OXIDATIVE METHOXYCARBONYLATION OF PROPYNE
1091
the color of the reaction mixture turned from
emerald-green to dark-green. The mixture was left
overnight and became dark-brown.
Methoxycarbonylation of allene. (a) Into a four-
neck flask equipped with a stirrer, thermometer,
reflux condenser connected to a trap cooled to 50 C,
and two bubbler for introduction of carbon monoxide
and allene was charged 200 ml of methanol, and at
0 C it was saturated with carbon monoxide for
The reaction mixture was diluted with cold water
(1: 1), and the reaction products were extracted into
ethyl ether (5 100 ml). The combined ether extracts
were washed with water (4 30 ml) and dried on
MgSO4. The ethyl ether was removed in a vacuum,
and thus 0.60 g of light-yellow liquid was obtained
containing 93.6% of methyl 2-butynoate (I) (GLC)
(0.56 g, yield 19% with respect to propyne charged,
933% with respect to PdCl2) (Table 1, run no. 1).
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30 min at a flow rate 1.5 l h . Under uninterrupted
flow of CO into the flask was placed 9.38g (70mmol)
of CuCl2, 5.74 g (70 mmol) of NaOAc, 0.106 g
(0.6 mmol) of PdCl2. The mixture was cooled to
60 C and at continuous flow of CO through the
reaction mixture was passed 1.00 g (25 mmol) of
allene within 10 min. The condensate collected in the
trap was returned into the reactor. After stirring for
1 h at 40 35 C in continuous flow of CO the
reaction mixture was slowly warmed to room
temperature (the color of solution during the reaction
changed from emerald-green to dark-green). Then the
reaction mixture was diluted with cold water (1: 1)
and extracted with ethyl ether (5 100 ml). The
combined extracts were washed with water (4 30 ml)
and dried with MgSO4. The solvent was removed in
a vacuum. We obtained 0.60 g of liquid that accord-
Run no. 2 was carried out under the similar condi-
tions.
IR spectrum of methyl 2-butynoate (I) (thin film).
1
cm : 3000, 2960, 2920, 2840, 2235, 1710, 1430,
1
1250, 1070, 940, 810, 750, 570. H NMR spectrum
(CDCl3), , ppm: 3.74 s (3H, OCH3), 1.98 s (3H,
CH3). 13C NMR spectrum (CDCl3), , ppm: 152.7
(C=O), 84.12 (CH3 C C), 70.91 (CH3 C C),
56.32 (CH3), 51.05 [C(O)CH3]. IR, 1H and
13C NMR spectra are in agreement with the cor-
responding data for this compound published in [4].
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ing to GLC and H NMR contained methyl 2-(chloro-
methyl)acrylate (III) (73.4%) and methyl 2-(meth-
oxymethyl)acrylate (IV) (19.3%) (Table 2, run no. 1).
(b) Through a reaction mixture obtained under
similar conditions containing 9.38 g (70 mmol) of
CuCl2, 5.74 g (70 mmol) of NaOAc, 0.106 g
(0.6 mmol) of PdCl2 in methanol (200 ml) saturated
with CO was passed a flow of 2.0 g (50 mmol) of
propyne for 45 min. After completion of passing
propyne and without stopping the steam of CO the
mixture was stirred at 10 C for 2 h. The reaction
mixture was warmed to 20 C within 3 h (the color of
solution in the course of the process changes from
emerald-green through dark-green and light-green to
dark brown). Then the reflux condenser was replaced
by Liebig condenser with a receiver and a cooled
trap. By an ordinary distillation at 59 64 C from the
reaction mixture was collected in the receiver 150 ml
of methanol, and in the cooled trap 1 g of propyne
solution in methanol containing according to GLC
4.4% (0.04 g) of unreacted propyne. The IR spectrum
of the liquid condensed in the trap contained an
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IR spectrum of the mixture (thin film), cm : 3030,
2990, 2950, 2930, 2850, 1720, 1640, 1440, 1390,
1330, 1305, 1260, 1195, 1140, 1100, 1050, 990,
950, 915, 830, 810, 750, 680, 650.
1
Methyl 2-(chloromethyl)acrylate (III). H NMR
spectrum (CDCl3), , ppm: 6.36, 5.97 q (2H, =CH2),
4.27 t (2H, CH2), 3.80 s (3H, OCH3). 13C NMR
spectrum (CDCl3), , ppm: 165.25 (C=O), 136.91
(CH2= C ),
128.46
(=CH2),
52.14 [C(O)
OCH3], 42.37 (CH2Cl). Mass spectrum, m/z
(Irel, %): 134 (3), 105 (11), 103 (32), 99 (41), 75 (23),
59 (14), 49 (16), 40 (25), 39 (100), 38 (26), 37
(14).
Methyl 2-(methoxymethyl)acrylate (IV).
1H NMR spectrum (CDCl3) , ppm: 6.29, 5.84 q
(2H, =CH2), 4.13 t (2H, CH2), 3.77 s (3H, OCH3),
3.38 s (3H, OCH3). 13C NMR spectrum (CDCl3), ,
ppm: 165.93 (C=O), 136.61 (CH2= C ), 127.15
(=CH2), 70.40 (CH2), 58.11 (OCH3), 51.42
[C(O)OCH3]. Mass spectrum, 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).
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absorption band at 2120 cm corresponding to the
triple bond of propyne.
The bottoms after distillation were diluted with
water (1: 1), and after workup described under (a)
procedure we obtained 1.45 g of liquid containing
64% of methyl 2-butynoate (GLC) (0.93 g, yield
19% with respect to propyne charged, 1550% with
respect to PdCl2) (Table 1, run no. 3).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 38 No. 8 2002