Hydration of aromatic terminal alkynes catalyzed by sulfonated condensed polynuclear aromatic (S-COPNA) resin in water

Article abstract of DOI:10.1016/j.tetlet.2017.01.072

Hydration of aromatic terminal alkynes in the presence of a catalytic amount of sulfonated condensed polynuclear aromatic (S-COPNA) resin in water gave the corresponding methyl ketones in good yields. On the other hand, aliphatic terminal alkynes did not react at all under the employed conditions. Chemoselective hydration of aromatic terminal alkyne in the presence of aliphatic terminal alkyne catalyzed by S-COPNA resin was carried out.

Full text of DOI:10.1016/j.tetlet.2017.01.072

Accepted Manuscript
Hydration of aromatic terminal alkynes catalyzed by sulfonated condensed pol-
ynuclear aromatic (S-COPNA) resin in water
Kiyoshi Tanemura, Tsuneo Suzuki
PII:
S0040-4039(17)30104-1
DOI:
http://dx.doi.org/10.1016/j.tetlet.2017.01.072
TETL 48575
Reference:
Tetrahedron Letters
To appear in:
Received Date:
Revised Date:
Accepted Date:
15 December 2016
16 January 2017
23 January 2017
Please cite this article as: Tanemura, K., Suzuki, T., Hydration of aromatic terminal alkynes catalyzed by sulfonated
condensed polynuclear aromatic (S-COPNA) resin in water, Tetrahedron Letters (2017), doi: http://dx.doi.org/
10.1016/j.tetlet.2017.01.072
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Graphical Abstract
To create your abstract, type over the instructions in the template box below.
Fonts or abstract dimensions should not be changed or altered.
Hydration of aromatic terminal alkynes
catalyzed by sulfonated condensed
polynuclear aromatic (S-COPNA) resin in
water
Leave this area blank for abstract info.
Kiyoshi Tanemura, Tsuneo Suzuki

1
Tetrahedron Letters
Hydration of aromatic terminal alkynes catalyzed by sulfonated condensed
polynuclear aromatic (S-COPNA) resin in water
Kiyoshi Tanemura , Tsuneo Suzuki
Chemical Laboratory, School of Life Dentistry at Niigata, Nippon Dental University, Hamaura-cho, Niigata 951-8580, Japan
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
Hydration of aromatic terminal alkynes in the presence of a catalytic amount of sulfonated
condensed polynuclear aromatic (S-COPNA) resin in water gave the corresponding methyl
ketones in good yields. On the other hand, aliphatic terminal alkynes did not react at all under
the employed conditions. Chemoselective hydration of aromatic terminal alkyne in the presence
of aliphatic terminal alkyne catalyzed by S-COPNA resin was carried out.
Available online
2009 Elsevier Ltd. All rights reserved.
Keywords:
Hydration
Alkynes
Water
Ketones
Solid acids
Acid catalysts
The hydration of alkynes is a synthetically useful and atom
economical method for the synthesis of ketones.1 This
transformation is of great importance in industrial purposes as
well as in laboratory use. The traditional procedure using a
catalytic amount of mercury salts has been known.2,3 In order to
avoid the use of highly toxic mercury salts, many metal catalysts
such as Au,4-6 Ag,7-9 Pt,10,11 Ru,12 Pd,13 Fe,14,15 Co,16 and Ga17
have been devised. As the method using a Brønsted acid, H2SO4-
mediated reaction has been reported.18,19 However, this method
requires large amounts (> 1500 equiv) of H2SO4.20 Although the
reactions catalyzed by super acids such as TfOH,20 Tf2NH,20 and
Nafion NR5021 have been reported, these reagents are
considerably acidic and expensive. Recently, gallic acid/tannic
acid-catalyzed hydration has been devised.22
Organic transformations catalyzed by hydrophobic polymers
in water without the use of harmful organic solvents have been
paid for much attention since water is an easily available, safe,
economical, and environmentally friendly solvent.23,24 In
addition, organic reactions using polymers are of great interest
because they realize easy work-up and recycling of the catalysts.
During the course of our investigations on sulfonated
condensed polynuclear aromatic (S-COPNA) resins25,26 and
sulfonated polyarenes,27,28 we found that S-COPNA (NP) resin
(NP = naphthalene) is the quite useful catalyst for the hydration
of aromatic terminal alkynes in water. In this paper, we report the
results for the transformation of various alkynes catalyzed by S-
COPNA (NP) resin in water.
PPR) at reflux temperature for 16 h in various solvents. The
results are shown in Table 1. In dioxane-H2O (1 : 1) which
formed a homogeneous phase, the reactions proceeded more
slowly than those in the other biphasic media such as toluene-
H2O and heptane-H2O in both cases of S-COPNA (PR) resin and
S-PPR (entries 2-6).29 Interestingly, S-COPNA (PR)-catalyzed
reaction in water completed within
5 h to give 4-
methylacetophenone (23) in good yield (entry 1).
Table 1
Acid-catalyzed hydration of alkyne 3 in various solventsa
Yield (%)b
Entry
Solvent
S-COPNA (PR)
S-PPR
1
2
3
4
5
6
H2O
81c
54
72
37
13
80
82
81
84
Dioxane - H2O (1:1)
nBu2O - H2O (1:1)
CHCl2CHCl2 - H2O (1:1) 80
Toluene - H2O (1:1)
82
72
Heptane - H2O (1:1)
a Alkyne 3 (2.0 mmol), catalyst (0.2 mmol), solvent (4 mL), reflux (bath temp.
120 °C), 16 h, 600 rpm.
b Isolated yield.
c 5 h.
Next, Table 2 summarizes the results for various sulfonated
polymers and monomeric Brønsted acids in water. S-COPNA
resins were more active than the other sulfonated polymers and
monomeric Brønsted acids (entries 1 and 2). The low yields of S-
PPR and sulfonated polynaphthalene (S-PNP) would be
First, we examined the hydration of 4-ethynyltoluene (3) in
the presence of a catalytic amount of highly hydrophobic S-
COPNA (PR) resin (PR = pyrene) or sulfonated polypyrene (S-
———
 Corresponding author. Fax: +81 25 267 1134; E-mail address: tanemura@ngt.ndu.ac.jp (K. Tanemura).

2
Tetrahedron
attributed to the considerably high hydrophobic nature of these
polymers which were separated from the reaction mixture to
attach at the neck of the flask during the reactions. Although
Dowex 50WX8 resin worked most efficiently in the employed
commercially available sulfonated polymers, it required 60 h to
complete the reaction (entry 6). It is noteworthy that the
employed sulfonated polymers except S-PPR and S-PNP were
superior to monomeric Brønsted acids in water. Although S-
COPNA (PR) resin was the most active catalyst, it gradually
decomposed and was completely inactive on the fourth recycling
(Table 3, entry 1). The elemental analysis of the recovered S-
COPNA (PR) resin after the fourth use was C1.000H0.745O0.163S0.012
[S-COPNA (PR) resin: C1.000H0.725O0.396S0.088]. The acid density of
S-COPNA (PR) resin decreased from 4.02 to 0.76 mmol·g-1,
indicating the removal of the sulfo group. The IR spectra showed
the desulfonation16 from aromatic rings of S-COPNA (PR) resin.
The intensity of the characteristic absorptions at 1168 and 1029
cm-1 assigned to OH vibration of the sulfo groups largely
decreased and the absorptions due to the phenolic OH groups did
not appear. Although S-COPNA (NP) resin is less active than S-
COPNA (PR) resin, it did not lose the activity after the fifth
recycling (Table 3, entry 2).
Table 2
Hydration of alkyne 3 catalyzed by various acids in watera
Entry
Catalyst
Acid density (mmol∙g-1)
Yield (%)b
1
S-COPNA (PR)
S-COPNA (NP)
S-PPR
4.02
3.42
2.25
2.05
4.8
4.8
0.9
-
81c
2
84 (51)d (35)e
3
30
4
S-PNP
22
5
Amberlyst 15
Dowex 50WX8
Nafion NR50
H2SO4
43
59 (80)f
6
7
51
8
6
9
TsOH
-
16
10
11
TfOH
-
10
C8F17SO3H
-
32
a
Alkyne 3 (2.0 mmol), catalyst (0.2 mmol H+), H2O (4 mL), reflux (bath
temp. 120 °C), 8 h, 600 rpm.
b Isolated yield.
c 5 h.
d In dioxane – H2O (1 : 1) (4 mL).
e In toluene – H2O (1 : 1) (4 mL).
f 60 h.
Table 3
Recycle experiments for the hydration of alkyne 3
Yield (%)a
Entry
Catalyst
1st
2nd
3rd
4th
5th
1b
2c
S-COPNA (PR) 81
S-COPNA (NP) 82
41
82
16
84
0
0
80
80
a Isolated yield.
b Alkyne 3 (2.0 mmol), S-COPNA (PR) (0.2 mmol), H2O (4 mL), reflux (bath
temp. 120 °C), 5 h, 600 rpm.
c Alkyne 3 (2.0 mmol), S-COPNA (NP) (0.2 mmol), H2O (4 mL), reflux (bath
temp. 120 °C), 8 h, 600 rpm.
Table 4 shows the results for the reactions of a wide range of
alkynes catalyzed by S-COPNA (NP) resin in water. Aromatic
terminal alkynes except 8 were transformed to the corresponding
methyl ketones in good to excellent yields, respectively (entries

3
1-7 and 9). The hydration of 6 and 7 possessing electron-
withdrawing halogen groups in the phenyl moiety proceeded
slowly to afford 26 and 27 in good yields, respectively. The
presence of the strongly electron-withdrawing trifluoromethyl
group suppressed the reaction entirely (entry 8). ,-Unsaturated
alkyne 10 tolerated the reaction conditions without
decomposition to give 30 in excellent yield. Aryl trimethylsilyl
(TMS) acetylenes, which can be easily synthesized from
Sonogashira coupling,30,31 reacted to give the corresponding
methyl ketones more slowly than the unprotected alkynes via the
deprotection followed by hydration (entries 11 and 12).32 Further
utility of S-COPNA (NP) resin was explored on the reactions of
propargylic alcohols 13 and 14, which were converted into ,-
unsaturated ketones 30 and 31 via the dehydration followed by
the hydration of the alkyne, respectively (Rupe rearrangement).33
The reaction of internal alkyne, 1-phenyl-1-propyne (15)
underwent quite slowly to afford carbonyl compound 32. No
reaction occurred with aromatic internal alkyne 16 and aliphatic
internal alkyne 17. It is noteworthy that aliphatic terminal
alkynes 18-20 were inert under the employed conditions.
which resulted in the exclusive reaction of aromatic terminal
alkyne in the presence of aliphatic terminal alkyne.
Table 5 summarizes the results for the competitive hydration
between aromatic terminal alkyne 3 and aliphatic terminal alkyne
18 promoted by metal catalysts and Brønsted acids. In the cases
of examined metal-catalyzed reactions, both compounds 23 and
35 were obtained in moderate to good yields (entries 1-6).
Because the rates of the hydration of 3 and 18 did not have large
differences, it was difficult to obtain 23 in good yields without
the production of 35. Exclusive hydration of 3 was observed
when super acids as well as S-COPNA (NP) resin were employed
as the catalysts (entries 7-10). It was found to be a general
tendency of Brønsted acid catalysis. The hydration catalyzed by
Nafion NR50 in AcOH progressed faster than that in water
(Table 2, entry 7 and Table 5, entry 9), but a large amount of
alkaline solution is required to remove AcOH on work-up. It
should be noted that S-COPNA (NP) resin realized the
chemoselective hydration of 3 in the presence of 18 which was
difficult to carry out by the metal catalysts (entry 10).
Table 5
Based on the difference in reactivities between aromatic
terminal alkynes and aromatic internal alkynes, we explored the
chemoselective hydration of 4 and 5. Aromatic terminal alkyne
was hydrated exclusively in the presence of aromatic internal
alkyne to give the corresponding methyl ketone in good yield
(Scheme 1). We also succeeded the chemoselective hydration of
aromatic terminal alkyne in the presence of aliphatic terminal
alkyne (Scheme 2). This is the first example as far as we know
Competitive hydration of alkynes 3 and 18 by various
catalysts
Yield (%)a
Entry
Catalyst
23
84
91
83
58
98
43
87
90
88
84
35
74
99
85
80
67
92
4
1b
2c
3d
4e
5f
6g
7h
8h
9i
HgSO4
AuCl
[(Ph3P)AuCH3]
AgSbF6
AgOTf
[PtCl2(C2H4)]2
Tf2NH
TfOH
0
Nafion NR50
S-COPNA (NP)
0
10j
0
a Isolated yield.
b
Alkyne 3 (2.0 mmol), Alkyne 18 (2.0 mmol), HgSO4 (0.11 mmol), H2O (1
mL), H2SO4 (0.04 mL), 90 °C, 12 h.
c
Alkyne 3 (2.0 mmol), Alkyne 18 (2.0 mmol), AuCl (0.1 mmol), MeOH (4
mL), H2O (8 mmol), 65 °C, 1 h, N2.
d
Alkyne 3 (10.0 mmol), Alkyne 18 (10.0 mmol), [(Ph3P)AuCH3] (0.01
mmol), MeOH (5 mL), H2O (0.5 mL), TfOH (0.25 mmol), 70 °C, 0.5 h.
e Alkyne 3 (2.0 mmol), Alkyne 18 (2.0 mmol), AgSbF6 (0.2 mmol), MeOH (3
mL), H2O (0.3 mL), 75 °C, 48 h.
f Alkyne 3 (2.0 mmol), Alkyne 18 (2.0 mmol), AgOTf (0.2 mmol), EtOAc (6
mL), H2O (0.4 mL), 80 °C, 48 h.
g
Alkyne 3 (2.0 mmol), Alkyne 18 (2.0 mmol), Zeise’s dimer (0.014 mmol),
THF (1.5 mL), H2O (6 mmol), 70 °C, 48 h.
h
Alkyne 3 (2.0 mmol), Alkyne 18 (2.0 mmol), Tf2NH or TfOH (0.2 mmol),
dioxane (4 mL), H2O (6 mmol), 100 °C, 5 h.
I
Alkyne 3 (5.0 mmol), Alkyne 18 (5.0 mmol), Nafion NR50 (167 mg, 0.15
mmol), AcOH (2 mL), H2O (15 mmol), 100 °C, 3 h.
j
Alkyne 3 (2.0 mmol), Alkyne 18 (2.0 mmol), S-COPNA (NP) (59 mg, 0.2
mmol), H2O (4 mL), 120 °C, 12 h.
In summary, we devised an environmentary benign method
for the hydration of aromatic terminal alkynes in water. It
constitutes a useful procedure for selective hydration of aromatic
terminal alkyne in the presence of aliphatic terminal alkyne. In
addition, it is noteworthy that (1) the work-up procedure is
remarkably simple because S-COPNA (NP) resin is a solid acid
and (2) S-COPNA (NP) resin can be reused without significant
loss of activity.
Acknowledgments

4
Tetrahedron
28. Tanemura, K.; Suzuki, T.; Horaguchi, T. J. Appl. Polym. Sci.
We thank the Division of Chemical Analysis, Systems
2013, 127, 4524-4536.
29. Komine, N.; Sako, A.; Hirahara, S.; Hirano, M.; Komiya, S.
Chem. Lett. 2005, 34, 246-247.
30. Sakamoto, T.; Kondo, Y.; Iwasawa, S.; Yamanaka, H. Chem.
Pharm. Bull. 1987, 35, 1823-1828.
Engineering for the elemental analyses. We thank the Research
Promotion Grant (NDU Grants N-16010) from Nippon Dental
University.
Supplementary data
31. Sonogashira, K.; Tohda, Y.; Hagihara, N. Tetrahedron Lett.
1975, 16, 4467-4470.
32. Hassam, M.; Li, W.-S. Tetrahedron 2015, 71, 2719-2723.
33. Olah, G. A.; Fung, A. P. Synthesis 1981, 1981, 473-474.
Supplementary data (general experimental procedures, data of
1
IR and H-NMR spectra of the products) associated with this
article can be found, in the online version.
References and notes
1. Alonso, F.; Beletskaya, I. P.; Yus, M. Chem. Rev. 2004, 104,
3079-3160.
2. Newman, M. S.; Reichle, W. R. Org. Synth. 1973, Coll. Vol. 5,
1024-1025.
3. Stacy, G. W.; Mikulec, R. A. Org. Synth. 1963, Coll. Vol. 4, 13-
15.
4. Das, A. K.; Park, S.; Muthaiah, S.; Hong, S. H. Synlett 2015, 26,
2517-2520.
5. Mizusawa, E.; Sato, K.; Hayashi, T.; Tanaka, M. Angew. Chem.
Int. Ed. 2002, 41, 4563-4565.
6. Xu, Y.; Hu, X.; Shao, J.; Yang, G.; Wu, Y.; Zhang, Z. Green
Chem. 2015, 17, 532-537.
7. Chen, Z.-W.; Ye, D.-N.; Qian, Y.-P.; Ye, M.; Liu, L.-X.
Tetrahedron 2013, 69, 6116-6120.
8. Das, R.; Chakraborty, D. Appl. Organomet. Chem. 2012, 26,
722.
9. Thuong, M. B.; Mann, A.; Wagner, A. Chem. Commun. 2012,
48, 434-436.
10. Hartman, J.; Hiscox, W.; Jennings, P. J. Org. Chem. 1993, 58,
7613-7614.
11. Hiscox, W.; Jennings, P. Organometallics 1990, 9, 1997-1999.
12. Tokunaga, M.; Wakatsuki, Y. Angew. Chem. Int. Ed. 1998, 37,
2867-2869.
13. Kadota, I.; Lutete, L. M.; Shibuya, A.; Yamamoto, Y.
Tetrahedron Lett. 2001, 42, 6207-6210.
14. Wu, X. -F.; Bezier, D.; Darcel, C. Adv. Synth. Catal. 2009, 351,
367-370.
15 Park, J.; Yeon, J.; Lee, P. H.; Lee, K. Tetrahedron Lett. 2013, 54,
4414-4417.
16. Tachinami, T.; Nishimura, T.; Ushimaru, R.; Noyori, R.; Naka,
H. J. Am. Chem. Soc. 2013, 135, 50-53.
17. Liang, S.; Hammond, G. B.; Xu, B. Chem. Commun. 2015, 51,
903-906.
18. Allen, A. D.; Chiang, Y.; Kresge, A. J.; Tidwell, T. T. J. Org.
Chem. 1982, 47, 775-779.
19. Smith Jr, J. M.; Stewart, H. W.; Roth, B.; Northey, E. H. J. Am.
Chem. Soc. 1948, 70, 3997-4000.
20. Tsuchimoto, T.; Joya, T.; Shirakawa, E.; Kawakami, Y. Synlett
2000, 1777-1778.
21. Liang, S.; Hammond, G. B.; Xu, B. Chem. Commun. 2015, 51,
903-906.
22. Deng, T.; Wang, C. -Z. Catal. Sci. Technol. 2016, 6, 7029-7032.
23. Kobayashi et al. have been conducting the pioneering work on
organic transformation in water. Alkyne 3 was hydrated in the
presence of 10 mol% of low-loading and alkylated polystyrene-
supported sulfonic acid (LL-ALPS-SO3H) in boiling water for 48
h to give 23 in 81% yield: Iimura, S.; Manabe, K.; Kobayashi, S.
Org. Biomol. Chem. 2003, 1, 2416-2418.
24. Iimura, S.; Manabe, K.; Kobayashi, S. Org. Lett. 2003, 5, 101-
103.
25. Tanemura, K.; Suzuki, T.; Nishida, Y.; Horaguchi, T.
Tetrahedron 2011, 67, 1314-1319.
26. Tanemura, K.; Suzuki, T.; Nishida, Y.; Horaguchi, T. Polym.
Bull. 2012, 68, 705-719.
27. Tanemura, K.; Suzuki, T. Tetrahedron Lett. 2013, 54, 1972-
1975.

5
* Hydration of aromatic terminal alkyne in the
presence of aliphatic terminal alkyne.
* The solvent is environmentally friendly water.
* The work-up procedure is remarkably simple.
* The catalyst can be recycled without significant
loss of activity.