, 2 H), 6.06 (s, 1 H), 4.05 (s, 2 H), 2.35 (t, J = 6.9 Hz, 2 H), 1.55–1.26
(m, 9 H), 0.88 (t, J = 6.3 Hz, 3 H).
13C NMR (100 MHz, CDCl3): δ = 144.0, 133.6, 133.2, 130.9, 129.1,
112.0, 99.6, 76.8, 64.5, 31.2, 28.5, 28.4, 22.5, 19.7, 14.0.
Pale pink solid; yield: 103.1 mg (88%); mp 87–89 °C.
FTIR (neat): 3328 (s), 2924 (w), 2204 (w), 1339 (w), 1016 (s), 1004 (s),
973 (m), 814 cm–1 (m).
1H NMR (400 MHz, CDCl3): δ = 7.33 (d, J = 8.0 Hz, 2 H), 7.11 (d, J = 7.9
Hz, 2 H), 5.98 (s, 1 H), 4.38 (s, 2 H), 3.98 (s, 2 H), 3.19 (br s, 2 H), 2.32
(s, 3 H).
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C17H21ClOSNa: 331.0899;
found: 331.0901.
13C NMR (100 MHz, CDCl3): δ = 148.1, 138.4, 133.3, 129.8, 127.1,
106.8, 95.2, 81.8, 64.0, 51.3, 21.0.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C13H14O2SNa: 257.0612;
found: 257.0612.
1-{[(1Z)-1,4-Diphenylbut-1-en-3-ynyl]sulfanyl}-4-nitrobenzene
(5m)
Pale yellow solid; yield: 92.9 mg (52%); mp 169–171 °C.
FTIR (KBr): 3423 (s), 2926 (w), 2066 (w), 1641 (w), 1019 cm–1 (m).
(3Z)-3-[(4-Methoxyphenyl)sulfanyl]-2,7-dimethyloct-3-en-5-yne-
1H NMR (400 MHz, CDCl3): δ = 7.99 (d, J = 8.8 Hz, 2 H), 7.60–7.58 (m, 2
2,7-diol (5i)
H), 7.43–7.29 (m, 10 H), 6.59 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 145.6, 145.0, 143.2, 137.5, 131.6,
129.3, 128.85, 128.78, 128.5, 128.4, 127.5, 123.8, 122.7, 116.0, 99.8,
87.0.
Yellow gummy mass; yield: 130.1 mg (85%).
FTIR (neat): 3426 (s), 2978 (s), 2932 (s), 1721 (m), 1594 (m), 1494 (s),
1463 (s), 1287 (m), 1246 (s), 1174 (m), 1032 (m), 947 (m), 825 cm–1
(m).
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C22H15NO2SNa: 380.0721;
1H NMR (400 MHz, CDCl3): δ = 7.32 (d, J = 8.6 Hz, 2 H), 6.84 (d, J = 8.6
Hz, 2 H), 6.32 (s, 1 H), 3.78 (s, 3 H), 2.31 (br s, 2 H), 1.48 (s, 6 H), 1.32
(s, 6 H).
found: 380.0726.
2-{[(1Z)-1,4-Diphenylbut-1-en-3-ynyl]sulfanyl}pyridine (5n)
13C NMR (100 MHz, CDCl3): δ = 158.4, 154.9, 131.2, 126.5, 114.4,
White solid; yield: 98.7 mg (63%); mp 77–79 °C.
111.7, 103.4, 79.2, 74.5, 65.3, 55.4, 30.8, 29.0.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C17H22O3SNa: 329.1187;
FTIR (KBr): 3053 (w), 2188 (w), 1573 (m), 1558 (m), 1445 (m), 1424
(m), 1135 (w), 760 (s), 690 cm–1 (m).
1H NMR (400 MHz, CDCl3): δ = 8.36 (d, J = 3.9 Hz, 1 H), 7.65 (dd, J = 2.0,
7.7 Hz, 2 H), 7.43–7.25 (m, 9 H), 7.02 (d, J = 8.0 Hz, 1 H), 6.93–6.90 (m,
1 H), 6.54 (s, 1 H).
found: 329.1193.
(2Z)-2-[(4-Methoxyphenyl)sulfanyl]undec-2-en-4-yn-1-ol (5j)
13C NMR (100 MHz, CDCl3): δ = 158.5, 149.5, 144.1, 138.5, 136.3,
131.6, 128.8, 128.50, 128.47, 128.2, 127.4, 123.4, 123.0, 120.1, 115.1,
99.1, 87.5.
HRMS (ESI-TOF): m/z [M + H]+ calcd for C21H16NS: 314.1003; found:
314.1007.
Pale yellow liquid; yield: 114.2 mg (75%).
FTIR (neat): 3420 (s), 2957 (s), 2931 (s), 2858 (m), 2214 (w), 1720 (w),
1593 (w), 1494 (s), 1287 (m), 1248 (s), 1030 (s), 829 cm–1 (m).
1H NMR (400 MHz, CDCl3): δ = 7.44 (d, J = 8.4 Hz, 2 H), 6.86 (d, J = 8.4
Hz, 2 H), 5.84 (s, 1 H), 3.98 (d, J = 5.5 Hz, 2 H), 3.80 (s, 3 H), 2.39 (t, J =
6.3 Hz, 2 H), 1.63–1.29 (m, 9 H), 0.88 (t, J = 6.6 Hz, 3 H).
(3Z)-2-Methyl-6-phenyl-3-(pyridin-2-ylsulfanyl)hex-3-en-5-yn-2-
ol (5o)
13C NMR (100 MHz, CDCl3): δ = 160.0, 146.7, 135.7, 121.4, 114.6,
107.5, 99.1, 76.9, 64.3, 55.3, 31.3, 28.6, 28.5, 22.5, 19.8, 14.0.
Yellow solid; yield: 107.8 mg (73%); mp 107–109 °C.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C18H24O2SNa: 327.1395;
FTIR (KBr): 3394 (s), 2927 (s), 2196 (w), 1570 (w), 1421 (m), 1208
(m), 1130 (w), 768 (m), 750 (m), 683 cm–1 (w).
found: 327.1398.
(3Z)-3-[(4-Chlorophenyl)sulfanyl]-2,7-dimethyloct-3-en-5-yne-
2,7-diol (5k)
1H NMR (400 MHz, CDCl3): δ = 8.36 (d, J = 4.8 Hz, 1 H), 7.51 (dt, J = 1.4,
7.6 Hz, 1 H), 7.36 (d, J = 8.1 Hz, 1 H), 7.25 (br s, 5 H), 7.02–6.99 (m, 1
H), 6.65 (s, 1 H), 5.10 (br s, 1 H), 1.55 (s, 6 H).
13C NMR (100 MHz, CDCl3): δ = 159.4, 150.8, 149.2, 136.7, 131.5,
128.5, 128.1, 122.8, 122.6, 120.2, 117.7, 98.4, 86.3, 73.4, 29.1.
Yellow gummy mass; yield: 118.1 mg (76%).
FTIR (neat): 3398 (s), 2981 (m), 2931 (w), 1719 (w), 1476 (s), 1363
(m), 1166 (m), 1091 (m), 1012 (w), 948 (m), 815 cm–1 (m).
1H NMR (400 MHz, CDCl3): δ = 7.24 (br s, 4 H), 6.44 (s, 1 H), 2.37 (br s,
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C18H17NOSNa: 318.0929;
found: 318.0916.
1 H), 1.94 (br s, 1 H), 1.47 (s, 6 H), 1.28 (s, 6 H).
13C NMR (100 MHz, CDCl3): δ = 152.8, 134.4, 131.6, 129.4, 128.8,
114.0, 104.0, 79.0, 74.5, 65.4, 30.7, 28.9.
[(1Z)-4-Phenyl-1-(phenylselanyl)but-1-en-3-ynyl]benzene (5q)3g
Pale yellow solid; yield: 120.3 mg (67%); mp 68–69 °C.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C16H19ClO2SNa: 333.0692;
FTIR (KBr): 3344 (s), 1577 (s), 1482 (m), 1460 (m), 1055 (m), 1021 (s),
622 cm–1 (s).
found: 333.0694.
(2Z)-2-[(4-Chlorophenyl)sulfanyl]undec-2-en-4-yn-1-ol (5l)
1H NMR (400 MHz, CDCl3): δ = 7.47–7.05 (m, 15 H), 6.40 (s, 1 H).
13C NMR (100 MHz, CDCl3): δ = 147.1, 139.3, 133.0, 131.4, 129.9,
Yellow liquid; yield: 100.4 mg (65%).
128.7, 128.3, 128.2, 128.0, 126.9, 123.2, 112.6, 97.6, 88.3.
FTIR (neat): 3402 (m), 2955 (m), 2930 (s), 2858 (m), 1719 (w), 1475
(m), 1277 (w), 1093 (m), 1012 (m), 820 (w), 747 cm–1 (m).
(3Z)-2,7-Dimethyl-3-(phenylselanyl)oct-3-en-5-yne-2,7-diol (5r)3g
Pale yellow solid; yield: 116.4 mg (72%); mp 104–106 °C.
© Georg Thieme Verlag Stuttgart · New York — Synthesis 2015, 47, 395–410

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C. Venkateswarlu, S. Chandrasekaran
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Synthesis
FTIR (neat): 3367 (s), 2980 (m), 1577 (w), 1438 (w), 1362 (m), 1209
(m), 1164 (s), 947 (m), 735 cm–1 (m).
1H NMR (400 MHz, CDCl3): δ = 7.44 (d, J = 7.3 Hz, 2 H), 7.27–7.18 (m, 3
H), 6.51 (s, 1 H), 2.39 (br s, 1 H), 1.79 (br s, 1 H), 1.50 (s, 6 H), 1.27 (s, 6
H).
13C NMR (100 MHz, CDCl3): δ = 153.3, 131.9, 130.4, 129.0, 126.3,
Compounds 6a–i; General Procedure
To a well stirred solution of 1,4-diorganylbuta-1,3-diyne (0.5 mmol, 1
equiv) in DMF–H2O (20:1; 4 mL), dichalcogenide (0.5 mmol, 1 equiv)
was added followed by the addition of rongalite (2.5 mmol, 5 equiv)
and K2CO3 (1.5 mmol, 3 equiv). The mixture was stirred at 70 °C for
the time indicated in Table 4. Then the mixture was allowed to attain
r.t. and water was added followed by extraction with EtOAc (2 × 20
mL). The organic layer was separated, then washed with brine, ex-
tracted with EtOAc (2 × 5 mL), and dried (anhyd Na2SO4). The solvent
was evaporated under vacuum and the crude product was purified by
column chromatography (silica gel, 230–400 mesh, EtOAc–petroleum
ether).
114.4, 102.4, 80.1, 74.8, 65.3, 30.7, 29.1.
(2Z)-2-(Phenylselanyl)hex-2-en-4-yne-1,6-diol (5s)
White solid; yield: 100.2 mg (75%); mp 113–115 °C.
FTIR (KBr): 3338 (s), 3263 (s), 2917 (w), 2211 (w), 1587 (w), 1410
(m), 1334 (m), 1085 (m), 1012 (s), 999 (s), 745 cm–1 (s).
1H NMR (400 MHz, CD3COCD3): δ = 7.62–6.30 (m, 6 H), 4.37–4.33 (m,
3 H), 4.24 (t, J = 6.1 Hz, 1 H), 4.02 (d, J = 6.0 Hz, 2 H).
[(1Z,3Z)-4-Phenyl-1,4-bis(phenylsulfanyl)buta-1,3-dienyl]ben-
zene (6a)2b
Yellow solid; yield: 107.1 mg (51%); mp 194–196 °C.
13C NMR (100 MHz, CD3COCD3): δ = 146.8, 135.3, 129.5, 128.5, 108.0,
96.0, 81.4, 65.1, 50.5.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C12H12O2SeNa: 290.9901;
found: 290.9903.
FTIR (KBr): 3051 (m), 1579 (m), 1478 (m), 1439 (w), 1075 (w), 1024
(w), 892 (m), 764 (s), 736 (s), 700 (s), 688 cm–1 (s).
1H NMR (400 MHz, CDCl3): δ = 7.75 (s, 2 H), 7.63 (d, J = 7.5 Hz, 4 H),
7.26–7.04 (m, 16 H).
13C NMR (100 MHz, CDCl3): δ = 139.6, 138.1, 135.6, 133.4, 128.8,
(3Z)-2-Methyl-6-phenyl-3-(phenylselanyl)hex-3-en-5-yn-2-ol (5u)
128.7, 128.3 (overlapped 2 signals), 127.9, 125.8.
Pale yellow oily liquid; yield: 116.0 mg (68%).
FTIR (neat): 3394 (s), 2976 (s), 2199 (w), 1577 (w), 1476 (w), 1362
(m), 1211 (m), 1174 (s), 828 (m), 756 (s), 735 (s), 689 cm–1 (s).
1H NMR (400 MHz, CDCl3): δ = 7.51–7.11 (m, 10 H), 6.71 (s, 1 H), 2.39
(3Z,5Z)-2,7-Dimethyl-3,6-bis(phenylsulfanyl)octa-3,5-diene-2,7-
diol (6b)
White solid; yield: 158.3 mg (82%); mp 152–153 °C.
(br s, 1 H), 1.51 (s, 6 H).
FTIR (KBr): 3300 (s), 2970 (m), 1581 (m), 1478 (m), 1440 (m), 1358
(m), 1171 (m), 1133 (m), 838 (s), 739 (s), 688 cm–1 (m).
1H NMR (400 MHz, CD3COCD3): δ = 7.42 (s, 2 H), 7.32 (t, J = 7.7 Hz, 4
H), 7.21–7.15 (m, 6 H), 3.93 (br s, 2 H), 1.27 (s, 12 H).
13C NMR (100 MHz, CD3COCD3): δ = 146.8, 138.8, 132.3, 129.7, 128.3,
13C NMR (100 MHz, CDCl3): δ = 153.4, 131.4, 131.2, 131.0, 129.0,
128.2, 128.0, 126.5, 122.9, 115.4, 97.2, 87.5, 75.0, 29.3.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C19H18OSeNa: 365.0421;
found: 365.0422.
126.3, 74.9, 29.7.
(2Z)-2-(Phenylselanyl)undec-2-en-4-yn-1-ol (5v)
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C22H26O2S2Na: 409.1272;
Yellow liquid; yield: 99.6 mg (62%).
found: 409.1273.
FTIR (neat): 3370 (s), 2954 (m), 2930 (s), 2858 (m), 2215 (w), 1088
(w), 1009 (w), 740 cm–1 (m).
(2Z,4Z)-2,5-Bis(phenylsulfanyl)hexa-2,4-diene-1,6-diol (6c)
1H NMR (400 MHz, CDCl3): δ = 7.61 (d, J = 7.5 Hz, 2 H), 7.33–7.26 (m, 3
H), 6.15 (s, 1 H), 4.05 (d, J = 4.4 Hz, 2 H), 2.37 (t, J = 6.9 Hz, 2 H), 1.68–
1.26 (m, 9 H), 0.89 (t, J = 6.9 Hz, 3 H).
13C NMR (100 MHz, CDCl3): δ = 144.3, 135.2, 129.2, 128.3, 126.9,
111.0, 98.7, 77.7, 65.8, 31.3, 28.6, 28.5, 22.5, 19.7, 14.0.
White solid; yield: 140.4 mg (85%); mp 133–135 °C.
FTIR (KBr): 3253 (s), 3158 (m), 2899 (w), 1582 (m), 1478 (m), 1440
(m), 1070 (s), 978 (m), 893 (m), 736 (s), 688 cm–1 (m).
1H NMR (400 MHz, CD3COCD3): δ = 7.61 (s, 2 H), 7.34–7.23 (m, 10 H),
4.47 (t, J = 5.9 Hz, 2 H), 4.15 (d, J = 5.9 Hz, 4 H).
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C17H22OSeNa: 345.0734;
found: 345.0730.
13C NMR (100 MHz, CD3COCD3): δ = 138.6, 135.3, 130.3, 130.0, 129.9,
127.4, 65.4.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C18H18O2S2Na: 353.0646;
[(3Z)-4-(Phenylselanyl)dec-3-en-1-ynyl]benzene (5w)
found: 353.0645.
Yellow liquid; yield: 77.1 mg (42%).
FTIR (neat): 3424 (m), 2955 (m), 2928 (s), 2855 (m), 1579 (m), 1439
(m), 1022 (w), 755 (s), 740 (m), 690 cm–1 (m).
1H NMR (400 MHz, CDCl3): δ = 7.63–7.28 (m, 10 H), 6.00 (s, 1 H), 2.19
(t, J = 7.4 Hz, 2 H), 1.42–1.12 (m, 8 H), 0.83 (t, J = 7.1 Hz, 3 H).
13C NMR (100 MHz, CDCl3): δ = 150.9, 135.8, 131.3, 129.0, 128.19,
128.17, 128.0, 127.9, 123.5, 107.9, 95.4, 87.3, 37.4, 31.4, 28.9, 28.3,
22.4, 14.0.
(3Z,5Z)-2-Methyl-6-phenyl-3,6-bis(phenylsulfanyl)hexa-3,5-dien-
2-ol (6d)
Gummy mass; yield: 107.2 mg (53%).
FTIR (neat): 3413 (br), 1653 (br), 1219 (w), 1018 (m), 772 cm–1 (s).
1H NMR (400 MHz, CDCl3): δ = 7.61 (d, J = 10.4 Hz, 1 H), 7.41–7.04 (m,
16 H), 2.22 (br s, 1 H), 1.47 (s, 6 H).
77Se NMR (100 MHz, CDCl3): δ = 428.3.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C22H24SeNa: 391.0941;
13C NMR (100 MHz, CDCl3): δ = 144.8, 139.6, 139.4, 137.1, 135.7,
133.0, 132.3, 129.1, 128.9, 128.8, 128.5, 128.3, 128.0, 127.2, 126.0,
125.7, 75.1, 29.4.
found: 391.0939.
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HRMS (ESI-TOF): m/z [M + Na]+ calcd for C25H24OS2Na: 427.1166;
1H NMR (400 MHz, CDCl3): δ = 7.48–7.45 (m, 4 H), 7.31 (s, 2 H), 7.28–
found: 427.1170.
7.26 (m, 6 H), 4.19 (s, 4 H), 1.88 (br s, 2 H).
13C NMR (100 MHz, CDCl3): δ = 138.2, 132.7, 131.6, 129.4, 128.8,
127.5, 67.1.
(2Z,4Z)-2,5-Bis[(4-methylphenyl)sulfanyl]hexa-2,4-diene-1,6-diol
(6e)
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C18H18O2Se2Na: 448.9535;
found: 448.9531.
White solid; yield: 154.2 mg (86%); mp 147–149 °C.
FTIR (KBr): 3247 (br), 2920 (m), 1492 (m), 1074 (s), 1029 (s), 879 (m),
808 cm–1 (s).
Hydrochalcogenation of (Z)-(Chalcogeno)enynes; General Proce-
1H NMR (400 MHz, CD3COCD3): δ = 7.53 (s, 2 H), 7.24 (d, J = 8.0 Hz, 4
H), 7.16 (d, J = 8.0 Hz, 4 H), 4.35 (t, J = 6.0 Hz, 2 H), 4.11 (d, J = 5.9 Hz, 4
H), 2.31 (s, 6 H).
dure
To a stirred solution of (Z)-(chalcogeno)enyne (0.5 mmol, 1 equiv), di-
chalcogenide (0.25 mmol, 0.5 equiv) in DMF–H2O (20:1; 4 mL), ron-
galite (1.5 mmol, 3 equiv), and K2CO3 (1 mmol, 2 equiv) were added
and the mixture was stirred at 70 °C for the time indicated in Table 5.
Then the mixture was allowed to attain r.t. and water was added fol-
lowed by extraction with EtOAc (2 × 20 mL). The organic layer was
separated, then washed with brine, extracted with EtOAc (2 × 5 mL),
and dried (anhyd Na2SO4). The solvent was evaporated under vacuum
and the crude product was purified by column chromatography (sili-
ca gel, 230–400 mesh, EtOAc–petroleum ether).
13C NMR (100 MHz, CD3COCD3): δ = 139.0, 137.7, 131.4, 131.1, 130.7,
128.8, 65.3, 21.0.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C20H22O2S2Na: 381.0959;
found: 381.0959.
(3Z,5Z)-3,6-Bis[(4-chlorophenyl)sulfanyl]-2,7-dimethylocta-3,5-
diene-2,7-diol (6f)
White solid; yield: 173.1 mg (76%); mp 134–136 °C.
(2Z,4Z)-2-[(4-Chlorophenyl)sulfanyl]-5-(phenylsulfanyl)hexa-2,4-
diene-1,6-diol (6j)
FTIR (KBr): 3314 (br), 2971 (m), 2929 (w), 1475 (m), 1358 (w), 1172
(m), 1093 (m), 1012 (w), 836 (m), 817 cm–1 (m).
1H NMR (400 MHz, CDCl3): δ = 7.22 (d, J = 8.4 Hz, 4 H), 7.17 (s, 2 H),
7.10 (d, J = 8.4 Hz, 4 H), 2.04 (br s, 2 H), 1.32 (s, 12 H).
White solid; yield: 146.0 mg (80%); mp 138–140 °C.
FTIR (KBr): 3449 (br), 1648 (m), 1090 (w), 1068 (m), 1010 cm–1 (w).
13C NMR (100 MHz, CDCl3): δ = 146.6, 135.6, 131.7, 131.2, 129.1,
1H NMR (400 MHz, DMSO-d6): δ = 7.49–7.24 (m, 11 H), 5.44–5.39 (m,
128.9, 74.5, 29.0.
2 H), 3.99–3.96 (m, 4 H).
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C22H24Cl2O2S2Na: 477.0492;
13C NMR (100 MHz, DMSO-d6): δ = 138.6, 137.2, 134.2, 133.7, 131.7,
found: 477.0491.
130.9, 129.8, 129.69, 129.66, 129.6, 128.5, 127.2, 64.2, 64.1.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C18H17ClO2S2Na: 387.0256;
found: 387.0256.
[(1Z,3Z)-4-Phenyl-1,4-bis(phenylselanyl)buta-1,3-dienyl]benzene
(6g)
Pale yellow solid; yield: 69.8 mg (27%); mp 182–184 °C.
(2Z,4Z)-2-[(4-Chlorophenyl)sulfanyl]-5-[4-(methylphenyl)sulfa-
nyl]hexa-2,4-diene-1,6-diol (6k)
FTIR (KBr): 3446 (br), 2922 (w), 2852 (w), 1646 (w), 1436 (m), 1250
(w), 1021 (w), 873 (m), 762 (s), 738 (s), 688 cm–1 (s).
White solid; yield: 155.4 mg (82%); mp 162–164 °C.
1H NMR (400 MHz, CDCl3): δ = 7.61 (s, 2 H), 7.56 (d, J = 7.7 Hz, 4 H),
FTIR (KBr): 3455 (br), 1640 (w), 1086 (m), 1030 (m), 882 cm–1 (w).
7.30–7.11 (m, 16 H).
13C NMR (100 MHz, CDCl3): δ = 141.1, 138.3, 135.6, 131.2, 131.1,
129.0, 128.4, 128.21, 128.16, 126.4.
1H NMR (400 MHz, CDCl3): δ = 7.51–7.16 (m, 10 H), 5.43 (t, J = 5.8 Hz,
1 H), 5.34 (t, J = 5.8 Hz, 1 H), 3.98 (d, J = 5.5 Hz, 2 H), 3.92 (d, J = 5.3 Hz,
2 H), 2.28 (s, 3 H).
13C NMR (100 MHz, CDCl3): δ = 139.5, 137.1, 136.6, 133.8, 131.6,
Anal. Calcd for C28H22Se2: C, 65.12; H, 4.29. Found: C, 65.29; H, 4.41.
130.7, 130.5, 130.4, 130.0, 129.8, 129.7, 127.1, 64.3, 63.9, 21.0.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C19H19ClO2S2Na: 401.0413;
found: 401.0415.
(3Z,5Z)-2,7-Dimethyl-3,6-bis(phenylselanyl)octa-3,5-diene-2,7-
diol (6h)
Pale yellow solid; yield: 89.3 mg (37%); mp 147–149 °C.
(3Z,5Z)-2,7-Dimethyl-3-(phenylselanyl)-6-(phenylsulfanyl)octa-
3,5-diene-2,7-diol (6l)
FTIR (KBr): 3298 (s), 2970 (s), 1676 (m), 1576 (m), 1476 (m), 1358
(m), 1133 (m), 888 (m), 824 (m), 733 (s), 688 cm–1 (m).
1H NMR (400 MHz, CDCl3): δ = 7.30–7.19 (m, 10 H), 7.02 (s, 2 H), 3.03
White solid; yield: 112.7 mg (52%); mp 155–157 °C.
(br s, 2 H), 1.29 (s, 12 H).
13C NMR (100 MHz, CDCl3): δ = 147.6, 136.6, 131.8, 130.5, 129.1,
126.4, 74.6, 29.1.
FTIR (KBr): 3307 (br), 2970 (s), 1578 (w), 1476 (m), 1358 (m), 1168
(m), 1133 (m), 888 (m), 833 (m), 735 (s), 688 cm–1 (m).
1H NMR (400 MHz, CDCl3): δ = 7.34 (d, J = 7.8 Hz, 2 H), 7.27–7.02 (m,
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C22H26O2Se2Na: 505.0161;
found: 505.0163.
10 H), 2.13 (br s, 1 H), 2.04 (br s, 1 H), 1.31 (s, 6 H), 1.27 (s, 6 H).
13C NMR (100 MHz, CDCl3): δ = 148.4, 145.7, 137.1, 132.6, 132.5,
130.7, 129.8, 129.1, 128.9, 127.7, 126.5, 125.7, 74.6, 74.4, 29.1, 28.9.
HRMS (ESI-TOF): m/z [M + Na]+ calcd for C22H26O2SSeNa: 457.0717;
(2Z,4Z)-2,5-Bis(phenylselanyl)hexa-2,4-diene-1,6-diol (6i)
Pale yellow solid; yield: 92.4 mg (44%); mp 118–119 °C.
found: 457.0737.
FTIR (KBr): 3266 (m), 2896 (w), 2847 (w), 1576 (m), 1474 (w), 1232
(w), 1060 (s), 1021 (m), 886 (m), 730 (s), 687 cm–1 (m).
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Acknowledgment
(6) (a) Freeman, F.; Lu, H.; Zeng, Q.; Rodriguez, E. J. Org. Chem. 1994,
59, 4350. (b) Dabdoub, M. J.; Dabdoub, V. B.; Lenardão, E. J.;
Hurtado, G. R.; Barbosa, S. L.; Guerrero, P. G.; Nazário, C. E. D.;
Viana, L. H.; Santana, A. S.; Baroni, A. C. M. Synlett 2009, 986.
(c) Volkov, A. N.; Volkova, K. A. Russ. J. Org. Chem. 2004, 40,
1679.
C.V.R. thanks the CSIR for a Shyama Prasad Mukherjee (SPM) Senior
Research Fellowship, and S.C.N. thanks the Department of Science
and Technology (DST) for the award of SERB Distinguished Fellow and
the JNCASR, Jakkur for the Hindustan Lever Professorship.
(7) Santana, A. S.; Carvalho, D. B.; Casemiro, N. S.; Hurtado, G. R.;
Viana, L. H.; Kassab, N. M.; Barbosa, S. L.; Marques, F. A.;
Guerrero, P. G. Jr.; Baroni, A. C. M. Tetrahedron Lett. 2012, 53,
5733.
(8) (a) Alves, D.; Luchese, C.; Nogueira, C. W.; Zeni, G. J. Org. Chem.
2007, 72, 6726. (b) Schumacher, R. F.; Alves, D.; Brandão, R.;
Nogueira, C. W.; Zeni, G. Tetrahedron Lett. 2008, 49, 538.
(c) Barancelli, D. A.; Acker, C. I.; Menezes, P. H.; Zeni, G. Org.
Biomol. Chem. 2011, 9, 1529.
Supporting Information
Supporting information for this article is available online at
http://dx.doi.org/10.1055/s-0034-1379330.
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