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Synlett 2007(5): 0769-0774  
DOI: 10.1055/s-2007-970780
LETTER
© Georg Thieme Verlag Stuttgart · New York

Magnesium-Promoted One-Pot Double C-Acylation and Cycloaddition of ­Anthracene and Double C-Acylation of Benzyl Acrylates

Masato Matsunami, Nobuyasu Sakai, Tomotaka Morimoto, Hirofumi Maekawa, Ikuzo Nishiguchi*
Department of Chemistry, Nagaoka University of Technology, 1603-1, Kamitomioka-cho, Nagaoka, Niigata 940-2188, Japan
Fax: +81(258)479300; e-Mail: nishiiku@vos.nagaokaut.ac.jp;
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Publication History

Received 20 December 2006
Publication Date:
08 March 2007 (online)

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Abstract

Treatment of anthracene or benzyl acrylate with magnesium turnings for Grignard reaction in the presence of various acid chlorides in N,N-dimethylformamide at room temperature brought about one-pot reductive double C-acylation or tandem intermolecular cycloaddition to give the corresponding C-diacylated products in satisfactory yields.

Key words

magnesium - anthracene - double acylation - cycloaddition - benzyl acrylate

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Typical Procedure for Mg-Promoted One-Pot Double Acylation of Anthracene
In a 50-mL three-necked flask of nitrogen atmosphere were introduced 30 mL of anhyd DMF as solvent, anthracene (5 mmol) as starting material and magnesium metal (10 equiv). Acid chloride (10 equiv) dissolved in 10 mL of DMF was slowly added at 0-5 °C over 20 min. The reaction mixture was stirred at 20-25 °C for 15 h. After reaction, the mixture was poured into sat. NaHCO3 solution. Organic materials were extracted with three 100-mL portions of EtOAc. The organic layer was washed with sat. NaCl solution and dried over anhyd MgSO4. After removal of MgSO4 by filtration and evaporation of the solvent, the isolation by column chromatography gave diacylated compounds in satisfactory yields.

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All the products obtained in this study were characterized by spectroscopic methods (1H NMR, 13C NMR, IR, mass spectra) and elemental analysis, or by comparison of spectroscopic and chromatographic behaviors with those of authentic samples.
9,10-Diacetyl-9,10-dihydroanthracene ( 3a)
Diastereomeric ratio = 68:32. Mp 151-152 °C (major isomer), 137 °C (minor isomer). 1H NMR (400 MHz, CDCl3): δ (major isomer) = 1.71 (s, 6 H), 5.11 (s, 2 H), 7.27-7.35 (m, 8 H) ppm; δ (minor isomer) = 2.19 (s, 6 H), 4.89 (s, 2 H), 7.32-7.41 (m, 8 H) ppm. 13C NMR (100 MHz, CDCl3): δ (major isomer) = 25.50, 58.75, 128.32, 128.68, 130.84, 205.95 ppm; δ (minor isomer) = 28.28, 60.83, 127.47, 129.24, 134.00, 204.74 ppm. IR (KBr): 3070, 3020, 3010, 2960, 2920, 1700, 1490 cm-1. MS (EI): m/z = 264 [M+]. Anal. Calcd for C18H16O2: C, 81.79; H, 6.10. Found: C, 81.93; H, 6.23.
9,10-Dipropionyl-9,10-dihydroanthracene ( 3b).
Diastereomeric ratio = 78:22. Mp 134-135 °C (major isomer), 106-108 °C (minor isomer). 1H NMR (400 MHz, CDCl3): δ (major isomer) = 0.82 (t, J = 7.2 Hz, 6 H), 1.99 (q, J = 7.2 Hz, 4 H), 5.16 (s, 2 H), 7.27-7.35 (m, 8 H) ppm; δ (minor isomer) = 0.95 (t, J = 7.0 Hz, 6 H), 2.54 (q, J = 7.0 Hz, 4 H), 4.88 (s, 2 H), 7.29-7.35 (m, 8 H) ppm. 13C NMR (100 MHz, CDCl3): δ (major isomer) = 8.32, 31.18, 58.36, 128.09, 128.63, 131.23, 209.11 ppm; δ (minor isomer) = 7.78, 33.95, 60.00, 127.23, 129.18, 134.17, 207.25 ppm. IR (KBr): 3030, 2980, 2940, 2890, 1700, 1480 cm-1. MS (EI): m/z = 292 [M+]. Anal. Calcd for C20H20O2: C, 82.16; H, 6.89. Found: C, 82.23; H, 7.03.
9,10-Di( n -butyryl)-9,10-dihydroanthracene ( 3c).
Diastereomeric ratio = 82:18. Mp 113-114 °C (major isomer), 91-93 °C (minor isomer). 1H NMR (400 MHz, CDCl3): δ (major isomer) = 0.60 (t, J = 7.3 Hz, 6 H), 1.35 (sext, J = 7.3 Hz, 4 H), 1.92 (t, J = 7.3 Hz, 4 H), 5.14 (s, 2 H), 7.27-7.36 (m, 8 H) ppm; δ (minor isomer) = 0.82 (t, J = 7.4 Hz, 6 H), 1.50 (sext, J = 7.4 Hz, 4 H), 2.48 (t, J = 7.4 Hz, 4 H), 4.87 (s, 2 H), 7.30-7.39 (m, 8 H) ppm. 13C NMR (100 MHz, CDCl3): δ (major isomer) = 13.47, 17.35, 39.68, 58.53, 128.09, 128.73, 131.01, 208.26 ppm; δ (minor isomer) = 13.65, 17.14, 42.37, 60.30, 127.28, 129.22, 134.03, 206.59 ppm. IR (KBr): 3030, 2960, 2930, 2870, 1710, 1480 cm-1. MS (EI): m/z = 320 [M+]. Anal. Calcd for C22H24O2: C, 82.46; H, 7.55. Found: C, 82.20; H, 7.57.
9,10-Di(isobutyryl)-9,10-dihydroanthracene ( 3d).
Mp 131-133 °C. 1H NMR (400 MHz, CDCl3): δ = 0.69 (d, J = 6.8 Hz, 12 H), 2.39 (sept, J = 6.8 Hz, 2 H), 5.23 (s, 2 H), 7.26-7.36 (m, 8 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 20.70, 37.22, 58.36, 127.88, 129.17, 130.86, 212.44 ppm. IR (KBr): 3060, 3020, 2970, 2930, 2870, 1710, 1490 cm-1. MS (EI): m/z = 320 [M+]. Anal. Calcd for C22H24O2: C, 82.46; H, 7.55. Found: C, 82.39; H, 7.53.
Diethyl 2,3,5,6-Dibenzocyclohexane-1,4-bis(1′,1′′-di-oxa)dibutanoate ( 3e). Mp 110-111 °C. 1H NMR (400 MHz, CDCl3): δ = 1.18 (t, J = 7.2 Hz, 6 H), 2.32-2.39 (m, 8 H), 4.04 (q, J = 7.2 Hz, 4 H), 5.20 (s, 2 H), 7.29-7.37 (m, 8 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 14.14, 28.10, 32.74, 57.74, 60.50, 128.30, 128.70, 130.95, 172.16, 206.59 ppm. IR (KBr): 2980, 2920, 1730, 1710, 1490 cm-1. LCMS (APCI): m/z = 437 [M + H]. Anal. Calcd for C26H28O6: C, 71.54; H, 6.47. Found: C, 71.33; H, 6.44.
9,10-Di(4-chlorobutyryl)-9,10-dihydroanthracene ( 3f). Mp 116 °C. 1H NMR (400 MHz, CDCl3): δ = 1.80 (quin, J = 6.8 Hz, 4 H), 2.13 (t, J = 6.8 Hz, 4 H), 3.28 (t, J = 6.8 Hz, 4 H), 5.18 (s, 2 H), 7.28-7.38 (m, 8 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 26.77, 34.60, 43.91, 58.27, 128.39, 128.70, 130.74, 207.02 ppm. IR (KBr): 3070, 3020, 2960, 2950, 2930, 2900, 1700, 1490 cm-1. LCMS (APCI): m/z = 390 [M + H]. Anal. Calcd for C22H22Cl2O2: C, 67.87; H, 5.70. Found: C, 67.78, H, 5.71.
7,8,9,10-Dibenzobicyclo[4.2.2]deca-2,5-dione ( 5a). Mp 145-147 °C. 1H NMR (400 MHz, CDCl3): δ = 2.22 (s, 4 H), 5.14 (s, 2 H), 7.33-7.45 (m, 8 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 36.64, 62.82, 128.16, 128.54, 132.72, 206.48 ppm. IR (KBr): 3060, 3030, 3020, 2950, 2910, 1690, 1470 cm-1. MS (EI): m/z = 262 [M+]. Anal. Calcd for C18H14O2: C, 82.42; H, 5.38. Found: C, 82.03; H, 5.65.
8,9,10,11-Dibenzobicyclo[5.2.2]4-oxaundeca-2,5-dione ( 5b). Mp 175-176 °C. 1H NMR (400 MHz, CDCl3): δ = 3.93 (s, 4 H), 5.19 (s, 2 H), 7.34-7.43 (m, 8 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 60.48, 79.70, 128.32, 128.42, 131.29, 204.78 ppm. IR (KBr): 3060, 3050, 2950, 2920, 1710, 1480 cm-1. MS (EI): m/z = 278 [M+]. Anal. Calcd for C18H14O3: C, 77.68; H, 5.07. Found: C, 77.95; H, 5.20.
Benzyl 2-(1-Oxopropyl)-4-oxohexanoate ( 7a). 1H NMR (400 MHz, CDCl3): δ = 1.02 (t, J = 7.3 Hz, 3 H), 1.03 (t, J = 7.3 Hz, 3 H), 2.46 (q, J = 7.3 Hz, 2 H), 2.59-2.74 (m, 2 H), 2.93 (dd, J = 5.6, 18.3 Hz, 1 H), 3.15 (dd, J = 8.4, 18.3 Hz, 1 H), 4.07 (dd, J = 5.6, 8.4 Hz, 1 H), 5.12 (d, J = 12.5 Hz, 1 H), 5.16 (d, J = 12.5 Hz, 1 H), 7.30-7.38 (m, 5 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 7.56, 7.63, 35.63, 36.24, 40.38, 52.73, 67.25, 128.04, 128.34, 128.48, 134.98, 168.65, 204.73, 208, 25 ppm. IR (neat): 3034, 2979, 2940, 2882, 1743, 1715, 1655, 1608, 1498, 1457, 1377 cm-1. MS (EI): m/z = 276 [M+]. Anal. Calcd for C28H28N8O10 [di-(2,4-dinitrophenylhydrazone)]: C, 52.83; H, 4.43; N, 17.60. Found: C, 52.78; H, 4.69; N, 17.31.
Benzyl 2-(1-Oxobutyl)-4-oxoheptanoate ( 7b).
1H NMR (400 MHz, CDCl3): δ = 0.84 (t, J = 7.4 Hz, 3 H), 0.89 (t, J = 7.4 Hz, 3 H), 1.57 (sext, J = 7.4 Hz, 4 H), 2.41 (t, J = 7.4 Hz, 2 H), 2.54-2.67 (m, 2 H), 2.91 (dd, J = 5.8, 18.3 Hz, 1 H), 3.12 (dd, J = 8.3, 18.3 Hz, 1 H), 4.06 (dd, J = 5.8, 8.3 Hz, 1 H), 5.12 (d, J = 12.2 Hz, 1 H), 5.16 (d, J = 12.2 Hz, 1 H), 7.30-7.37 (m, 5 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 13.42, 13.61, 16.80, 17.18, 40.65, 44.38, 44.68, 53.03, 67.23, 128.14, 128.34, 128.46, 135.01, 168.63, 203.97, 207.76 ppm. IR (neat): 3036, 2966, 2936, 2877, 1742, 1713, 1648, 1609, 1498, 1456, 1407, 1377cm-1. MS (EI): m/z = 304 [M+]. Anal. Calcd for C18H24O4: C, 71.03; H, 7.95. Found: C, 71.15; H, 8.11.
Benzyl 2-(2-Methyl-1-oxopropyl)-5-methyl-4-oxo-hexanoate ( 7c).
1H NMR (400 MHz, CDCl3): δ = 1.03 (d, J = 6.8 Hz, 3 H), 1.09 (d, J = 7.1 Hz, 3 H), 1.10 (d, J = 7.1 Hz, 3 H), 1.13 (d, J = 7.1 Hz, 3 H), 2.63 (sept, J = 6.8 Hz, 1 H), 2.83-2.98 (m, 2 H), 3.15 (dd, J = 8.2, 18.3 Hz, 1 H), 4.24 (dd, J = 5.6, 8.2 Hz, 1 H), 5.12 (d, J = 12.2 Hz, 1 H), 5.16 (d, J = 12.2 Hz, 1 H), 7.26-7.38 (m, 5 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 17.76, 18.12, 18.17, 18.66, 38.62, 40.68, 40.79, 51.39, 67.29, 128.17, 128.35, 128.48, 135.03, 168.89, 207.90, 211.25 ppm. IR (neat): 3035, 2972, 2935, 2875, 1743, 1713, 1648, 1609, 1498, 1456, 1384 cm-1. MS (EI): m/z = 304 [M+]. Anal. Calcd for C30H32N8O10 [di(2,4-dinitrophenyl-hydrazone)]: C, 54.21; H, 4.85; N,16.86. Found: C, 53.94; H, 5.05; N, 16.68.
Benzyl 2-(3-Methyl-1-oxobutyl)-6-methyl-4-oxo-heptanoate ( 7d).
1H NMR (400 MHz, CDCl3): δ = 0.81 (d, J = 6.6 Hz, 3 H), 0.87 (d, J = 6.6 Hz, 3 H), 0.89 (d, J = 6.6 Hz, 3 H), 0.91 (d, J = 6.6 Hz, 3 H), 2.07-2.17 (m, 2 H), 2.31 (d, J = 7.1 Hz, 2 H), 2.48 (d, J = 6.8 Hz, 2 H), 2.88 (dd, J = 5.8, 18.4 Hz, 1 H), 3.10 (dd, J = 8.3, 18.4 Hz, 1 H), 4.03 (dd, J = 5.8, 8.3 Hz, 1 H), 5.12 (d, J = 12.1 Hz, 1 H), 5.17 (d, J = 12.1 Hz, 1 H), 7.26-7.38 (m, 5 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 22.18, 22.46, 22.50, 22.52, 23.92, 24.72, 41.16, 51.45, 51.61, 53.35, 67.29, 128.29, 128.41, 128.50, 134.99, 168.62, 203.49, 207.56 ppm. IR (neat): 3034, 2959, 2935, 2872, 1743, 1715, 1649, 1610, 1499, 1457, 1368 cm-1. MS (EI): m/z = 332 [M+]. Anal. Calcd for C32H36N8O10 [di(2,4-dinitro-phenylhydrazone)]: C, 55.49; H, 5.24; N,16.18. Found: C, 55.51; H, 5.14; N, 16.18.
Benzyl 4-Oxohexanoate ( 8a).
1H NMR (400 MHz, CDCl3): δ = 1.06 (t, J = 7.3 Hz, 3 H), 2.47 (q, J = 7.3 Hz, 2 H), 2.65 (t, J = 6.2 Hz, 2 H), 2.73 (t, J = 6.2 Hz, 2 H), 5.14 (s, 2 H), 7.34-7.35 (m, 5 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 7.70, 27.97, 35.85, 36.52, 66.42, 128.14, 128.18, 128.50, 135.80, 172.65, 209.33 ppm. IR (neat): 3034, 2977, 2939, 2882, 1735, 1719, 1648, 1608, 1498, 1379 cm-1. MS (EI): m/z = 220 [M+]. Anal. Calcd for C13H16O3: C, 70.89; H, 7.32. Found: C, 70.63; H, 7.09. Benzyl 4-Oxoheptanoate ( 8b).
1H NMR (400 MHz, CDCl3): δ = 0.91 (t, J = 7.4 Hz, 3 H), 1.61 (sext, J = 7.4 Hz, 2 H), 2.42 (t, J = 7.4 Hz, 2 H), 2.64 (t, J = 6.3 Hz, 2 H), 2.72 (t, J = 6.3 Hz, 2 H), 5.14 (s, 2 H), 7.30-7.38 (m, 5 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 13.63, 17.19, 27.90, 36.93, 44.61, 66.39, 128.12, 128.16, 128.48, 135.80, 172.60, 208.86 ppm. IR (neat): 3034, 2962, 2939, 1735, 1715, 1648, 1608, 1498 1456, 1383 cm-1. MS (EI): m/z = 234 [M+]. Anal. Calcd for C14H18O3: C, 71.77; H, 7.74. Found: C, 72.01, H, 8.01.
Benzyl 5-Methyl-4-oxohexanoate ( 8c).
1H NMR (400 MHz, CDCl3): δ = 1.11 (d, J = 6.8 Hz, 6 H), 2.59-2.65 (m, 3 H), 2.78 (t, J = 6.5 Hz, 2 H), 5.11 (s, 2 H), 7.31-7.36 (m, 5 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 18.15, 27.94, 34.65, 40.72, 66.36, 128.13 (× 2), 128.47, 135.82, 172.65, 212.52 ppm. IR (neat): 3034, 2971, 2934, 2876, 1735, 1712, 1608, 1498, 1456, 1384 cm-1. MS (EI): m/z = 234 [M+]. Anal. Calcd for C14H18O3: C, 71.77; H, 7.74. Found: C, 71.84, H, 7.95.
Benzyl 6-Methyl-4oxoheptanoate ( 8d).
1H NMR (400 MHz, CDCl3): δ = 0.91 (d, J = 6.7 Hz, 6 H), 2.10-2.20 (m, 1 H), 2.32 (d, J = 6.7 Hz, 2 H), 2.63 (t, J = 6.2 Hz, 2 H), 2.71 (t, J = 6.2 Hz, 2 H), 5.11 (s, 2 H), 7.33-7.35 (m, 5 H) ppm. 13C NMR (100 MHz, CDCl3): δ = 22.50, 24.62, 27.87, 37.51, 51.69, 66.39, 128.14, 128.17, 128.50, 135.82, 172.61, 208.57 ppm. IR (neat): 3034, 2972, 2957, 2935, 2872, 1735, 1718, 1606, 1497, 1466, 1385 cm-1. MS (EI): m/z = 248 [M+]. Anal. Calcd for C15H20O3: C, 72.55; H, 8.12. Found: C, 72.56; H, 8.29.

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Mg-anthracene·3THF complex can be available from Sigma-Aldrich Co. Ltd.

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Treatment of anthracene(1) with isobutyryl chloride and succinyl dichloride in the presence of 5 equiv of THF (based on 1) in DMF under the similar conditions as mentioned above, gave the corresponding adducts 2d and 5a in 56-59% and 61-63% yields, respectively.

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Typical Procedure for Electroreductive Double C-Acylation of Anthracene Derivatives. Into a 100-mL beaker-type undivided cell equipped with platinum plates [20 × 30 × 0.5 mm, Nacalai Tesque (Kyoto, Japan), 99%] as the cathode and a carbon bar as the anode were introduced 60 mL of anhyd DMF as a solvent, n-Et4NOTs (15 mmol) as a supporting electrolyte, acid dichloride (25 mmol) and anthracene (5 mmol). The electrolysis was carried out under constant current conditions (current density: 7 mA/cm2) at -5 °C to 5 °C with magnetic stirring until 8 F/mol of electricity was passed. After the reaction, the reaction mixture was poured into sat. NaHCO3 solution when acid dichloride was used as the acylating agent. Organic materials were extracted with three 100 mL portions of Et2O. The combined ethereal solution was washed with sat. NaCl solution and dried over anhyd MgSO4. After removal of MgSO4 by filtration and evaporation of the solvent, the isolation by column chromatography gave diacylated compounds in low yields (4%).