Palladium-Catalyzed Sonogashira Reaction of Aryl Bromides
3-(4-tert-Butylphenyl)propiolic Acid (3a):[8b] 1-Bromo-4-tert-butyl-
benzene (5.0 mmol, 1.07 g) gave 3a (839.3 mg, 83%). 1H NMR
(300 MHz, [D6]acetone): δ = 7.57 (d, J = 9.0 Hz, 2 H), 7.52 (d, J
= 9.0 Hz, 2 H), 1.33 (s, 9 H) ppm. 13C NMR (75 MHz, [D6]ace-
tone): δ = 155.2, 154.6, 133.5, 126.7, 117.4, 86.3, 81.4, 35.6,
31.3 ppm. HRMS (ESI): calcd. for C13H13O2 [M – H]– 201.0916;
found 201.0914.
13C NMR (75 MHz, [D6]acetone): δ = 154.8, 134.1, 133.8, 133.6,
132.1, 129.4, 128.5, 127.7, 126.0, 125.9, 117.6, 86.5, 84.3 ppm.
HRMS (ESI): calcd. for C13H7O2 [M – H]– 195.0446; found
195.0441.
3-(Naphthalen-2-yl)propiolic Acid (3j): 2-Bromonaphthalene
(5.0 mmol, 1.04 g) gave 3j (794.0 mg, 81%). 1H NMR (300 MHz,
[D6]acetone): δ = 8.26 (s, 1 H), 7.99–7.94 (m, 3 H), 7.63–7.59 (m,
3 H) ppm. 13C NMR (75 MHz, [D6]acetone): δ = 154.6, 134.8 (2
C), 133.7, 129.6, 129.1, 129.0, 129.0, 128.8, 128.1, 117.7, 86.4,
82.0 ppm. HRMS (ESI): calcd. for C12H11O5 [M – H]– 195.0446;
found 195.0447.
3-(4-Ethylphenyl)propiolic Acid (3b): 1-Bromo-4-ethylbenzene
(5.0 mmol, 870.4 mg) gave 3b (749.1 mg, 86%). 1H NMR
(300 MHz, [D6]acetone): δ = 7.55 (d, J = 6.0 Hz, 2 H), 7.33 (d, J
= 9.0 Hz, 2 H), 2.73–2.66 (m, 2 H), 1.25–1.20 (m, 3 H) ppm. 13C
NMR (75 MHz, [D6]acetone): δ = 154.5, 148.6, 133.7, 129.3, 117.6,
86.4, 81.3, 29.4, 15.6 ppm. HRMS (ESI): calcd. for C11H9O2 [M –
H]– 173.0603; found 173.0609.
3-(3,4,5-Trimethoxyphenyl)propiolic Acid (3k):[19] 1-Bromo-3,4,5-
trimethoxybenzene (5.0 mmol, 1.24 g) gave 3k (873.5 mg, 74%). 1H
NMR (300 MHz, [D6]acetone): δ = 6.93 (s, 2 H), 3.88 (s, 6 H), 3.78
(s, 3 H) ppm. 13C NMR (75 MHz, [D6]acetone): δ = 154.7, 154.6,
142.2, 115.1, 111.3, 86.7, 80.9, 60.8, 56.7 ppm. HRMS (ESI): calcd.
for C12H11O5 [M – H]– 235.0607; found 235.0604.
3-Phenylpropiolic Acid (3c):[10] Bromobenzene (5.0 mmol,
1
785.1 mg) gave 3c (679.6 mg, 93%). H NMR (300 MHz, CDCl3):
δ = 7.62 (d, J = 6.0 Hz, 2 H), 7.54–7.44 (m, 1 H), 7.42–7.37 (m, 2
H) ppm. 13C NMR (75 MHz, CDCl3): δ = 158.5, 133.4, 131.3,
128.8, 119.2, 89.2, 80.2 ppm. HRMS (ESI): calcd. for C11H9O2
[M – H]– 145.0290; found 145.031.
3-(Benzo[d][1,3]dioxol-5-yl)propiolic
Acid
(3l):[19]
5-Bro-
mobenzo[d][1,3]dioxole (5.0 mmol, 1.01 g) gave 3l (817.6 mg, 86%).
1H NMR (300 MHz, [D6]acetone): δ = 7.18 (d, J = 3.0 Hz, 1 H),
7.07 (d, J = 3.0 Hz, 1 H), 6.93 (d, J = 9.0 Hz, 1 H), 6.11 (s, 2 H)
ppm. 13C NMR (75 MHz, [D6]acetone): δ = 154.7, 151.2, 149.0,
129.6, 113.4, 112.9, 109.7, 103.1, 86.5, 80.6 ppm. HRMS (ESI):
calcd. for C10H5O4 [M – H]– 189.0188; found 189.0187.
3-o-Tolylpropiolic
Acid
(3d):[10]
1-Bromo-2-methylbenzene
(5.0 mmol, 855.2 mg) gave 3d (656.7 mg, 82%). 1H NMR
(300 MHz, [D6]acetone): δ = 7.50 (d, J = 9.0 Hz, 1 H), 7.43–7.30
(m, 1 H), 7.30–7.12 (m, 2 H), 2.41 (s, 3 H) ppm. 13C NMR
(75 MHz, [D6]acetone): δ = 154.8, 142.6, 133.9, 131.5, 130.6, 126.7,
120.0, 85.5, 85.2, 20.4 ppm. HRMS (ESI): calcd. for C10H7O2 [M –
H]– 159.0446; found 159.0441.
3-[4-(Hydroxymethyl)phenyl]propiolic Acid (3m):[8d] (4-Bro-
mophenyl)methanol (5.0 mmol, 935.2 mg) gave 3m (819.2 mg,
1
93%). H NMR (300 MHz, [D6]acetone): δ = 7.60 (d, J = 9.0 Hz,
2 H), 7.47 (d, J = 9.0 Hz, 2 H), 4.70 (s, 2 H) ppm. 13C NMR
(75 MHz, [D6]acetone): δ = 154.7, 146.9, 133.6, 127.6, 118.7, 86.25,
81.5, 64.1 ppm. HRMS (ESI): calcd. for C10H7O3 [M – H]–
175.0395; found 175.0396.
3-m-Tolylpropiolic
Acid
(3e):[18]
1-Bromo-3-methylbenzene
(5.0 mmol, 855.2 mg) gave 3e (672.7 mg, 84%). 1H NMR
(300 MHz, [D6]acetone): δ = 7.41–7.39 (m, 2 H), 7.34–7.32 (m, 2
H), 2.34 (s, 3 H) ppm. 13C NMR (75 MHz, [D6]acetone): δ = 154.6,
139.6, 134.0, 132.5, 130.7, 129.7, 120.3, 86.31, 81.5, 21.1 ppm.
HRMS (ESI): calcd. for C10H7O2 [M – H]– 159.0446; found
159.0443.
3-(Thiophen-2-yl)propiolic
Acid
(3n):[20]
2-Bromothiophene
(5.0 mmol, 815.2 mg) gave 3n (547.8 mg, 72%). 1H NMR
(500 MHz, [D6]acetone): δ = 7.79 (d, J = 3.0 Hz, 1 H), 7.62 (d, J
= 3.0 Hz, 1 H), 7.25–7.12 (m, 1 H) ppm. 13C NMR (126 MHz,
[D6]acetone): δ = 154.4, 137.7, 132.9, 128.9, 119.8, 85.9, 79.8 ppm.
HRMS (ESI): calcd. for C7H3O2S [M – H]– 150.9854: found
150.9854.
3-p-Tolylpropiolic
Acid
(3f):[10]
1-Bromo-4-methylbenzene
(5.0 mmol, 855.2 mg) gave 3f (608.6 mg, 76%). 1H NMR
(300 MHz, [D6]acetone): δ = 7.52 (d, J = 9.0 Hz, 2 H), 7.29 (d, J
= 6.0 Hz, 2 H), 2.38 (s, 3 H) ppm. 13C NMR (75 MHz, [D6]ace-
tone): δ = 154.6, 142.3, 133.6, 130.4, 117.4, 86.4, 81.4, 21.6 ppm.
HRMS (ESI): calcd. for C10H7O2 [M – H]– 159.0446; found
159.0493.
3-(4-Fluorophenyl)propiolic Acid (3o):[10] 1-Bromo-4-fluorobenzene
(5.0 mmol, 875.0 mg) gave 3o (672.9 mg, 82%). 1H NMR
(300 MHz, [D6]acetone): δ = 7.68 (dd, J = 9.0, 5.4 Hz, 2 H), 7.26–
7.20 (m, 2 H) ppm. 13C NMR (75 MHz, [D6]acetone): δ = 164.8
(d, JC,F = 255.0 Hz), 154.8, 136.3 (d, JC,F = 7.5 Hz), 117.2 (d, JC,F
= 22.5 Hz), 116.9, 84.9, 81.8 ppm. HRMS (ESI): calcd. for
C9H4FO2 [M – H]– 163.0195; found 163.0193.
3-(2-Methoxyphenyl)propiolic Acid (3g):[10] 1-Bromo-2-methoxy-
benzene (5.0 mmol, 935.2 mg) gave 3g (678.2 mg, 77%). H NMR
(300 MHz, [D6]acetone): δ = 7.51 (d, J = 6.0 Hz, 1 H), 7.49–7.40
(m, 1 H), 7.06 (d, J = 9.0 Hz, 1 H), 6.98 (t, J = 7.1 Hz, 1 H), 3.87
(s, 3 H) ppm. 13C NMR (75 MHz, [D6]acetone): δ = 162.4, 154.8,
135.3, 133.4, 121.4, 112.1, 109.3, 85.5, 83.5, 56.2 ppm. HRMS
(ESI): calcd. for C10H7O3 [M – H]– 175.0395; found 175.0393.
1
3-(4-Chlorophenyl)propiolic Acid (3p):[10] 1-Bromo-4-chlorobenzene
(5.0 mmol, 957.3 mg) gave 3p (711.0 mg, 79%). 1H NMR
(300 MHz, [D6]acetone): δ = 7.66 (d, J = 9.0 Hz, 2 H), 7.52 (d, J
= 9.0 Hz, 2 H) ppm. 13C NMR (75 MHz, [D6]acetone): δ = 154.1,
137.0, 134.9, 129.8, 119.0, 84.1, 82.4 ppm. HRMS (ESI): calcd. for
C9H4ClO2 [M – H]– 178.9900; found 178.9902.
3-(4-Methoxyphenyl)propiolic Acid (3h):[10] 1-Bromo-4-methoxy-
benzene (5.0 mmol, 935.2 mg) gave 3h (687.1 mg, 78%). H NMR
(300 MHz, [D6]acetone): δ = 7.56 (d, J = 9.0 Hz, 2 H), 7.00 (d, J
= 9.0 Hz, 2 H), 3.84 (s, 3 H) ppm. 13C NMR (75 MHz, [D6]ace-
tone): δ = 161.8, 154.1, 134.7, 114.6, 111.2, 86.0, 80.3, 55.0 ppm.
HRMS (ESI): calcd. for C10H7O3 [M – H]– 175.0395; found
175.0389.
1
3-(4-Cyanophenyl)propiolic Acid (3q):[8d] 4-Bromobenzonitrile
(5.0 mmol, 910.1 mg) gave 3q (727.4 mg, 85%). 1H NMR
(500 MHz, [D6]acetone): δ = 7.91 (d, J = 6.0 Hz, 2 H), 7.85 (d, J
= 6.0 Hz, 2 H) ppm. 13C NMR (126 MHz, [D6]acetone): δ = 154.1,
134.3, 133.5, 125.2, 118.6, 114.9, 84.4, 83.5 ppm. HRMS (ESI):
calcd. for C10H4NO2 [M – H]– 170.0242; found 170.0249.
3-(Naphthalen-1-yl)propiolic Acid (3i):[10] 1-Bromonaphthalene
(5.0 mmol, 1.04 g) gave 3i (852.8 mg, 87%). 1H NMR (300 MHz,
[D6]acetone): δ = 8.29 (d, J = 9.0 Hz, 1 H), 7.98 (d, J = 9.0 Hz, 1
H), 7.90 (d, J = 9.0 Hz, 1 H), 7.85 (d, J = 6.0 Hz, 1 H), 7.62 (t, J
= 6.0 Hz, 1 H), 7.54 (t, J = 6.0 Hz, 1 H), 7.51–7.41 (m, 1 H) ppm.
3-[4-(Methoxycarbonyl)phenyl]propiolic Acid (3r):[10] Methyl 4-
bromobenzoate (5.0 mmol, 1.8 g) gave 3r (888.2 mg, 87%). 1H
NMR (300 MHz, [D6]DMSO): δ = 8.00 (d, J = 9.0 Hz, 2 H), 7.76
Eur. J. Org. Chem. 2013, 1973–1978
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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1977