Homo and hetero glaser coupling involving acetylene derivatives of trifluoromethanesulfonamide

Article abstract of DOI:10.1134/S1070428016020044

Glaser homocoupling of N,N-bispropargyltriflamide led to the formation of N,N′-hexa-2,4-diyne-1,6-diylbis(N-prop-2-yne-1-triflamide). Further condensation into a 14-membered heterocycle, 1,8-bis-(triflyl)-1,8-diazacyclotetradeca-3,5,10,12-tetrayne did not occur evidently because of rigid steric requirements to the cyclization. In the Glaser heterocoupling of N-propargyltriflamide with arylacetylenes ArC≡CH (Ar = Ph, p-CNC₆H₄) the condensation products formed in 20-30% yields.

Full text of DOI:10.1134/S1070428016020044

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2016, Vol. 52, No. 2, pp. 192–195. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © B.A. Shainyan, I.V. Ushakova, 2016, published in Zhurnal Organicheskoi Khimii, 2016, Vol. 52, No. 2, pp. 210–213.
Homo and Hetero Glaser Coupling Involving
Acetylene Derivatives of Trifluoromethanesulfonamide
B. A. Shainyan and I. V. Ushakova
Favorskii Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
е-mail: bagrat@irioch.irk.ru
Received December 3, 2015
Abstract—Glaser homocoupling of N,N-bispropargyltriflamide led to the formation of N,N'-hexa-2,4-diyne-
1,6-diylbis(N-prop-2-yne-1-triflamide). Further condensation into a 14-membered heterocycle, 1,8-bis-(triflyl)-
1,8-diazacyclotetradeca-3,5,10,12-tetrayne did not occur evidently because of rigid steric requirements to the
cyclization. In the Glaser heterocoupling of N-propargyltriflamide with arylacetylenes ArC≡CH (Ar = Ph, p-
CNC6H4) the condensation products formed in 20–30% yields.
DOI: 10.1134/S1070428016020044
Highly unsaturated trifluoromethanesulfonamide
(triflamide TfNH2) are interesting both due to their
electronic structure and from the viewpoint of their
synthetic potential as building blocks in the organic
synthesis. In particular, the derivatives possessing
terminal acetylene groups are able to undergo the
oxidative dimerization into the corresponding
diacetylenes that may be further used in
cyclocondensation reactions for the preparation of
diverse adducts and functionalized heterocycles. We
formerly demonstrated that N-propargyltriflamide 1 [1]
cleanly dimerized in oxidative conditions at room
temperature in water giving N,N'-hexa-2,4-diyne-1,6-
diylbis(triflamide) 2 [2] (Scheme 1).
acetylenes ArC≡CH [Ar = Ph (4), p-CNC6H4 (5), p-
NO2C6H4 (6)] (Glaser heterocoupling).
Although the oxidative acetylene dimerization is
well known [3], the successive achievement of both
mentioned reactions required the selection of special
conditions. For instance, unlike the easily dimerized N-
propargyltriflamide 1 [2], N,N-bispropargyltriflamide 3
[4] does not afford the product of condensation at
room temperature even at 4–5-fold longer reaction
time (up to 10 h). The reaction was achieved only after
prolonged heating to 70°С in the presence of 20 mol %
CuCl with a low preparative yield of N,N'-hexa-2,4-
diyne-1,6-diylbis(N-prop-2-yne-1-triflamide) 7 (20%)
isolated by column chromatography (Scheme 2).
Scheme 1.
Scheme 2.
CH2C CH
2 TfNHCH2C CH
1
TfN
[O], CuCl
_H2O
CH2C CH
TfNHCH2C
C
C
CCH2NHTf
3
2
DMSO
[O], CuCl
Tf = CF3SO2.
CH2C
CH2C
C
C
CH2C
CH2C
NTf
TfN
In continuation of these studies and in order to
expand the family of triflamide diacetylene derivatives
in the present work we have studied the oxidative
dimerization of N,N-bispropargyltriflamide 3 (Glaser
homo-coupling) and the possibility of cross
CH
HC
7
The reaction was accompanied with strong resini-
fication apparently due to the presence of terminal
dimerization of N-propargyltriflamide
1
with
192

HOMO AND HETERO GLASER COUPLING INVOLVING ACETYLENE DERIVATIVES
193
Scheme 3.
[O], CuCl
[O], CuCl
+
TfNHCH2C
C
CPh
1
PhC
CH
C
C
CPh
2 + PhC
C
H2O, 20oC
MeOH_H2O, Δ
8
4
9
_H2O
acetylene groups in compounds 3 and 7 that reduced
the yield of the target product. Unlike dimer 2 [2]
compound 7 is a liquid readily soluble in chloroform.
Its structure and composition are proved by IR and
NMR spectra and the data of elemental analysis, in
particular, by the presence in the 1Н NMR spectrum of
characteristic doublet and triplet signals of the terminal
propargyl group СН2С≡СН and of a singlet of the me-
thylene protons of the internal propargyl group
СН2С≡С–, and the appearance in the 13С NMR spec-
trum of two signals of the methylene groups and four
signals of nonequivalent acetylene carbon atoms in the
region 70–76 ppm, as well as of a quartet of the CF3
group. The IR spectrum contains the absorption bands of
vibrations ν(≡CH) at 3301 cm–1 and ν(C≡C) at 2131 cm–1
of weak intensity caused by the symmetric structure of
the linear fragment С–С≡C–С≡C–С in the molecule.
N-Propargyltriflamide 1, which practically quantita-
tively dimerizes under heterophase conditions at room
temperature as shown in reaction (1) does not enter
cross-coupling with phenylacetylene 4 under the same
conditions. Only homocondensation products were isola-
ted: diphenyldiacetylene PhC≡CC≡CPh 8 and dimer 2.
It is presumably due to the impeding by the strong
acceptor N-triflyl group the interaction of the copper
complex both with N-propargyltriflamide and phenyl-
acetylene, and therefore the cross-coupling requires more
stringent conditions. Cross-coupling 3 + 4 with the
formation of N-(5-phenylpenta-2,4-diyn-1-yl)-triflamide
9 in 30% yield was successfully carried out in the
presence of double excess of CuCl in aqueous methanol
at heating to 40°С no longer than 4 h (Scheme 3).
In the reaction of N-propargyltriflamide 1 with 4-
ethynylbenzonitrile 5 at 50°С in aqueous methanol only
dimer 2 and products of resinification of 4-ethynyl-
benzonitrile 5 were obtained. Cross-coupling 1 + 5
with the formation of N-[5-(4-cyanophenyl)penta-2,4-
diyne-1-yl]triflamide 10 in 20% yield was achieved in
DMSO at heating to 45°С for 8 h in the presence of
30% excess of CuCl (Scheme 4). The increase of the
CuCl concentration does not affect the yield of the
coupling product 10. At room temperature the reaction
does not occur, at raising the temperature to 55°С,
same as in aqueous methanol, only dimer 2 and
products of resinification of 4-ethynylbenzonitrile 5
were formed. At yet higher temperature (up to 70°С)
resinification occurs both with N-propargyltriflamide 1
and 4-ethynylbenzonitrile 5.
Reaction (2) (Scheme 2) proceeds in homogeneous
conditions and does not require the use of the complex
CuCl–NH4Cl, which was necessary in the heteroge-
neous reaction (1) (Scheme 1). Variation of CuCl
concentration did not affect the yield of compound 7.
Its further oxidative condensation by the corresponding
14-membered heterocycle, 1,8-bis(triflyl)-1,8-diaza-
cyclotetradeca-3,5,10,12-tetrayne was not observed
apparently because the conformation of compound 7
“prepared” to this condensation and shown in Eq. (2)
(Scheme 2) was less sterically favorable than the
conformation with the terminal acetylene group turned
away for each other. The distinction of reaction (2)
occurring in the presence of 20 mol % of CuCl from
reaction (1), requiring a double excess of CuCl [2] is
probably due to the presence of an acidic NH proton in
molecule 1 and its absence in molecule 3. As a result
in the former case the formation of a copper complex
with elimination of the acetylene proton is possible
only in the presence of excess CuCl, after binding of
equimolar amount of CuCl and elimination of more
acidic NH proton.
Cross-coupling product 10 was isolated by column
chromatography; it was a solid substance, well soluble
in chloroform, its structure and composition were pro-
ved by IR and NMR spectra and by elemental analysis
data. In the 13С NMR spectrum of compound 10, like
in that of compound 9, four signals appeared of
nonequivalent acetylene carbon atoms, but three of
Scheme 4.
[O], CuCl
1
HC
CC6H4CN-n
TfNHCH2C
C
C
CC6H4CN-n
+
DMSO, 45oC
_H2O
10
5
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 52 No. 2 2016

SHAINYAN, USHAKOVA
194
them in the region 76.6–77.3 ppm overlapped with the
solvent (chloroform) signal, therefore the structure 10
was unambiguously proved by registering the 13С
NMR spectrum in methanol-d4.
small amount of ether. The combined ether extracts
were dried with MgSO4 and evaporated, the solid residue
was chromatographed on a column packed with silica
gel (70 mesh), eluent dichloromethane–hexane, 1 : 3,
separating the homodimerization products, N,N'-hexa-
2,4-diyne-1,6-diylbis(trifluoromethanesulfonamide) 2
and diphenyldiacetylene 8. Their composition and
spectral characteristics are consistent with the data
previously published in [4] (2) and [5] (8).
In reaction of N-propargyltriflamide 1 with 4-
ethynylnitrobenzene 6 it was impossible to isolate
neither the reaction products nor initial compounds due
to strong resinification in any applied conditions.
EXPERIMENTAL
N-(5-Phenylpenta-2,4-diyn-1-yl)trifluorometha-
nesulfonamide (9). To a solution of 0.54 g (10 mmol)
of NH4Cl and 0.98 g (10 mmol) of CuCl in 10 mL of
water was added dropwise a solution of 1 g (5 mmol)
of N-propargyltriflamide 1 [1] and 0.51 g (5 mmol) of
phenylacetylene in 5 mL of methanol. The reaction
mixture was stirred for 4 h at 40°С, filtered, the filtrate
was extracted with chloroform, the precipitate was washed
with a small amount of chloroform. The combined
extracts were dried with MgSO4 and evaporated, the
residue was chromatographed on a column packed
with silica gel (70 mesh), eluent ethyl acetate–hexane,
1 : 3. Yield 0.42 g (30%), mp 63°С. IR spectrum
(KBr), ν, cm–1: 3322 (NН), 3084, 3065, 2973, 2893,
2251 (С≡С), 2216 (С≡С), 1490, 1377, 1233, 1198,
NMR spectra were registered on a spectrometer
Bruker DPX 400 at operating frequencies 400 (1Н),
100 (13С), 386 (19F) MHz in CDCl3. The chemical
shifts are reported with respect to TMS (1Н, 13С) and
CCl3F (19F).
N,N'-Hexa-2,4-diyne-1,6-diylbis(N-prop-2-yne-1-
trifluoromethanesulfonamide) (7). To a solution of
1 g (4 mmol) of N,N-bispropargyltriflamide 3, syn-
thesized by procedure [4], in 10 mL of DMSO was
added 80 mg (8 mmol) of CuCl. The reaction mixture
was stirred for 8 h at 70°С, poured in water, filtered,
the filtrate was extracted with chloroform, the
precipitate was washed with a small quantity of
chloroform, the combined extracts were washed with
water, dried with MgSO4, evaporated, the residue was
purified by column chromatography on silica gel (70
mesh), eluent hexane–chloroform, 1 : 3. Yield 0.35 g
(20%), yellowish oily liquid. IR spectrum (film), ν,
cm–1: 3301 (≡С–Н), 2985, 2926, 2854, 2131 (С≡С),
1396, 1340, 1230, 1197, 1147, 1078, 955, 905, 781,
607, 521. 1Н NMR spectrum, δ, ppm: 2.48 t (1Н, ≡СН,
J 2.0 Hz), 4.33 d (2Н, НС≡ССН2, J 2.0 Hz), 4.44 s
(2Н, С≡ССН2). 13С NMR spectrum, δ, ppm: 37.62
(С≡ССН2), 37.81 (НС≡ССН2), 70.00 (С≡ССН2),
71.38 (НС≡ССН2), 74.86 (С≡С–С≡С), 75.61 (С≡СН),
119.62 q (СF3, JСF 322.3 Hz). 19F NMR spectrum: δ –
75.55 ppm. Found, %: C 37.12; H 2.42; F 25.53; N
6.65; S 14.24. C14H10F6N2O4S2. Calculated, %: C
37.50; H 2.25; F 25.42; N 6.25; S 14.30.
1
1145, 1056, 990, 849, 757, 690, 609, 526, 514. Н
NMR spectrum, δ, ppm: 4.27 d (2Н, СН2, J 5.6 Hz),
5.40 br.s (1Н, NН), 7.32–7.43 m (3Нm+p), 7.52 d (2Но,
J 7.1 Hz). 13С NMR spectrum, δ, ppm: 34.97 (СН2),
70.74 (NСС), 72.70 (СН2С≡С), 74.89 (PhС≡С), 79.16
(PhС≡С), 119.57 q (СF3, JСF 320.8 Hz), 120.99 (Ci),
128.60 (Cm), 129.81 (Cp), 132.82 (Cо). 19F NMR
spectrum: δ –76.91 ppm Found, %: C 50.43; H 2.70; F
20.48; N 4.54; S 11.32. C12H8F3NO2S. Calculated, %:
C 50.17; H 2.81; F 19.84; N 4.88; S 11.16.
Trifluoro-N-[5-(4-cyanophenyl)penta-2,4-diyn-1-
yl]methanesulfonamide (10). To a solution of 1 g
(5 mmol) of N-propargyltriflamide 1 [1] and 0.63 g
(5 mmol) of 4-ethynylbenzonitrile 5 in 10 mL of DMSO
was added 0.64 g (6.5 mmol) of CuCl. The reaction
mixture was stirred for 8 h at 45°С, poured in water,
filtered, the filtrate was extracted with chloroform, the
precipitate was washed with a small amount of chloro-
form. The combined extracts were washed with water,
dried with MgSO4, and evaporated, the residue was chroma-
tographed on a column packed with silica gel (70 mesh),
eluent hexane–chloroform, 1 : 1. Yield 0.31 g (20%),
mp 98–99°С. IR spectrum (film), ν, cm–1: 3309, 2963,
2925, 2855, 2233, 2172, 2145, 2077, 1603, 1440, 1379,
1232, 1198, 1059, 840, 612, 556. 1Н NMR spectrum, δ,
Reaction of N-propargyltrifluoromethanesulfon-
amide (1) with phenylacetylene (4) in water
solution. To a solution of 0.33 g (25 mmol) of NH4Cl
and 0.98 g (10 mmol) of CuCl in 10 mL of water was
added dropwise 1 g (5 mmol) of N-propargyltriflamide
1 [1] and 0.51 g (5 mmol) of phenylacetylene. The
reaction mixture was stirred for 4 h at room
temperature, filtered, the filtrate was extracted with
ethyl ether, the formed precipitate was washed with, a
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 52 No. 2 2016

HOMO AND HETERO GLASER COUPLING INVOLVING ACETYLENE DERIVATIVES
195
ppm: 4.29 d (2Н, СН2, J 5.8 Hz), 5.36 br.s (1Н, NН),
7.59 d (2Н, Н3,5, J 8.3 Hz), 7.65 d (2Н, Н2,6, J 8.3 Hz).
13С NMR spectrum, δ, ppm: 34.79 (СН2), 69.76
(NСС), 76.64 (СН2С≡С), 76.68 (PhС≡С), 77.30
(PhС≡С), 112.92 (C4), 118.18 (C≡N), 125.96 (C1),
132.25 (C3,5), 133.22 (C2,6). Since in CDCl3 the CF3
quartet was not observed and the signals of the
acetylene carbon atoms were overlapped with the peak
of the solvent, the spectrum of compound was
registered in CD3OD solution. 13С NMR spectrum
(CD3OD), δ, ppm: 34.57 (СН2), 68.76 (NСС), 76.83
(СН2С≡С), 77.33 (PhС≡С), 80.40 (PhС≡С), 114.00
(C4), 119.01 (C≡N), 121.19 q (СF3, JСF 320.1 Hz),
127.31 (C1), 133.46 (C3,5), 134.33 (C2,6). 19F NMR
spectrum: δ –78.56 ppm. Found, %: C 49.61; H 2.46; F
24.98; N 8.92; S 10.04. C13H7F3N2O2S. Calculated, %:
C 50.00; H 2.26; F 25.42; N 8.97; S 10.27.
REFERENCES
1. Shainyan, B.A. and Danilevich, Yu.S., Russ. J. Org.
Chem., 2014, vol. 50, p. 747.
2. Shainyan, B.A. and Ushakova, I.V., Russ. J. Org.
Chem., 2014, vol. 50, p. 1835.
3. Sindhu, K.S. and Anilkumar, G., RSC Adv., 2014, vol. 4,
p. 27867.
4. Shainyan, B.A. and Danilevich, Yu.S., Russ. J. Org.
Chem., 2014, vol. 51, p. 601.
5. Kuznetsova, O.A., Khmara, E.F., Filyakova, V.I.,
Uimin, M.A., Ermakov, A.E., Rhee, C.K., and Charu-
shin, V.N., Russ. J. Gen. Chem., 2007, vol. 77, p. 404.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 52 No. 2 2016