Iodine-catalyzed Sulfonylation of Arylacetylenic Acids and Arylacetylenes with Sodium Sulfinates: Synthesis of Arylacetylenic Sulfones

Article abstract of DOI:10.1021/acs.joc.5b02810

A highly efficient and generally applicable iodine-catalyzed reaction of arylacetylenic acids and arylacetylenes with sodium sulfinates for the synthesis of arylacetylenic sulfones was developed. The methodology has the advantages of a metal-free strategy, easy to handle reagents, functional group tolerance, a wide range of arylacetylenic acids and arylacetylenes, and easy access to arylacetylenic sulfones. (Chemical Equation Presented).

Full text of DOI:10.1021/acs.joc.5b02810

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Article
Iodine-catalyzed Sulfonylation of Arylacetylenic Acids and Arylacetylenes
with Sodium Sulfinates: Synthesis of Arylacetylenic Sulfones
Jatuporn Meesin, Praewpan Katrun, Chayaporn Pareseecharoen, Manat
Pohmakotr, Vichai Reutrakul, Darunee Soorukram, and Chutima Kuhakarn
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.5b02810 • Publication Date (Web): 10 Mar 2016
Downloaded from http://pubs.acs.org on March 12, 2016
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Iodineꢀcatalyzed Sulfonylation of Arylacetylenic Acids
and Arylacetylenes with Sodium Sulfinates: Synthesis
of Arylacetylenic Sulfones
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Jatuporn Meesin, Praewpan Katrun, Chayaporn Pareseecharoen, Manat Pohmakotr, Vichai Reutrakul,
Darunee Soorukram and Chutima Kuhakarn*
Department of Chemistry and Center of Excellence for Innovation in Chemistry (PERCHꢀCIC), Faculty
of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand.
Eꢀmail: chutima.kon@mahidol.ac.th
Table of Contents (TOC) Graphic
A highly efficient and generally applicable iodineꢀcatalyzed reaction of arylacetylenic acids and
arylacetylenes with sodium sulfinates for the synthesis of arylacetylenic sulfones was developed.
The methodology has advantages of a metalꢀfree strategy, easy to handle reagents, functional
group tolerance, a wide range of arylacetylenic acids and arylacetylenes and easy access to
arylacetylenic sulfones.
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Introduction
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Sulfurꢀcontaining compounds are of great importance in organic synthesis,
pharmaceuticals, bioactive products, medicines, agrochemicals, semiconductors, and organic
dyes. Among them, organosulfone compounds have attracted enormous attention, because they
occur in a number of compounds exhibiting important biological activities1 and show
tremendous synthetic utilities.2 Therefore, the development of general methods for the synthesis
of organosulfone compounds is consequently an important goal in organic chemistry. The
construction of the C–SO2 bond is important, and the installation of sulfone moiety into the
organic molecules via C–SO2 bond formation has thereby drawn remarked attentions.3 A number
of sulfonyl precursors including sulfonyl halides,4 sulfonyl selenides,5 sulfonyl cyanides,6
sulfonyl azides,7 sulfonyl hydrazides,8 sodium sulfinates,9 sulfinic acids10 and sulfoxides11 were
employed to access organosulfone compounds.
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Acetylenic sulfones are important class of organosulfone compounds and their synthetic
applications are well documented.12 A number of synthetic routes are available toward the
synthesis of acetylenic sulfones.13 Most recently, Singh and coworkers described, in part, a
combination of arylsulfonyl hydrazide, molecular iodine (I2), tertꢀbutyl hydroperoxide (TBHP),
DBU in aqueous acetonitrile to access acetylenic sulfones from 3ꢀphenylpropiolic acid.13e
Although the reported methods for acetylenic sulfone synthesis are highly efficient, alternative
methodologies employing commercially available starting materials and operationally simple
methods are still desirable. With our continuing interests in developing efficient methods for the
synthesis of organosulfur compounds,14 we report herein our research results on the combination
of I2ꢀTBHP mediated decarboxylative sulfonylation of arylacetylenic acids and sulfonylation of
arylacetylenes employing sodium sulfinates as sulfur sources (Scheme 1). Our method offers
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several advantages, including being transitionꢀmetalꢀfree, employing stable reagents, involving
simple handling under airꢀstable conditions, accommodating a variety of substrates, and avoiding
the formation of toxic byproducts.
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Scheme 1. Iodineꢀcatalyzed Sulfonylation of Arylacetylenic Acids and Arylacetylenes with
Sodium Sulfinates
Results and Discussion
To evaluate the potential for acetylenic sulfone formation, the reaction between 3ꢀ
phenylpropiolic acid (1a) and sodium pꢀtoluenesulfinate (2a) was examined under various
reaction parameters in order to screen for the optimum reaction conditions and the results are
summarized in Table 1. To our delight, when 3ꢀphenylpropiolic acid (1a, 0.5 mmol) was treated
with sodium pꢀtoluenesulfinate (2a, 3 equiv) with molecular iodine (I2, 1 equiv), tertꢀ
butylhydroperoxide (TBHP, 5 equiv), potassium carbonate (K2CO3, 1 equiv) in acetonitrile (2
o
mL) and the resulting mixture was stirred at room temperature (30‒32 C) for 24 h, the
corresponding acetylenic sulfone 3a was obtained in 51% yield (Table 1, entry 1). Next various
solvents, including ethanol, tetrahydrofuran, 1,4ꢀdioxane, dichloroethane and toluene, were
screened (Table 1, entries 2‒6). Among those, tetrahydrofuran was found being an optimum
solvent yielding 3a in significantly improved yield (88% yield, Table 1, entry 3). It is pleasing to
find that reaction time can be shortened (from 24 h to 16 h) and comparable yield of 3a was
observed (Table 1, entry 7). The amount of sodium pꢀtoluenesulfinate (2a) employed can be as
low as 2 equivalents; further reduction of the amount of 2a caused drastic decrease in product
yield (Table 1, entries 8‒9). Further attempts to highlight the role of reagents employed were
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also investigated. External base (K2CO3) can be excluded from the reaction without affecting the
reaction efficiency (Table 1, entry 10). Furthermore, the stoichiometry of TBHP can be lowered
(from 5 equiv to 3 equiv) and molecular iodine can be employed in substoichiometric quantity
(50 mol%) (Table 1, entries 11‒12). Effort to drive the reaction to completion by conducting the
reaction in refluxing THF for 9 h was unsuccessful; there was no improvement in yield but a
significant decrease in product yield was observed (Table 1, entry 12). Further decrease in the
iodine quantity (from 0.5 equiv to 0.25 equiv) led to poorer results (Table 1, entry 13). Finally,
the reaction did not take place in the absence of molecular iodine catalyst and only trace amount
of 3a was observed (TLC analysis) when TBHP was excluded from the reaction (Table 1, entries
14‒15). The observed results further emphasized the important roles of both molecular iodine
and TBHP in the present reaction. It is worth also mentioned here that attempts to replace
aqueous TBHP with TBHP in decane or other peroxide reagents including aqueous hydrogen
peroxide, cumene hydroperoxide, diꢀtertꢀbutyl peroxide, diꢀcumyl peroxide, and tertꢀbutyl
benzoperoxoate gave inferior results.
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Table 1. Optimization of the Reaction Conditions for Iodineꢀcatalyzed Decarboxylative
Sulfonylation of 3ꢀPhenylpropiolic acid (1a)a
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entry
I2
aq TBHP K2CO3
Solvent
time (h)
yieldb (%)
2a
(equiv)
(equiv)
1
1
1
1
1
1
1
1
1
1
1
0.5
0.25
‒
(equiv)
(equiv)
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2
3
4
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8
3
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3
3
2
1
2
2
2
2
2
2
5
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5
5
5
5
5
5
5
5
3
3
3
3
‒
1
1
1
1
1
1
1
1
1
‒
‒
‒
‒
‒
‒
CH3CN
EtOH
THF
1,4ꢀDioxane
Dichloroethane
Toluene
THF
THF
THF
THF
THF
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24
24
24
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24
16
16
16
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16
16
16
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16
51
43
88
72
Trace
Trace
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86
59
9
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14
87
85
THF
THF
THF
THF
86 (65)c
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d
‒
15
0.5
Trace
a
o
b
Reaction conditions: 1a (0.5 mmol) in solvent (2 mL), rt (30‒32 C), open air. Isolated yields after column
chromatography (SiO2). c Reaction was performed in refluxing THF (9 h). d 3a was not observed (TLC analysis).
After extensive experimentation, the optimum reaction conditions for the iodineꢀ
catalyzed decarboxylative sulfonylation of arylacetylenic acids were chosen as follows: 1a (1
equiv), 2a (2 equiv), I2 (50 mol%), TBHP (3 equiv) in THF at room temperature for 16 h (Table
1, entry 12). With the optimized reaction conditions in hand, we next explored the generality and
functional group compatibility of this transformation under the established reaction conditions
and the results are summarized in Tables 2 and 3.
Initially, the scope of the decarboxylative sulfonylation of 3ꢀphenylpropiolic acid (1a)
with a collection of sodium sulfinates was investigated as shown in Table 2. The reactions of 3ꢀ
phenylpropiolic acid (1a) with sodium arenesulfinates bearing electronically different groups on
the para position (pꢀCH3, pꢀOCH3, pꢀCl, pꢀBr) gave the corresponding products 3a–3e in low to
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good yields (29‒86% yields); sodium pꢀbromobenzenesulfinates is being a poor sulfinate salt.
Under standard reaction conditions, sodium methanesulfinate gave the corresponding product 3f
in low yield (20% yield). On the other hand, we observed no acetylenic sulfones formed when
sterically hindered sodium mesitylenesulfinate and electron deficient sulfinates including sodium
2,4ꢀdinitrobenzenesulfinate and sodium trifluoromethanesulfinate were employed; unidentifiable
polar mixture was observed (TLC analysis).
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Table 2. Scope of Sodium Sulfinatesa
3a (86%)
3d (82%)
3b (83%)
3e (29%)
3c (61%)
3f (20%)
a Conditions: 1a (0.5 mmol), 2 (2 equiv), I2 (0.5 equiv), 70% TBHP in H2O (3 equiv) in THF (2 mL), rt
o
(30‒32 C), 16 h. In parenthesis: isolated yields after chromatographic purification (SiO2 column
chromatography).
Next, the reactions between various types of arylacetylenic acids 1 with sodium pꢀ
toluenesulfinate (2a) were examined as shown in Table 3. Under the established reaction
conditions, the reactions of sodium pꢀtoluenesulfinate (2a) with electronically different paraꢀ
substituted arylacetylenic acid derivatives (pꢀCH3, pꢀOCH3, and pꢀCF3) smoothly gave the
corresponding products 3g–3i in good yields (68–90% yields). In case of paraꢀhalosubstituted
arylacetylenic acids (pꢀF and pꢀBr), the corresponding acetylenic sulfones 3j–3k were obtained
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in moderate quantities (47‒80% yields). Arylacetylenic acid bearing strong electronꢀattracting
group (pꢀNO2) was also suitable for this process, albeit diverting to the corresponding acetylenic
sulfone 3l in relatively low yield (32% yield). Arylacetylenic acids bearing substituents at the
meta position (mꢀCH3, and mꢀCl) could also be converted to their corresponding acetylenic
sulfones 3m–3n in high yields (69‒90% yields). The electronic and steric effects were evident
when 3ꢀ(2ꢀbromophenyl)propiolic acid was employed as a starting material; an evident decrease
of reaction yield of 3o was observed. Notably, arylacetylenic acids bearing substituents at the
ortho and para positions were also effective substrates in this transformation furnishing the
corresponding products 3p−3q in good yields (67‒83% yields). 3ꢀ(Naphthalenꢀ2ꢀyl)propiolic
acid and 3ꢀheteroarylpropiolic acid, i.e. 3ꢀ(thiophenꢀ2ꢀyl)propiolic acid, are also good substrates
providing 3r and 3s in 53% and 63% yields, respectively. Nevertheless, the present protocol was
found incompatible with βꢀalkylꢀ and βꢀsilylꢀsubstituted propiolic acids. 2ꢀButynoic acid failed
to give any desired acetylenic sulfone product. Efforts to employ 3ꢀ(triisopropylsilyl)propiolic
acid and 3ꢀ(tertꢀbutyldimethylsilyl)propiolic acid as the substrates were also examined albeit
without success; the starting acids were recovered in both cases. Noteworthy, a scaling up
experiment (5 mmol) between 1a and 2a was also investigated under the optimized conditions
and 3a was obtained in comparable efficiency (82% yield).
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Table 3. Scope of Arylacetylenic Acidsa
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3g
3h
3i
3j
3k
3l
R = CH3
R = OCH3 (80%)
R = CF3
R =F
R =Br
(90%)
3m
3n
R = CH3
R = Cl
(90%)
(69%)
3o (35%)
(68%)
(47%)
(80%)
(32%)
R = NO2
3p
3q
R = CH3
R = OCH3
(67%)
(83%)
3r (53%)
3s (63%)
a Conditions: 1a (0.5 mmol), 2 (2 equiv), I2 (0.5 equiv), 70% TBHP in H2O (3 equiv) in THF (2 mL), rt (30‒32
oC), 16 h. In parenthesis: isolated yields after chromatographic purification (SiO2 column chromatography).
To gain a better understanding of the reaction mechanism, a series of control experiments
were carried out (Scheme 2). The reaction of 3ꢀphenylpropiolic acid (1a) with sodium pꢀ
toluenesulfinate (2a) was conducted under the standard reaction conditions in the presence of
radical inhibitors, including hydroquinone and 2,2,6,6ꢀtetramethylꢀ1ꢀpiperidinyloxy (TEMPO)
[Scheme 2, (a)]. Hydroquinone was found to retard the reaction while TEMPO almost ceased the
reaction. Although the radicalꢀtrapping adducts were not isolated, the observed results implied
that the reaction is likely to involve a radical pathway. There has been a previous report that
arylpropiolic acids were capable of undergoing halodecarboxylation to provide 1ꢀhaloalkynes.15
We then separately prepared (iodoethynyl)benzene (4)16 and employed 4 in place of 3ꢀ
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phenylpropiolic acid (1a) the under standard reaction conditions. Interestingly, 3a was isolated in
53% yield, suggesting that 4 might also be an intermediate in the present reaction [Scheme 2,
(b)]. However, under the standard reaction conditions but in the absence of 2a, 1a did not
provide any isolable products [Scheme 2, (c)]. GC/MS analysis of the reaction mixture before
aqueous workꢀup indicated the formation of phenylacetylene (5a). However, after aqueous workꢀ
up, 1a was recovered in 90% yield. This observation suggested that under the reaction
conditions, 1a was unlikely converted to either 4 or 5a. Indeed, decarboxylative sulfonylation of
1a to 3a is unlikely to proceed through the intermediate 4 or 5a. The detection of 5a urged us to
investigate the reaction of phenylacetylene (5a) and sodium pꢀtoluenesulfinate (2a) under our
standard reaction conditions [Scheme 2, (d)]. Gratifyingly, we were pleased to observe that 5a
reacted with 2a under the standard conditions, yielding the corresponding acetylenic sulfone 3a
in moderate yield (56% yield). Next, the reactions of 3ꢀphenylpropiolic acid (1a) and
phenylacetylene (5a) with pꢀtoluenesulfonyl iodide17 were examined [Scheme 2, (e)]. To our
surprise, acetylenic sulfone 3a was not observed in both cases; interestingly, phenylacetylene
(5a) yielded (E)ꢀ(1ꢀiodoꢀ2ꢀ(phenylsulfonyl)vinyl)benzene (6a) in 83% yield. This outcome
suggested that sulfonyl iodide is unlikely being a key precursor to react with 1a or 5a to lead to
acetylenic sulfone 3a. Finally, it was found that sulfonyl iodide cannot be generated upon
treatment of sodium pꢀtoluenesulfinate (2a) with molecular iodine in THF at room temperature
[Scheme 2, (f)]. On the contrary, under our standard reaction conditions (I2, TBHP, THF, rt), the
sulfonyl iodide can be detected (TLC analysis) but disappeared upon stirring overnight [Scheme
2, (f)].
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Scheme 2. Control Experiments
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(b)
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On the basis of the results described above and relevant literature,13 tentative reaction
mechanisms for this metalꢀfree decarboxylative sulfonylation of arylacetylenic acids is proposed
using 3ꢀphenylpropiolic acid (1a) and sodium pꢀtoluenesulfinate (2a) as the model substrates
(Scheme 3). Since the reactions were extremely sluggish or did not occur if neither I2 nor TBHP
was employed under the typical reaction conditions (Table 1, entries 14‒15), this observation
implied that to lead to the desired acetylenic sulfones both of the I2 and TBHP did not directly
react with substrates during the reaction. Indeed, two possible pathways are proposed for the in
situ generation of sulfonyl radical intermediate [Scheme 3, (b)]. In the presence of iodine/TBHP,
sodium pꢀtoluenesulfinate will be oxidized to preferably generate the oxygenꢀcentered sulfonyl
radical A. The oxygenꢀcentered radical A exists as an equilibrium with the sulfurꢀcentered
sulfonyl radical B which then react with the substrates (3ꢀarylpropiolic acids or arylacetylenes)
(Path A). Alternatively, iodine/TBHP readily reacted to form a more reactive electrophilic iodine
species [Scheme 3, (a)]13e which then reacted with sodium pꢀtoluenesulfinates to generate pꢀ
toluenesulfinylhypoiodite C (Path B). The pꢀtoluenesulfinylhypoiodite C could exist in
equilibrium with its corresponding pꢀtoluenesulfonyl iodide D and subsequently underwent
homolytic cleavage to yield oxygenꢀcentered sulfonyl radical A, and finally to the sulfurꢀ
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centered sulfonyl radical B. Upon employing 3ꢀphenylpropiolic acid (1a) as a starting
compound, the sulfonyl radical B underwent direct addition to 1a to generate the vinyl radical
intermediate E which then subsequently underwent decarboxylation to provide the acetylenic
sulfone 3a [Scheme 3, (c)].18 For the conversion of phenylacetylene (5a) to acetylenic sulfone
3a, addition of the sulfonyl radical B to 5a generated a vinyl radical intermediate F [Scheme 3,
(c)].13d The acetylenic sulfone 3a was obtained upon elimination of hydrogen radical. In this
work, the (iodoethynyl)benzene (4) can also be converted to acetylenic sulfone 3a through a
similar pathway via a proposed intermediate G [Scheme 3, (c)]. Finally, the HI generated in the
reaction could be reoxidized leading to I2 to resume the catalytic cycle [Scheme 3, (d)].19
Scheme 3. Proposed Reaction Mechanism
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(a) Formation of electrophilic iodine species
(b) Formation of sulfonyl radical
Path A
O
S
O
O
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pTol
pTol S O
pTol S ONa
O
A
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Path B
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I2, TBHP
- I
O
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pTol
S
O
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pTol S O I
C
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c) Formation of acetylenic sulfones
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d) Regeneration of molecular iodine
The synthetic utility of the present protocol was further extended to the sulfonylation of
arylacetylenes. The reaction of electronically different arylacetylenes 5 with sodium
arenesulfinates 2 under the established reaction conditions for decarboxylative sulfonylaion of
arylacetylenic acids 1 was evaluated and the results were summarized in Table 4. Delightfully,
arylacetylenes 5 were found capable of undergoing sulfonylation reaction to yield the respective
arylacetylenic sulfones 3, albeit in lower efficiency. Except for 3l where trace amount of the
product was observed (TLC analysis), the yields were moderate (42−68% yields). Arylacetylenes
bearing electronꢀwithdrawing substituents gave poorer yields in comparison to those bearing
electronꢀreleasing substituents. While the reaction of phenylacetylene with sodium pꢀ
bromobenzenesulfinate gave acetylenic sulfone 3e in low yield (17% yield), those with sodium
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mesitylenesulfinate and sodium 2,4ꢀdinitrobenzenesulfinate did not provide the desired products.
This observation is in accordance with those observed when arylacetylenic acids were employed
as the starting compounds (Tables 2 and 3). Interestingly, under the standard reaction conditions
[I2 (0.5 equiv), 70% TBHP in H2O (3 equiv), THF, rt, 16 h], terminal aliphatic alkyne, 1ꢀoctyne,
did not yield alkylacetylenic sulfone but led to the corresponding (E)ꢀβꢀiodovinyl sulfone 6b
(confirmed by NOE experiments) in low yield (26% yield) [Scheme 4, (a)]. Notably, internal
alkynes, under the established reaction conditions, also yielded the corresponding (E)ꢀβꢀ
iodovinyl sulfones 6c−6e, albeit in low yields (14−27% yields) [Scheme 4, (b)].
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Table 4. Sulfonylation of Arylacetylenes 5a
3a
3g
3h
3j
R = H
R = CH3
R = OCH3 (62%)
R = F
(56%)
(68%)
3o (49%)
3t (42%)
3b
3c
3d
3e
R1 = H
(54%)
(45%)
(46%)
(17%)
R1 = OCH3
R1 = Cl
(55%)
Trace
R1 = Br
3l
R = NO2
a Conditions: 1a (0.5 mmol), 2 (2 equiv), I2 (0.5 equiv), 70% TBHP in H2O (3 equiv) in THF (2 mL), rt (30‒32
oC), 16 h. In parenthesis: isolated yields after chromatographic purification (SiO2 column chromatography).
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Scheme 4. Reaction of Terminal Aliphatic Alkyne and Internal Alkynes
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6
(a) Terminal aliphatic alkyne
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I
I2, TBHP
H
pTolSO2Na
C6H13
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+
C6H13
THF, rt, 16 h
SO2pTol
6b, 26%
(b) Internal alkynes
Conclusion
In summary, a highly efficient synthesis of arylacetylenic sulfones has been developed.
Under identical reaction conditions, arylacetylenic acids underwent decarboxylative
sulfonylation while arylacetylenes underwent sulfonylation to yield the acetylenic sulfones in
moderate to excellent yields. The established methodology offers a benign metalꢀfree protocol,
ease of experimentation (room temperature) and openꢀflask reaction. The expansion of the
synthetic application of this chemistry is currently under investigation in our laboratory.
Experimental Section
General Procedure: All isolated compounds were characterized on the basis of 1H NMR, 13C
NMR spectroscopic data, IR spectra and HRMS data. 1H NMR and 13C NMR chemical shifts are
reported in ppm using tetramethylsilane (TMS) as an internal standard or residual nonꢀdeuterated
solvent peak as an internal standard.
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General Procedure for the Synthesis of Arylpropiolic acids20
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Aryl iodide (5.0 mmol), DBU (1.83 g, 12 mmol, 2.4 equiv.), Pd(PPh3)4 (144 mg, 2.5 mol%) were
mixed in DMSO (6 mL). The solution of propiolic acid (420 mg, 6.0 mmol, 1.2 equiv.) in DMSO (6
mL) was poured to the flask. The mixture was stirred at room temperature for 12 h. After the reaction
completely occurred, EtOAc (20 mL) was poured into the reaction mixture. The reaction mixture was
extracted with saturated aqueous NaHCO3 solution. The aqueous layer was separated, acidified to pH
2.0 by adding cold HCl (1 N), and extracted with CH2Cl2. The combined organic layers were dried
with anhydrous Na2SO4, filtered, and the solvent was removed under reduced pressure. The resulting
crude product was purified by column chromatography on silica gel.
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General Procedure for the Synthesis of Acetylenic Sulfones from Arylacetylenic acids or
Arylacetylenes: To a solution of arylacetylenic acid or arylacetylene (0.5 mmol) with sodium
sulfinate (1 mmol), and iodine (0.25 mmol) in THF (2 mL) was added TBHP (70% in water, 1.5
mmol). The resulting mixture was stirred at room temperature for 16 h. The reaction mixture was
quenched by the addition of saturated aqueous Na2S2O3 (5 mL). Further stirring was followed by
extraction with EtOAc (2 × 20 mL). The combined organic extracts were washed with H2O (20
mL) and brine (20 mL), dried (MgSO4), filtered, and concentrated (aspirator). The residue was
purified by column chromatography using EtOAc/hexanes as eluent to afford the corresponding
product.
1ꢀMethylꢀ4ꢀ((phenylethynyl)sulfonyl)benzene (3a):13e pale yellow solid (110.2 mg, 86% yield
from 3ꢀphenylpropiolic acid; 71.8 mg, 56% yield from phenylacetylene); mp = 76–77 °C (from
1
CH2Cl2/hexanes) (lit.13e mp 74 °C); H NMR (400 MHz; CDCl3) δ 7.96 (d, J = 8.4 Hz, 2 H),
7.52–7.45 (m, 3 H), 7.40–7.34 (m, 4 H), 2.46 (s, 3 H) ppm; 13C NMR (100 MHz; CDCl3) δ 145.4
(C), 138.8 (C), 132.7 (2 × CH), 131.4 (CH), 130.0 (2 × CH), 128.6 (2 × CH), 127.4 (2 × CH),
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117.9 (C), 92.9 (C), 85.5 (C), 21.7 (CH3) ppm; IR (neat) ν 2179 (C≡C), 1322 and 1152 (SO2)
cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for C15H12O2SNa 279.0456, found 279.0469.
((Phenylethynyl)sulfonyl)benzene (3b):12i pale yellow solid (100.6 mg, 83% yield from 3ꢀ
phenylpropiolic acid; 65.4 mg, 54% yield from phenylacetylene); mp = 66–68 °C (from
CH2Cl2/hexanes) (lit.12i mp 62–63 °C); 1H NMR (400 MHz; CDCl3) δ 8.08 (d, J = 9.0 Hz, 2 H),
7.70–7.67 (m, 1 H), 7.62–7.58 (m, 2 H), 7.52–7.44 (m, 3 H), 7.36 (t, J = 7.6 Hz, 2 H) ppm; 13C
NMR (100 MHz; CDCl3) δ 141.8 (C), 134.1 (CH), 132.7 (2 × CH), 131.5 (CH), 129.3 (2 × CH),
128.7 (2 × CH), 127.3 (2 × CH), 117.8 (C), 93.5 (C), 85.3 (C) ppm; IR (neat) ν 2180 (C≡C),
1322 and 1154 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for C14H10O2SNa 265.0299,
found 265.0294.
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1ꢀMethoxyꢀ4ꢀ((phenylethynyl)sulfonyl)benzene (3c):13e pale yellow solid (83.1 mg, 61% yield
from 3ꢀphenylpropiolic acid; 61.3 mg, 45% yield from phenylacetylene); mp = 77−78 °C (from
1
CH2Cl2/hexanes) (lit.13e mp 77 °C); H NMR (400 MHz; CDCl3) δ 8.00 (d, J = 8.9 Hz, 2 H),
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7.51–7.44 (m, 3 H), 7.36 (t, J = 7.6 Hz, 2 H), 7.05 (d, J = 8.9 Hz, 2 H), 3.89 (s, 3H) ppm; C
NMR (100 MHz; CDCl3) δ 164.1 (C), 133.2 (C), 132.5 (2 × CH), 131.3 (CH), 129.7 (2 × CH),
128.6 (2 × CH), 117.9 (C), 114.5 (2 × CH), 92.4 (C), 85.8 (C), 55.7 (CH3) ppm; IR (neat) ν 2182
(C≡C), 1328 and 1149 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for C15H12O3SNa
295.0405, found 295.0410.
1ꢀChloroꢀ4ꢀ((phenylethynyl)sulfonyl)benzene (3d):12j pale yellow solid (113.5 mg, 82% yield
from 3ꢀphenylpropiolic acid; 63.7 mg, 46% yield from phenylacetylene); mp = 97−100 °C (from
1
CH2Cl2/hexanes); H NMR (400 MHz; CDCl3) δ 8.02 (d, J = 8.7 Hz, 2 H), 7.59–7.47 (m, 5 H),
13
7.38 (t, J = 7.6 Hz, 2 H) ppm; C NMR (100 MHz; CDCl3) δ 141.0 (C), 140.2 (C), 132.8 (2 ×
CH), 131.7 (CH), 129.7 (2 × CH), 128.9 (2 × CH), 128.7 (2 × CH), 117.6 (C), 94.0 (C), 85.0 (C)
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ppm; IR (neat) ν 2180 (C≡C), 1323 and 1149 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+
calcd for C14H9ClO2SNa 298.9909, found 298.9910.
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1ꢀBromoꢀ4ꢀ((phenylethynyl)sulfonyl)benzene (3e): white solid (46.6 mg, 29% yield from 3ꢀ
phenylpropiolic acid; 27.3 mg, 17% yield from phenylacetylene); mp = 98−100 °C (from
CH2Cl2/hexanes); 1H NMR (400 MHz; CDCl3) δ 7.96–7.92 (m, 2 H), 7.76–7.72 (m, 2 H), 7.54–
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7.47 (m, 3 H), 7.40–7.36 (m, 2 H) ppm; C NMR (100 MHz; CDCl3) δ 140.8 (C), 132.8 (2 ×
CH), 132.7 (2 × CH), 131.7 (CH), 129.6 (C), 128.9 (2 × CH), 128.7 (2 × CH), 117.6 (C), 94.0
(C), 85.0 (C) ppm; IR (neat) ν 2179 (C≡C), 1326 and 1151 (SO2) cm−1; HRMS (ESIꢀTOF) m/z
[M + Na]+ calcd for C14H9BrO2SNa 342.9404, found 342.9418.
((Methylsulfonyl)ethynyl)benzene (3f):12h yellow liquid (18.0 mg, 20% yield from 3ꢀ
1
phenylpropiolic acid); H NMR (400 MHz; CDCl3) δ 7.59–7.57 (m, 2 H), 7.51 (t, J = 7.5 Hz, 1
13
H), 7.41 (t, J = 7.6 Hz, 2 H), 3.30 (s, 3H) ppm; C NMR (100 MHz; CDCl3) δ 132.8 (2 × CH),
131.7 (CH), 128.7 (2 × CH), 117.4 (C), 91.4 (C), 84.4 (C), 46.7 (CH3) ppm; IR (neat) ν 2180
(C≡C), 1316 and 1139 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for C9H8O2SNa
203.0143, found 203.0142.
1ꢀMethylꢀ4ꢀ((pꢀtolylethynyl)sulfonyl)benzene (3g):13b pale yellow solid (121.6 mg, 90% yield
from 3ꢀ(pꢀtolyl)propiolic acid; 91.9 mg, 68% yield from 1ꢀethynylꢀ4ꢀmethylbenzene); mp =
101−103 °C (from CH2Cl2/hexanes) (lit.13b mp 100–101 °C); 1H NMR (400 MHz; CDCl3) δ 7.95
(d, J = 8.2 Hz, 2 H), 7.40–7.37 (m, 4 H), 7.16 (d, J = 7.9 Hz, 2 H), 2.45 (s, 3 H), 2.35 (s, 3 H)
ppm; 13C NMR (100 MHz; CDCl3) δ 145.2 (C), 142.2 (C), 139.0 (C), 132.5 (2 × CH), 129.9 (2 ×
CH), 129.3 (2 × CH), 127.3 (2 × CH), 114.7 (C), 93.6 (C), 85.1 (C), 21.6 (CH3), 21.5 (CH3)
ppm; IR (neat) ν 2176 (C≡C), 1327 and 1154 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+
calcd for C16H14O2SNa 293.0612, found 293.0616.
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1ꢀMethoxyꢀ4ꢀ((pꢀtolylethynyl)sulfonyl)benzene (3h):13b yellow amorphous solid (114.5 mg,
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methoxybenzene); mp = 77−79 °C (from CH2Cl2/hexanes); H NMR (400 MHz; CDCl3) δ 7.95
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(d, J = 8.3 Hz, 2 H), 7.45 (d, J = 8.9 Hz, 2 H), 7.38 (d, J = 8.1 Hz, 2 H), 6.86 (d, J = 8.9 Hz, 2 H),
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3.82 (s, 3H), 2.46 (s, 3H) ppm; C NMR (100 MHz; CDCl3) δ 162.1 (C), 145.1 (C), 139.2 (C),
134.6 (2 × CH), 129.9 (2 × CH), 127.3 (2 × CH), 114.4 (2 × CH), 109.5 (C), 94.1 (C), 84.8 (C),
55.4 (CH3), 21.6 (CH3) ppm; IR (neat) ν 2169 (C≡C), 1324 and 1151 (SO2) cm−1; HRMS (ESIꢀ
TOF) m/z [M + Na]+ calcd for C16H14O3SNa 309.0561, found 309.0554.
1ꢀMethylꢀ4ꢀ(((4ꢀtrifluoromethyl)phenyl)ethynyl)sulfonyl)benzene (3i):12c pale yellow solid
(110.3 mg, 68% yield from 3ꢀ(4ꢀ(trifluoromethyl)phenyl)propiolic acid); mp = 112−113 °C
1
(from CH2Cl2/hexanes); H NMR (400 MHz; CDCl3) δ 7.96 (d, J = 8.3 Hz, 2 H), 7.63 (s, 4 H),
13
7.41 (d, J = 8.2 Hz, 2 H), 2.47 (s, 3 H) ppm; C NMR (100 MHz; CDCl3) δ 145.8 (C), 138.4
(C), 133.0 (2 × CH), 132.9 (q, J = 33 Hz, C), 130.1 (2 × CH), 127.6 (2 × CH), 125.6 (q, J = 3 Hz,
2 × CH), 123.3 (q, J = 271.0 Hz, C), 121.8 (C), 90.3 (C), 87.3 (C), 21.7 (CH3) ppm; IR (neat) ν
2188 (C≡C), 1319 and 1155 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for
C16H11F3O2SNa 347.0330, found 347.0331.
1ꢀFluoroꢀ4ꢀ(tosylethynyl)benzene (3j):12e pale yellow solid (64.5 mg, 47% yield from 3ꢀ(4ꢀ
fluorophenyl)propiolic acid; 75.4 mg, 55% yield from 1ꢀethynylꢀ4ꢀfluorobenzene); mp = 75−77
°C (from CH2Cl2/hexanes); 1H NMR (400 MHz; CDCl3) δ 7.94 (d, J = 8.2 Hz, 2 H), 7.51 (dd, J
13
= 8.7, 5.4 Hz, 2 H), 7.39 (d, J = 8.0 Hz, 2 H), 7.06 (t, J = 8.6 Hz, 2 H), 2.46 (s, 3 H) ppm; C
NMR (100 MHz; CDCl3) δ 164.2 (d, J = 253 Hz, C), 145.4 (C), 138.8 (C), 135.0 (d, J = 9 Hz, 2
× CH), 130.0 (2 × CH), 128.7 (d, J = 198 Hz, C), 127.4 (2 × CH), 116.3 (d, J = 23 Hz, 2 × CH),
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91.8 (C), 85.5 (C), 21.7 (CH3) ppm; IR (neat) ν 2179 (C≡C), 1330 and 1151 (SO2) cm−1; HRMS
(ESIꢀTOF) m/z [M + Na]+ calcd for C15H11FO2SNa 297.0361, found 297.0365.
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1ꢀBromoꢀ4ꢀ(tosylethynyl)benzene (3k):13c white solid (134.1 mg, 80% yield from 3ꢀ(4ꢀ
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bromophenyl)propiolic acid); mp = 107−108 °C (from CH2Cl2/hexanes); H NMR (400 MHz;
CDCl3) δ 7.95 (d, J = 8.4 Hz, 2 H), 7.52 (d, J = 8.5 Hz, 2 H), 7.41–7.36 (m, 4 H), 2.47 (s, 3 H)
ppm; 13C NMR (100 MHz; CDCl3) δ 145.6 (C), 138.7 (C), 133.9 (2 × CH), 132.1 (2 × CH),
130.0 (2 × CH), 127.6 (2 × CH), 126.4 (C), 116.9 (C), 91.5 (C), 86.6 (C), 21.7 (CH3) ppm; IR
(neat) ν 2179 (C≡C), 1330 and 1156 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for
C15H11BrO2SNa 356.9561, found 356.9570.
1ꢀMethylꢀ4ꢀ(((4ꢀnitrophenyl)ethynyl)sulfonyl)benzene (3l):13a pale yellow solid (48.2 mg, 32%
yield from 3ꢀ(4ꢀnitrophenyl)propiolic acid); mp = 164−165 °C (from CH2Cl2/hexanes) (lit.13a mp
166–167 °C); 1H NMR (400 MHz; CDCl3) δ 8.23 (d, J = 8.8 Hz, 2 H), 7.96 (d, J = 8.3 Hz, 2 H),
13
7.69 (d, J = 8.8 Hz, 2 H), 7.42 (d, J = 8.1 Hz, 2 H), 2.48 (s, 3 H) ppm; C NMR (100 MHz;
CDCl3) δ 148.9 (C), 146.1 (C), 138.1 (C), 133.6 (2 × CH), 130.2 (2 × CH), 127.7 (2 × CH),
124.5 (C), 123.8 (2 × CH), 89.2 (C), 89.1 (C), 21.8 (CH3) ppm; IR (neat) ν 2181 (C≡C), 1337
and 1155 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for C15H11NO4SNa 324.0306,
found 324.0308.
1ꢀMethylꢀ3ꢀ(tosylethynyl)benzene (3m): pale yellow solid (121.6 mg, 90% yield from 3ꢀ(mꢀ
1
tolyl)propiolic acid); mp = 77−78 °C (from CH2Cl2/hexanes); H NMR (400 MHz; CDCl3) δ
7.95 (d, J = 8.3 Hz, 2 H), 7.39 (d, J = 8.3 Hz, 2 H), 7.33–7.24 (m, 4 H), 2.46 (s, 3 H), 2.32 (s, 3
H) ppm; 13C NMR (100 MHz; CDCl3) δ 145.3 (C), 139.0 (C), 138.5 (C), 133.1 (CH), 132.4
(CH), 129.9 (2 × CH), 129.8 (CH), 128.5 (CH), 127.4 (2 × CH), 117.7 (C), 93.3 (C), 85.3 (C),
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21.7 (CH3), 21.0 (CH3) ppm; IR (neat) ν 2160 (C≡C), 1334 and 1159 (SO2) cm−1; HRMS (ESIꢀ
TOF) m/z [M + Na]+ calcd for C16H14O2SNa 293.0612, found 293.0605.
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1ꢀChloroꢀ3ꢀ(tosylethynyl)benzene (3n): pale yellow solid (83.9 mg, 69% yield from 3ꢀ(3ꢀ
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chlorophenyl)propiolic acid); mp = 108−110 °C (from CH2Cl2/hexanes); H NMR (400 MHz;
CDCl3) δ 7.86 (d, J = 8.3 Hz, 2 H), 7.38–7.30 (m, 5 H), 7.22 (t, J = 7.9 Hz, 1 H), 2.38 (s, 3 H)
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ppm; C NMR (100 MHz; CDCl3) δ 145.6 (C), 138.5 (C), 134.5 (C), 132.2 (CH), 131.7 (CH),
130.7 (CH), 130.0 (2 × CH), 129.9 (CH), 127.5 (2 × CH), 119.6 (C), 90.7 (C), 86.4 (C), 21.7
(CH3) ppm; IR (neat) ν 2182 (C≡C), 1336 and 1163 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M +
Na]+ calcd for C15H11ClO2SNa 313.0066, found 313.0073.
1ꢀBromoꢀ2ꢀ(tosylethynyl)benzene (3o): pale yellow solid (58.7 mg, 35% yield from 3ꢀ(2ꢀ
bromophenyl)propiolic acid; 82.1 mg, 49% yield from 1ꢀbromoꢀ2ꢀethynylbenzene); mp = 50−52
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°C (from CH2Cl2/hexanes); H NMR (400 MHz; CDCl3) δ 7.98 (d, J = 8.3 Hz, 2 H), 7.59–7.57
(m, 1 H), 7.51–7.49 (m, 1 H), 7.39 (d, J = 8.1 Hz, 2 H), 7.33–7.28 (m, 2 H), 2.47 (s, 3 H) ppm;
13C NMR (100 MHz; CDCl3) δ 145.5 (C), 138.7 (C), 134.3 (CH), 132.8 (C), 132.4 (CH), 129.9
(2 × CH), 127.4 (2 × CH), 127.2 (CH), 126.4 (C), 120.6 (C), 90.9 (C), 89.0 (C), 21.7 (CH3) ppm;
IR (neat) ν 2182 (C≡C), 1329 and 1152 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for
C15H11BrO2SNa 356.9561, found 356.9558.
4ꢀMethoxyꢀ2ꢀmethylꢀ1ꢀ(tosylethynyl)benzene (3p): amorphous solid (100.6 mg, 67% yield
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from 3ꢀ(4ꢀmethoxyꢀ2ꢀmethylphenyl)propiolic acid); H NMR (400 MHz; CDCl3) δ 7.94 (d, J =
8.2 Hz, 2 H), 7.39–7.35 (m, 3 H), 6.71–6.67 (m, 2 H), 3.79 (s, 3 H), 2.45 (s, 3 H), 2.34 (s, 3 H)
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ppm; C NMR (100 MHz; CDCl3) δ 162.0 (C), 145.0 (C), 144.6 (C), 139.5 (C), 134.7 (CH),
129.8 (2 × CH), 127.1 (2 × CH), 115.4 (CH), 111.8 (CH), 109.6 (C), 93.8 (C), 88.4 (C), 55.3
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(CH3), 21.6 (CH3), 20.6 (CH3) ppm; IR (neat) ν 2161 (C≡C), 1321 and 1152 (SO2) cm−1; HRMS
(ESIꢀTOF) m/z [M + Na]+ calcd for C17H16O3SNa 323.0718, found 323.0717.
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2,4ꢀDimethoxyꢀ1ꢀ(tosylethynyl)benzene (3q): yellow liquid (262.6 mg, 83% yield from 3ꢀ(2,4ꢀ
dimethoxyphenyl)propiolic acid); 1H NMR (400 MHz; CDCl3) δ 7.93 (d, J = 8.2 Hz, 2 H), 7.35–
7.32 (m, 3 H), 6.42 (dd, J = 8.6, 2.0 Hz, 1 H), 6.36 (d, J = 1.6 Hz, 1 H), 3.80 (s, 3 H), 3.79 (s, 3
H), 2.43 (s, 3 H) ppm; 13C NMR (100 MHz; CDCl3) δ 163.9 (C), 163.3 (C), 144.7 (C), 139.6 (C),
135.6 (CH), 129.7 (2 × CH), 127.1 (2 × CH), 105.6 (CH), 99.4 (C), 98.1 (CH), 92.3 (C), 88.2
(C), 55.7 (CH3), 55.5 (CH3), 21.6 (CH3) ppm; IR (neat) ν 2161 (C≡C), 1321 and 1151 (SO2)
cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for C17H16O4SNa 339.0667, found 339.0663.
2ꢀ(Tosylethynyl)naphthalene (3r): pale yellow solid (81.2 mg, 53% yield from 3ꢀ(naphthalenꢀ
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2ꢀyl)propiolic acid); mp = 132−134 °C (from CH2Cl2/hexanes); H NMR (400 MHz; CDCl3) δ
8.07 (s, 1 H), 8.00 (d, J = 8.2 Hz, 2 H), 7.82–7.78 (m, 3 H), 7.58–7.51 (m, 2 H), 7.47 (d, J = 8.5
Hz, 1 H), 7.40 (d, J = 8.0 Hz, 2 H), 2.46 (s, 3 H) ppm; 13C NMR (100 MHz; CDCl3) δ 145.3 (C),
138.9 (C), 134.2 (CH), 134.0 (C), 132.3 (C), 130.0 (2 × CH), 128.5 (CH), 128.3 (CH), 128.1
(CH), 127.8 (CH), 127.4 (2 × CH), 127.3 (CH), 127.2 (CH), 115.0 (C), 93.4 (C), 85.7 (C), 21.7
(CH3) ppm; IR (neat) ν 2181 (C≡C), 1334 and 1161 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M +
Na]+ calcd for C19H14O2SNa 329.0612, found 329.0609.
2ꢀ(Tosylethynyl)thiophene (3s): yellow solid (82.6 mg, 63% yield from 3ꢀ(thiophenꢀ2ꢀ
1
yl)propiolic acid); mp = 87−88 °C (from CH2Cl2/hexanes); H NMR (400 MHz; CDCl3) δ 7.93
(d, J = 8.3 Hz, 2 H), 7.49 (dd, J = 5.0, 1.0 Hz, 1 H), 7.44 (dd, J = 3.7, 1.0 Hz, 1 H), 7.38 (d, J =
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8.0 Hz, 2 H), 7.03 (dd, J = 5.0, 3.8 Hz, 1 H), 2.45 (s, 3 H) ppm; C NMR (100 MHz; CDCl3) δ
145.4 (C), 138.7 (C), 137.0 (CH), 132.1 (CH), 130.0 (2 × CH), 127.6 (CH), 127.4 (2 × CH),
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117.3 (C), 89.1 (C), 87.1 (C), 21.7 (CH3) ppm; IR (neat) ν 2157 (C≡C), 1330 and 1159 (SO2)
cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for C13H10O2S2Na 285.0020, found 285.0024.
1ꢀFluoroꢀ3ꢀ(tosylethynyl)benzene (3t): white solid (57.6 mg, 42% yield from 1ꢀethynylꢀ3ꢀ
fluorobenzene); mp = 88−90 °C (from CH2Cl2/hexanes); 1H NMR (400 MHz; CDCl3) δ 7.96 (d,
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J = 8.2 Hz, 2 H), 7.42–7.27 (m, 4 H), 7.21–7.16 (m, 2 H), 2.47 (s, 3 H) ppm; C NMR (100
MHz; CDCl3) δ 162.0 (d, J = 247 Hz, C), 145.6 (C), 138.6 (C), 130.5 (d, J = 8 Hz, CH), 130.0 (2
× CH), 128.6 (d, J = 3 Hz, CH), 127.5 (2 × CH), 119.7 (d, J = 9 Hz, C), 119.3 (d, J = 24 Hz,
CH), 118.9 (d, J = 21 Hz, CH), 90.9 (d, J = 4 Hz, C), 86.1 (C), 21.7 (CH3) ppm; IR (neat) ν 2175
(C≡C), 1333 and 1152 (SO2) cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for C15H11FO2SNa
297.0361, found 297.0369.
Synthesis of (E)ꢀ1ꢀ((2ꢀIodoꢀ2ꢀphenylvinyl)sulfonyl)ꢀ4ꢀmethylbenzene (6a):14a A solution of
phenylacetylene (5a) (50.1 mg, 0.5 mmol) with pꢀtoluenesulfonyliodide (282.1 mg, 1 mmol) in
THF (2 mL) was stirred at room temperature for 16 h. The reaction mixture was quenched by the
addition of saturated aqueous Na2S2O3 (5 mL). Further stirring was followed by extraction with
EtOAc (2 × 20 mL). The combined organic extracts were washed with H2O (20 mL) and brine
(20 mL), dried (MgSO4), filtered, and concentrated (aspirator). The residue was purified by
column chromatography using EtOAc/hexanes as eluent to afford 6a; white solid (167.4 mg,
83% yield); mp = 80−82 °C (from CH2Cl2/hexanes) (lit.14a mp 77–79 °C); H NMR (400 MHz;
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CDCl3) δ 7.45 (d, J = 8.4 Hz, 2 H), 7.36 (s, 1 H), 7.32–7.26 (m, 3 H), 7.24–7.21 (m, 2 H), 7.18
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(d, J = 8.0 Hz, 2 H), 2.38 (s, 3 H) ppm; C NMR (100 MHz; CDCl3) δ 114.5 (C), 141.2 (CH),
139.6 (C), 137.2 (C), 129.7 (CH), 129.6 (2 × CH), 127.9 (2 × CH), 127.8 (2 × CH), 127.6 (2 ×
CH), 114.1 (C), 21.6 (CH3) ppm; IR (neat) ν 3057, 2920, 1585, 1326, 1141, 1083 cm−1; HRMS
(ESIꢀTOF) m/z [M + Na]+ calcd for C15H13IO2SNa 406.9579, found 406.9583.
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General Procedure for the Synthesis of βꢀIodovinyl Sulfones from Terminal Aliphatic
Alkyne and Internal Alkynes: To a solution of alkyne (0.5 mmol) with sodium sulfinate (1
mmol) and iodine (0.25 mmol) in THF (2 mL) was added TBHP (70% in water, 1.5 mmol). The
resulting mixture was stirred at room temperature for 16 h. The reaction mixture was quenched
by the addition of saturated aqueous Na2S2O3 (5 mL). Further stirring was followed by extraction
with EtOAc (2 × 20 mL). The combined organic extracts were washed with H2O (20 mL) and
brine (20 mL), dried (MgSO4), filtered, and concentrated (aspirator). The residue was purified by
column chromatography using EtOAc/hexanes as eluent to afford the corresponding product.
(E)ꢀ1ꢀ((2ꢀIodooctꢀ1ꢀenꢀ1ꢀyl)sulfonyl)ꢀ4ꢀmethylbenzene (6b):14a colorless viscous liquid (42.8
mg, 26% yield); 1H NMR (400 MHz; CDCl3) δ 7.77 (d, J = 8.2 Hz, 2 H), 7.35 (d, J = 8.1 Hz, 2
H), 7.00 (s, 1 H), 3.00 (t, J = 7.4 Hz, 2 H), 2.44 (s, 3 H), 1.53–1.49 (m, 2 H), 1.32–1.25 (m, 6 H),
0.90–0.85 (m, 3 H) ppm; 13C NMR (100 MHz; CDCl3) δ 144.8 (C), 138.9 (CH), 138.1 (C), 130.0
(2 × CH), 127.5 (2 × CH), 125.7 (C), 39.9 (CH2), 31.5 (CH2), 29.8 (CH2), 28.1 (CH2), 22.4
(CH2), 21.6 (CH3), 14.0 (CH3) ppm; IR (neat): ν = 3044, 2956, 2929, 2858, 1597, 1456, 1379,
1322, 1303, 1147, 1086, 1018, 816, 768 cmꢀ1; HRMS (ESIꢀTOF): m/z calcd for C15H21IO2SNa
[M + Na]+: 415.0205; found: 415.0204.
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(E)ꢀ(1ꢀIodoꢀ2ꢀtosyletheneꢀ1,2ꢀdiyl)dibenzene (6c):18d white solid (43.4 mg, 19% yield); mp =
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191−193 °C (from CH2Cl2/hexanes) (lit.18d mp 192–193 °C); H NMR (400 MHz; CDCl3) δ
7.37–7.32 (m, 8 H), 7.26 (d, J = 8.2 Hz, 2 H), 7.18–7.16 (m, 2 H), 7.09 (d, J = 8.1 Hz, 2 H), 2.36
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(s, 3 H) ppm; C NMR (100 MHz; CDCl3) δ 149.1 (C), 144.2 (C), 142.5 (C), 139.3 (C), 136.7
(C), 130.3 (2 × CH), 129.2 (3 × CH), 129.0 (CH), 128.5 (2 × CH), 128.3 (2 × CH), 127.8 (2 ×
CH), 127.3 (2 × CH), 118.0 (C), 21.6 (CH3) ppm; IR (neat) ν 3053, 2922, 1619, 1596, 1318,
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1150, 1087 cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for C21H17IO2SNa 482.9892, found
482.9899.
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(E)ꢀ1ꢀ((1ꢀIodoꢀ1ꢀphenylpropꢀ1ꢀenꢀ2ꢀyl)sulfonyl)ꢀ4ꢀmethylbenzene (6d):18a white solid (49.3
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mg, 27% yield); mp = 128–129 °C (from CH2Cl2/hexanes) (lit.18a mp 133–135 °C); H NMR
(400 MHz; CDCl3) δ 7.39 (d, J = 8.3 Hz, 2 H), 7.24–7.22 (m, 3 H), 7.16 (d, J = 8.1 Hz, 2 H),
7.12–7.10 (m, 2 H), 2.51 (s, 3 H), 2.39 (s, 3 H) ppm; 13C NMR (100 MHz; CDCl3) δ 144.1 (C),
143.9 (C), 142.9 (C), 137.2 (C), 129.5 (2 × CH), 128.6 (CH), 127.7 (2 × CH), 127.6 (2 × CH),
127.5 (2 × CH), 115.7 (C), 27.0 (CH3), 21.6 (CH3) ppm; IR (neat) ν 3059, 2922, 1623, 1593,
1315, 1151, 1079 cm−1; HRMS (ESIꢀTOF) m/z [M + Na]+ calcd for C16H15IO2SNa 420.9735,
found 420.9738.
(E)ꢀ1ꢀ((5ꢀIodooctꢀ4ꢀenꢀ4ꢀyl)sulfonyl)ꢀ4ꢀmethylbenzene (6e): yellowish liquid (32.3 mg, 14%
yield); 1H NMR (400 MHz; CDCl3) δ 7.74 (d, J = 8.3 Hz, 2 H), 7.33 (d, J = 8.0 Hz, 2 H), 3.15–
3.11 (m, 2 H), 2.58–2.54 (m, 2 H), 2.44 (s, 3 H), 1.61–1.49 (m, 4 H), 0.94–0.88 (m, 6 H) ppm;
13C NMR (100 MHz; CDCl3) δ 143.7 (C), 143.4 (C), 137.6 (C), 128.8 (2 × CH), 126.8 (C), 126.3
(2 × CH), 44.0 (CH2), 41.4 (CH2), 22.8 (CH2), 20.8 (CH2), 20.6 (CH3), 13.0 (CH3), 11.9 (CH3)
ppm; IR (neat) ν 2960, 2929, 1594, 1461, 1314, 1151, 1081 cm−1; HRMS (ESIꢀTOF) m/z [M +
Na]+ calcd for C15H21IO2SNa 415.0205, found 415.0212.
Acknowledgement
We thank the Thailand Research Fund (BRG5850012), the Center of Excellence for Innovation
in Chemistry (PERCHꢀCIC), the Office of the Higher Education Commission, Mahidol
University under the National Research Universities Initiative. Student scholarships from
Science Achievement Scholarship of Thailand (to J.M.) and the Development and Promotion of
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Science and Technology Talent Project (DPST), the Institute for the Promotion of Teaching
Science and Technology (to P.K.) are also gratefully acknowledged.
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Supporting Information
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Copies of Hꢀ and CꢀNMR spectra for all acetylenic sulfones 3 presented in Tables 2‒4 and
βꢀiodovinyl sulfones 6. This material is available free of charge via the internet
http://pub.acs.org.
References
(1) For vinyl sulfones see: (a) Uttamchandani, M.; Liu, K.; Panicker, R. C.; Yao, S. Q. Chem.
Commun. 2007, 1518–1520. (b) Steert, K.; ElꢀSayed, I.; Van der Veken, P.; Krishtal, A.; Van
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