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The Journal of Organic Chemistry
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General procedure for the synthesis of fulvenes containing hydroxyl groups: To a solution of
pyrrolidine (see Table 1 for amounts) and pyrrolidinium perchlorate in acetonitrile (2 mL) were added
cyclopentadiene (1.0 mL, 12 mmol), the appropriate carbonyl derivative (0.65 mL of liquid carbonyls or
0.65 g of solid carbonyls) and molecular sieves (3 Å, 3 g). The reaction was followed by TLC. Upon
completion, the reaction mixture was acidified with diluted HCl (10 ml, 10 %), diluted with water (10 mL)
and extracted with diethyl ether (4 × 20 mL). The organic phases were filtered through a small amount
of silica and the solvent subsequently removed under vacuum.
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6-Phenylfulvene (2a): The product 2a was obtained as an orange solid (643 mg, 65 %). 1H NMR (400
MHz, CDCl3): δ = 7.63–7.58 (m, 2ꢀH), 7.46–7.40 (m, 2ꢀH), 7.40–7.35 (m, 1ꢀH), 7.24 (br s, 1ꢀH), 6.75–
6.71 (m, 1ꢀH), 6.71–6.67 (m, 1ꢀH), 6.56–6.52 (m, 1ꢀH), 6.38–6.34 (m, 1ꢀH) ppm; 13C NMR δ = 145.3 (s),
138.2 (s), 136.4 (s), 130.8 (s), 130.7 (s), 129.0 (s), 128.7 (s), 127.2 (s), 120.4 (s) ppm. The NMR spectral
data are in accordance with those reported in the literature.21
6-(4’-Methoxyphenyl)fulvene (2b): The product 2b was obtained as an orange solid (932 mg, 95 %).
1H NMR (400 MHz, CDCl3): δ = 7.62–7.56 (m, 2ꢀH), 7.17 (br s, 1ꢀH), 6.99–6.92 (m, 2ꢀH), 6.75–6.71 (m,
1ꢀH), 6.69–6.65 (m, 1ꢀH), 6.51–6.47 (m, 1ꢀH), 6.35–6.31 (m, 1ꢀH), 3.87 (s, 3ꢀH) ppm; 13C NMR δ = 160.6
(s), 138.3 (s), 134.9 (s), 132.5 (s), 129.8 (s), 129.6 (s), 127.4 (s), 119.9 (s), 114.3 (s), 55.4 (s) ppm. The
NMR spectral data are in accordance with those reported in the literature.21
6-(4’-Methylthiophenyl)fulvene (2c): The product 2c was obtained as an orange solid (892 mg, 91 %).
1H NMR (400 MHz, CDCl3): δ = 7.57–7.50 (m, 2ꢀH), 7.32–7.24 (m, 2ꢀH), 7.16 (br s, 1ꢀH), 6.73–6.69 (m,
2ꢀH), 6.69–6.65 (m, 1ꢀH), 6.53–6.50 (m, 1ꢀH), 6.35–6.31 (m, 1ꢀH), 2.53 (s, 3ꢀH) ppm; 13C NMR δ = 144.5
(s), 140.7 (s), 137.7 (s), 135.3 (s), 131.1 (s), 130.4 (s), 127.3 (s), 125.9 (s), 119.9 (s), 15.17 (s) ppm.
6-(4’-Hydroxyphenyl)fulvene (1d): The product 2d was obtained as an orange solid (879 mg, 85 %).
1H NMR (400 MHz, CD3CN): δ = 7.58–7.54 (m, 2ꢀH), 7.32 (br s, 1ꢀH), 7.19 (br s, 1ꢀH), 6.91–6.86 (m,
2ꢀH), 6.76–6.72 (m, 1ꢀH), 6.66–6.62 (m, 1ꢀH), 6.45–6.41 (m, 1ꢀH), 6.32–6.29 (m, 1ꢀH) ppm. The NMR
spectral data are in accordance with those reported in the literature.21
6-(4’-Hydroxy-3’-methoxyphenyl)fulvene (1e): The product 2e was obtained as an orange solid
(708 mg, 78 %). 1H NMR (400 MHz, CD3CN): δ = 7.28–7.22 (m, 1ꢀH), 7.22–7.15 (m, 2ꢀH), 6.93–6.84 (m,
1ꢀH), 6.70–6.61 (m, 1ꢀH), 6.48–6.42 (m, 1ꢀH), 6.42–6.27 (m, 1ꢀH), 3.91 (s, 3ꢀH) ppm; 13C NMR δ = 149.3
(s), 148.6 (s), 143.9 (s), 139.9 (s), 135.9 (s), 130.3 (s), 129.9 (s), 128.7 (s), 126.3 (s), 120.6 (s), 116.3
(s), 114.7 (s), 56.8 (s) ppm.
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6-tert-Butylfulvene (2f): The product 2f was obtained as a yellow oil (553 mg, 69 %). H NMR (400
MHz, CDCl3): δ = 6.70–6.67 (m, 1ꢀH), 6.62–6.58 (m, 1ꢀH), 6.45 (br s, 1ꢀH), 6.42–6.39 (m, 1ꢀH), 6.19–
6.15 (m, 1ꢀH), 1.30 (s, 9 H) ppm; 13C NMR δ = 153.7 (s), 134.0 (s), 128.5 (s), 128.4 (s), 119.8 (s), 35.9
(s), 30.9 (s) ppm. UV-Vis (ε): λ = 355 nm (38 M–1 cm–1). The 1H-NMR spectral data are in accordance
with those reported in the literature.20
6-Phenyl-6-methylfulvene (2h): The product 2h was obtained as an orange oil (916 mg, 98 %).
1H NMR (400 MHz, CDCl3): δ = 7.32–7.23 (m, 5ꢀH), 6.56–6.53 (m, 1ꢀH), 6.51–6.45 (m, 1ꢀH), 6.42–6.36
(m, 1ꢀH), 6.13–6.07 (m, 1ꢀH), 2.45 (s, 3ꢀH) ppm; 13C NMR δ = 149.7 (s), 141.9 (s), 131.8 (s), 131.4 (s),
129.1 (s), 129.1 (s), 128.1 (s), 127.8 (s), 123.6 (s), 121.0 (s), 22.55 (s) ppm.
6-(4’-Bromophenyl)-6-methylfulven (2l): The product 2l was obtained as an orange viscous oil
(573 mg, 71 %). 1H NMR (400 MHz, CDCl3): δ = 7.57–7.52 (m, 2ꢀH), 7.31–7.25 (m, 2ꢀH), 6.67–6.63 (m,
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