TTMPP-catalyzed addition of alkynes using trimethylsilylacetylenes

Article abstract of DOI:10.1080/00397910802585878

A highly basic phosphine, tris(2,4,6-trimethoxyphenyl)phosphine (TTMPP), catalyzes alkynylation using trimethylsilylalkyne to give the corresponding products in good to high yields. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/00397910802585878

This article was downloaded by: [The University Of Melbourne Libraries]
On: 05 June 2013, At: 07:37
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954
Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,
UK
Synthetic Communications: An
International Journal for Rapid
Communication of Synthetic
Organic Chemistry
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/lsyc20
TTMPP-Catalyzed
Addition of Alkynes Using
Trimethylsilylacetylenes
S. Matsukawa a & I. Sekine a
a Faculty of Education, Department of Science
Education, Ibaraki University, Mito, Ibaraki, Japan
Published online: 15 Apr 2009.
To cite this article: S. Matsukawa & I. Sekine (2009): TTMPP-Catalyzed Addition of
Alkynes Using Trimethylsilylacetylenes, Synthetic Communications: An International
Journal for Rapid Communication of Synthetic Organic Chemistry, 39:10, 1718-1721
To link to this article: http://dx.doi.org/10.1080/00397910802585878
PLEASE SCROLL DOWN FOR ARTICLE
Full terms and conditions of use: http://www.tandfonline.com/page/terms-
and-conditions
This article may be used for research, teaching, and private study purposes.
Any substantial or systematic reproduction, redistribution, reselling, loan,
sub-licensing, systematic supply, or distribution in any form to anyone is
expressly forbidden.
The publisher does not give any warranty express or implied or make any
representation that the contents will be complete or accurate or up to
date. The accuracy of any instructions, formulae, and drug doses should be
independently verified with primary sources. The publisher shall not be liable

for any loss, actions, claims, proceedings, demand, or costs or damages
whatsoever or howsoever caused arising directly or indirectly in connection
with or arising out of the use of this material.

Synthetic Communications1, 39: 1718–1721, 2009
Copyright # Taylor & Francis Group, LLC
ISSN: 0039-7911 print=1532-2432 online
DOI: 10.1080/00397910802585878
TTMPP-Catalyzed Addition of Alkynes Using
Trimethylsilylacetylenes
S. Matsukawa and I. Sekine
Faculty of Education, Department of Science Education,
Ibaraki University, Mito, Ibaraki, Japan
Abstract: A highly basic phosphine, tris(2,4,6-trimethoxyphenyl)phosphine
(TTMPP), catalyzes alkynylation using trimethylsilylalkyne to give the corres-
ponding products in good to high yields.
Keywords: Alkynylation, base catalyst, organosilicon compounds
INTRODUCTION
Tris(2,4,6-trimethoxyphenyl)phosphine (TTMPP) is known as a highly
basic phosphine because of its multiple methoxy substitutions.[1] Many
unique reactions have been reported using TTMPP as an organocatalyst
by authors such as Yoshimoto, Kawabata, and Chuprakor.[2] We have
previously demonstrated that TTMPP catalyzes aldol and imine–aldol
reactions via O-Si bond activation[3] and also reported the catalytic
reaction via C-Si bond activation.[3] To apply the underlying mechanisms
to other useful reactions, catalytic alkynylation was examined.
Alkynylation of carbonyl compounds is one of the most important
carbon–carbon bond-forming reactions in organic synthesis. Although sev-
eral Lewis acid catalytic reactions are known, examples of base-catalyzed
alkynylation remain scarce.[4] We report herein the TTMPP-catalyzed
alkynylation of carbonyl compounds using trimethylsilylacetylenes.
Received August 11, 2008.
Address correspondence to S. Matsukawa, Faculty of Education, Department
of Science Education, Ibaraki University, Mito, Ibaraki 310-8512, Japan. E-mail:
smatsuka@mx.ibaraki.ac.jp
1718

TTMPP-Catalyzed Addition of Alkynes
RESULTS AND DISCUSSION
1719
Initially, alkynylation of benzaldehyde with 1-phenyl-2-(trimethylsilyl)-
acetylene was examined in the presence of 10 mol% TTMPP in dimethyl-
formamide (DMF) at room temperature. However, the reaction was very
slow. The reaction was then performed at elevated temperature. The
desired product was obtained in 95% yield in 8 h at 100ꢀC. The product
was obtained in low yield when other phosphines were used instead
of TTMPP. These results indicate that TTMPP effectively activates the
C-Si bond of 1-phenyl-2-(trimethylsilyl)acetylene.
To clarify the scope of this reaction, several aldehydes were examined
in the presence of 10 mol% TTMPP (Table 1). Good results were obtained
Table 1. TTMPP-catalyzed alkynylation of carbonyl compounds
Entry
R
Temperature (ꢀC)
Time (h)
Yield (%)
1
2
C6H5
rt
24
8
24
24
16
8
8
16
8
16
8
8
16
24
Trace
95
12
Trace
85
98
80
74
80
90
100
100
100
100
120
120
120
120
100
120
100
100
120
3a
4b
5
4-CH3OC6H4
4-ClC6H4
6
7
8
9
10
11
12
13
14c
4-NO2C6H4
1-Naphthyl
2-Naphthyl
(E)-PhCH¼CH
PhCH2CH2
n-C8H17
95
96
88
n.r.
c-C6H11
C6H5
aP(nBu)3 was used instead of TTMPP.
bPPh3 was used instead of TTMPP.
c1-Trimethylsilyl-1-hexyne was used instead of 1-phenyl-2-(trimethylsilyl)
acetylene.

1720
S. Matsukawa and I. Sekine
for aromatics having either electron-donating or electron-withdrawing
group aldehydes. 1,2-Adducts were obtained in good yields when
a,b-unsaturated aldehydes were employed. In addition, aliphatic alde-
hydes also worked well.
In summary, we demonstrated TTMPP-catalyzed alkynylation of
aldehydes using trimethylsilylacethylene. Although hotter temperatures
were needed, TTMPP effectively activated the C-Si bond of trimethylsi-
lylacethylene, and the reaction proceeded smoothly to afford the corre-
sponding product.
Representative Experimental Procedure
Aldehyde (0.5 mmol) and 1-phenyl-2-trimethylsilylacetylene (0.75 mmol)
were added to a solution of TTMPP (0.05 mmol) in DMF (1 mL) at
100ꢀC. After stirring for 8 h, the resultant mixture was quenched with
5% HCl-MeOH. The mixture was extracted with EtOAc, and the
organic layer was washed with brine, dried over anhydrous Na2SO4, and
evaporated. The crude mixture was purified by column chromatography
on silica gel (AcOEt–hexane ¼ 1:3) to give the corresponding product.
Selected Data
1,3-Diphenyl-2-propyn-1-ol
1H NMR (400 MHz, CDCl3) d 2.45 (br, 1H), 5.65 (s, 1H), 7.22–7.30
(m, 6H), 7.36 (m, 2H), 7.60 (m, 2H). 13C NMR (100 MHz, CDCl3) d
64.6, 84.2, 122.3, 126.6, 128.1, 131.6, 137.5, 140.5.
1-(40-Methoxyphenyl)-3-phenyl-2-propyn-1-ol
1H NMR (400 MHz, CDCl3) d 2.35 (br, 1H), 3.83 (s, 3H), 5.62 (s, 1H),
6.90 (d, J ¼ 8.0 Hz, 2H), 7.31 (m, 3H), 7.45 (d, J ¼ 8.0 Hz, 2H), 7.52
(d, J ¼ 8.0 Hz, 2H). 13C NMR (100 MHz, CDCl3) d 55.2, 64.6, 86.4,
113.9, 122.6, 128.2, 131.6, 133.0, 139.7.
1-Cyclohexyl-3-phenyl-2-propyn-1-ol
1H NMR (400 MHz, CDCl3) d 1.10–1.42 (m, 5H), 1.50–2.00 (m, 7H),
4.38 (m, 1H), 7.27–7.46 (m, 5H). 13C NMR (100 MHz, CDCl3) d 25.8,
26.3, 28.1, 28.5, 44.3, 67.5, 85.5, 89.3, 122.7, 128.1, 131.5.

TTMPP-Catalyzed Addition of Alkynes
REFERENCES
1721
1. Wada, M.; Higashizaki, S.
A
highly basic triphenylphosphine,
[2,4,6-(MeO)3C6H2]3P. J. Chem. Soc., Chem. Commun. 1984, 482–483.
2. (a) Yoshimoto, K.; Kawabata, H.; Nakamichi, N.; Hayashi, M. Tris(2,4,6-
trimethoxyphenyl)phosphine (TTMPP): A novel catalyst for selective deacety-
lation. Chem. Lett. 2001, 30, 934–935; (b) Kawabata, H.; Hayashi, M. Lewis
base-catalyzed transformation of a,b-unsaturated aldehydes to saturated
carboxylic acids, esters, and amides. Tetrahedron Lett. 2002, 43, 5645–5647;
(c) Weeden, J. A.; Chisfolm, J. D. Phosphine-catalyzed nitroaldol reactions.
Tetrahedron Lett. 2006, 47, 9313–9316; (d) Hirata, N.; Hayashi, M. Nitroaldol
reaction catalyzed by tris(2,4,6-trimethoxyphenyl)phosphine (TTMPP). Synth.
Commun. 2007, 37, 1653–1657; (e) Chuprakov, S.; Malyshev, D. A.; Trofimov,
A.; Gevorgyan, V. Sila Morita–Baylis–Hillman reaction of cyclopropenes.
J. Am. Chem. Soc. 2007, 129, 14868–14869.
3. (a) Matsukawa, S.; Okano, N.; Imamoto, T. Phosphine catalyzed aldol reac-
tion between ketene silyl acetals and aldehydes: Nucleophilic O–Si and C–Si
bond cleavage by phosphines. Tetrahedron Lett. 2000, 41, 103–107; (b)
Matsukawa, S.; Obu, K. TTMPP catalyzed one-pot silyl ketene acetal-imine
condensation route to b-lactams. Chem. Lett. 2004, 33, 1626–1627; (c)
Matsukawa, S.; Kitazaki, E. Catalytic cyanomethylation of carbonyl com-
pounds and imines with highly basic phosphine. Tetrahedron Lett. 2008, 49,
2982–2984; (d) Matsukawa, S.; Saijo, M. TTMPP-catalyzed trifluoromethyl-
ation of carbonyl compounds and imines with trifluoromethylsilane. Tetra-
hedron Lett. 2008, 49, 4855–4857.
4. (a) Nakamura, E.; Kuwajima, I. Fluoride-catalyzed addition of silylacetylenes
to carbonyl compounds. Angew. Chem., Int. Ed. Engl. 1976, 8, 498–499; (b)
Lettan, R. B. II; Scheidt, K. A. Lewis base-catalyzed additions of alkynes
using trialkoxysilylalkynes. Org. Lett. 2005, 7, 3227–3230; (c) Kitazawa, T.;
Minowa, T.; Mukaiyama, T. Lewis base-catalyzed alkynylation of carbonyl
compounds with trimethylsilylacetylenes. Chem. Lett. 2006, 35, 1002–1003.