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TROFIMOV et al.
Methyl 2-butynoate (I). n2D0 1.4325 (lit.: 80–82°C
(85 mm Hg), n1D9 1.4408 [15]).
presence of a copper–palladium catalytic system to
give an important synthon (II), which opens up the real
prospects for the wide use of this product and for the
extension of this new reaction to substituted allenes.
For C5H6O2 anal. calcd. (%): C, 61.20; H, 6.17.
Found (%): C, 60.06; H, 6.38.
IR (microlayer, cm–1): 3000, 2960, 2920, 2840,
2235, 1710, 1430, 1250, 1070, 940, 810, 750, 570.
1H NMR (CDCl3, δ, ppm): 3.74 (s, 3H, OCH3), 1.98 (s,
3H, CH3). 13C NMR (CDCl3, δ, ppm): 152.7 (C=O),
84.12 (CH3–C≡C), 70.91 (CH3–C≡C), 56.32 (CH3),
51.05 (C(O)CH3). MS, m/z (Irel, %): 98 (11), 70 (47), 68
(26), 67 (100), 66 (16), 39 (65), 38 (39), 37 (26), 32
(47), 28 (82).
EXPERIMENTAL
IR spectra were recorded as microlayers and KBr
pellets on Specord IR-75 and Bruker JFS-25 spectro-
photometers. 1H and 13C NMR spectra were measured
on a Bruker DPX-400 instrument (400 MHz) in CDCl3
using HMDS as the internal standard. Mass spectra
were run on a Finnigan GCQ spectrometer with direct
sample injection into the ion source. The products were
separated using a PAKhV-07 preparative chromato-
graph with a katharometer as the detector (75°C,
a 5000 × 10 mm column; Chromaton N-AW-HMDS
as the solid support (0.2–0.25 mm); polyphenyl ether
(15 wt %) as the stationary phase; helium as the car-
rier gas).
Methyl 3-methoxy-3-butenoate (II). n2D3 1.4280.
For C6H10O3 anal. calcd. (%): C, 55.36; H, 7.76.
Found (%): C, 55.03; H, 7.99.
IR (microlayer, cm–1): 3030, 2980, 2950, 2930,
2880, 2810, 1720, 1640, 1440, 1380, 1300, 1270, 1195,
1150, 1100, 1015, 1000, 950, 905, 850, 830, 810, 750,
680, 660. 1H NMR (CDCl3, δ, ppm): 6.29 and 5.84 (dd,
2H, =ëç2), 4.13 (t, 2H, ëç2), 3.77 (s, 3H, OCH3), 3.38
(s, 3H, éëç3). 13C NMR (CDCl3, δ, ppm): 165.93
(C=O), 136.61 (CH2=C), 127.15 (CH2=), 70.04 (CH2),
58.11 (C(O)OCH3), 52.12 (OCH3). MS, m/z (Irel, %):
130 (10), 116 (15), 115 (100), 102 (53), 101 (80), 99
(94), 98 (72), 83 (87), 75 (71), 71 (71), 70 (58), 69 (75),
68 (30), 67 (25), 61 (25), 59 (65), 56 (37), 55 (60), 53
(24), 47 (19), 45 (73), 43 (18), 42 (38), 41 (75), 40 (60),
39 (63), 38 (25), 32 (40), 31 (27), 29 (67), 28 (75), 27
(63), 26 (24).
Methoxycarbonylation of the propyne–allene
mixture. Methanol (200 ml) was placed in a four-neck
flask equipped with a stirrer, a thermometer, a con-
denser connected to a coiled trap (–50°ë), and two bub-
blers (for the introduction of carbon monoxide and the
propyne–allene mixture) and saturated with carbon
monoxide (~1.5 l/h) at room temperature for 30 min.
The temperature was decreased to 0°ë and CO was
bubbled for an additional 1 h. Without termination of
CO bubbling, CuCl2 (9.38 g, 70 mmol), NaOAc (5.74 g,
70 mmol), and PdCl2 (0.106 g, 0.6 mmol) were added.
Then, a 4 : 1 propyne–allene mixture (5.00 g, 125 mmol)
was passed through the reaction mixture at 0–10°ë with
continued feeding of CO. After 1 h, a liquid (~2.00 g)
was collected in the coiled trap; the liquid was recycled
to the reaction mixture as one portion. After stirring for
2 h with continued CO feeding and gradually raising the
temperature to room temperature (the color of the solu-
tion changed from emerald green to brown), the content
of the flask was diluted with cold water (1 : 1) and
extracted with diethyl ether (5 × 200 ml). The ether
extracts were combined, washed with water (4 × 150 ml),
and dried with MgSO4. The extractant was removed
in vacuo to give a crude product containing methyl
2-butynoate (I), methyl 3-methoxy-3-butenoate (II),
and hexa-2,4-diyne (III), which were analyzed and
separated by GLC. The weight of the crude product
(averaged over three experiments) was 1.76 ± 0.04 g.
Composition (%): I (54 ± 2); II (23 ± 2); III (14 ± 3).
The yields of the components (with allowance for the
composition of the propyne–allene mixture) (%): I (9 ± 1);
II (12 ± 1); III (7 ± 1).
Hexa-2,4-diyne. mp 68°ë.
For C6H6 anal. calcd. (%): C, 92.23; H, 7.74.
Found (%): C, 91.98; H, 7.58.
1H NMR (CDCl3, δ, ppm): 1.89 (s).
ACKNOWLEDGMENTS
This work was supported by the Russian Foundation
for Basic Research, project no. 99–03–32939.
REFERENCES
1. Tsuji, M., Takahashi, M., and Takahashi, T., Tetrahedron
Lett., 1980, vol. 21, no. 9, pp. 849–850.
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Abstracts of Papers, VII Vsesoyuznaya konferentsiya po
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Chemistry), Erevan, 1984, p. 109.
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Gritsa, A.I., Zh. Org. Khim., 1985, vol. 21, no. 9, p. 2020.
When the amount of the propyne–allene mixture fed
in the flask was increased to 8.00 g (200 mmol), the
reaction under the same conditions gave 2.40 g of a
crude product with the composition (%): I (45); II (20);
III (12), which corresponds to the following yields of
the components (%): I (7); II (9); III (5).
4. Trofimov, B.A., Gritsa, A.I., Skvortsov, Yu.M., et al.,
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DOKLADY CHEMISTRY Vol. 378 Nos. 1–3 2001