LETTER
Regioselective Mg-Promoted C-Acylation
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(3) For electrochemical acylation, see : (a) Lund, H.; Degrand,
C. Acta Chem. Scand. 1979, B33, 57. (b) Degrand, C.;
Mora, R.; Lund, H. Acta Chem. Scand. 1979, B37, 429.
(c) Lund, H.; Degrand, C. Tetrahedron Lett. 1977, 3593.
(4) For electrochemical carbonation, see: (a) Wawzonek, S.;
Blaha, E. W.; Berkey, R.; Runner, M. E. J. Electrochem.
Soc. 1955, 102, 235. (b) Derien, S.; Dunach, E.; Perichon, J.
J. Am. Chem. Soc. 1991, 113, 8447.
(5) (a) Shono, T.; Nishiguchi, I.; Ohmizu, H. J. Am. Chem. Soc.
1977, 99, 7396. (b) Ohno, T.; Aramaki, H.; Nakahiro, H.;
Nishiguchi, I. Tetrahedron 1996, 52, 1943.
(6) (a) Ohno, T.; Sakai, M.; Ishino, Y.; Shibata, T.; Maekawa,
H.; Nishiguchi, I. Org. Lett. 2001, 3, 3439. (b) Kyoda, M.;
Yokoyama, T.; Maekawa, H.; Ohno, T.; Nishiguchi, I.
Synlett 2001, 1535.
EI–MS: m/z 266 (M+). Anal. Calcd for C19H22O: C, 85.67; H,
8.32. Found: C, 85.66; H, 8.32. Mp: 66–68 °C.
1-Propionylacenaphthene(6b): 1H NMR (400 MHz,
CDCl3) 1.04 (t, J = 7.2 Hz, 3 H), 2.48 (dq, J = 7.2 Hz, J =
16.0 Hz, 1 H), 2.64 (dq, J = 7.2 Hz, J = 16.0 Hz, 1 H), 3.53
(dd, J = 8.4 Hz, J = 17.4 Hz, 1 H), 3.70 (dd, J = 3.4 Hz, J =
17.4 Hz, 1 H), 4.57 (dd, J = 3.4 Hz, J = 8.4 Hz, 1 H), 7.29 (d,
J = 7.5 Hz, 1 H), 7.33 (d, J = 7.5 Hz, 1 H), 7.44 (t, J = 7.5
Hz, 1 H), 7.45 (t, J = 7.5 Hz, 1 H), 7.60 (d, J = 7.5 Hz, 1 H)
and 7.64 (d, J = 7.5 Hz, 1 H) ppm. 13C NMR (CDCl3) 7.85,
33.37, 33.86, 56.34, 119.61, 119.85, 122.63, 123.80, 127.64,
128.10, 131.68, 138.56, 142.49, 143.37 and 209.31 ppm.
IR(neat): 3040, 2940, 1710, 1600, 1490, 1450, 1370 and
1110 cm–1. EI–MS: m/z 210 (M+).
1-(n-Butyryl)acenaphthene(6c): 1H NMR (400 MHz,
CDCl3) 0.86 (t, J = 7.4 Hz, 3 H), 1.61 (sext, J = 7.4 Hz, 2
H), 2.45 (dt, J = 7.4 Hz, J = 17.2 Hz, 1 H), 2.58 (dt, J = 7.4
Hz, J = 17.2 Hz, 1 H), 3.54 (dd, J = 8.5 Hz, J = 17.5 Hz, 1
H), 3.70 (dd, J = 3.6 Hz, J = 17.5 Hz, 1 H), 4.57 (dd, J = 3.6
Hz, J = 8.5 Hz, 1 H), 7.31 (d, J = 7.5 Hz, 1 H), 7.34 (d, J =
7.5 Hz, 1 H), 7.45 (t, J = 7.5 Hz, 1 H), 7.46 (t, J = 7.5 Hz, 1
H), 7.61 (d, J = 7.5 Hz, 1 H) and 7.66 (d, J = 7.5 Hz, 1 H)
ppm. 13C NMR (CDCl3) 13.67, 17.09, 33.80, 42.03, 56.61,
119.67, 119.92, 122.68, 123.84, 127.68, 128.13, 131.75,
138.65, 142.45, 143.40 and 208.71 ppm. IR(neat): 3040,
2960, 1710, 1600, 1500, 1450, 1370 and 1120 cm–1. EI–MS:
m/z 224 (M+).
(7) Commercially available Mg turnings for Grignard reaction
was used without any pre-treatment.
(8) Typical procedure is as follows: Into a N,N-
dimethylformamide (DMF, 20 mL) solution containing
commercially available Mg turnings (40 mmol) for Grignard
reaction and H2O (5.6 mmol) was added dropwise a DMF
solution (40 mL) of stilbene (1a, 10 mmol), trimethylsilyl
chloride (TMSCl, 20 mmol), and acid anhydride(2a–d: 100
mmol) at 15–20 °C with magnetic stirring under nitrogen
atmosphere during a period of 45 min. After the addition, the
mixture was stirred at room temperature overnight.
Treatment of the reaction mixture according to usual work-
up gave 2-acyl-1,2-diphenylethanes (3a–d) in 73–59%
yields accompanying a small amount (4–9%yield) of
dibenzyl as a by-product. The products, 3,4-diphenyl-2-
butanone(3a),3a 1,2-diphenyl-3-pentanone(3b),9 4-
methyl-1,2-diphenyl-3-pentanone(3d),10 3-methyl-3,4-
diphenyl -2-butanone(4a),11 2-methyl-1,2-diphenyl-3-
pentanone(4b),12 and 1-acetylacenaphthene(6a)3a were
identified by comparison of their gas chromatography and
spectroscopic behaviors with those of their authentic
samples. The other products were characterized by
spectroscopic methods (1H- and 13C NMR, IR, MASS) and
elemental analysis.
1-Acetyl-1-methylacenaphthene(7a): 1H NMR (400 MHz,
CDCl3) 1.60 (s, 3 H), 1.92 (s, 3 H), 3.23 (d, J = 18.0 Hz, 1
H), 3.82 (d, J = 18.0 Hz, 1 H), 7.22 (d, J = 7.8 Hz, 1 H), 7.34
(d, J = 7.8 Hz, 1 H), 7.48 (t, J = 7.8 Hz, 1 H), 7.51 (t, J = 7.8
Hz, 1 H), 7.67 (d, J = 7.8 Hz, 1 H) and 7.69(d, J = 7.8Hz, 1
H) ppm. 13C NMR (CDCl3) 24.04, 25.31, 43.46, 60.34,
118.95, 119.89, 122.94, 123.96, 128.02, 128.26, 131.74,
138.25, 142.27, 148.07 and 208.58 ppm. IR(neat): 3050,
2960, 1700, 1600, 1490, 1420 and 1350 cm–1. EI–MS: m/z
210 (M+).
1-Methyl-1-propionylacenaphthene(7b): 1H NMR (400
MHz, CDCl3) 0.92 (t, J = 7.2 Hz, 3 H), 1.61 (s, 3 H), 2.14
(dq, J = 7.2 Hz, J = 17.6 Hz, 1 H), 2.29 (dq, J = 7.2 Hz, J =
17.6 Hz, 1 H), 3.23 (d, J = 17.6 Hz, 1 H), 3.79 (d, J = 17.6
Hz, 1 H), 7.20 (d, J = 7.5 Hz, 1 H), 7.33 (d, J = 7.5 Hz, 1 H),
7.47 (t, J = 7.5 Hz, 1 H), 7.50 (t, J = 7.5 Hz, 1 H), 7.66 (d, J
= 7.5 Hz, 1 H) and 7.68 (d, J = 7.5 Hz, 1 H) ppm. 13C NMR
(CDCl3) 8.42, 24.28, 30.70, 43.66, 60.01, 118.95, 119.81,
122.90, 123.84, 128.00, 128.22, 131.70, 138.36, 142.42,
148.34 and 211.52 ppm. IR(neat): 3050, 2970, 1710, 1600,
1500, 1450 and 1370 cm–1. EI–MS: m/z 224 (M+).
1-(n-Butyryl)-1-methylacenaphthene(7c):1H NMR (400
MHz, CDCl3) 0.71 (t, J = 7.4 Hz, 3 H), 1.43–1.53 (m, 2 H),
1.60 (s, 1 H), 2.10 (dt, J = 7.3 Hz, J = 17.0 Hz, 1 H), 2.24 (dt,
J = 7.3 Hz, J = 17.0 Hz, 1 H), 3.21 (d, J = 17.8 Hz, 1 H), 3.80
(d, J = 17.8 Hz, 1 H), 7.20 (d, J = 7.4 Hz, 1 H), 7.34 (d, J =
7.4 Hz, 1 H), 7.47 (t, J = 7.4 Hz, 1 H), 7.51 (t, J = 7.4 Hz, 1
H), 7.66 (d, J = 7.4 Hz, 1 H) and 7.68 (d, J = 7.4 Hz, 1 H)
ppm. 13C NMR(CDCl3) 13.54, 17.40, 24.26, 39.29, 43.44,
60.10, 119.03, 119.81, 122.90, 123.84, 127.99, 128.21,
131.70, 138.39, 142.45, 148.23 and 210.65 ppm. IR(neat):
3050, 2950, 1710, 1600, 1490, 1460 and 1370cm–1.EI–MS:
m/z 238 (M+).
1,2-Diphenyl-3-hexanone(3c): 1H NMR (400 MHz,
CDCl3) 0.71 (t, J = 7.6 Hz, 3 H), 1.39–1.50 (m, 2 H), 2.17–
2.35 (m, 2 H), 2.90 (dd, J = 7.3 Hz, J = 13.7 Hz, 1 H), 3.42
(dd, J = 7.3 Hz, 13.7 Hz, 1 H), 3.91 (t, J = 7.3 Hz, 1 H) and
7.03–7.35 (m, 10 H) ppm. 13C NMR (CDCl3) 13.43, 17.01,
38.69, 44.28, 60.82, 126.05, 127.24, 128.21, 128.33, 128.79,
128.99, 138.59, 139.82 and 209.77 ppm.. IR(neat): 3010,
2960, 1720, 1600, 1490, 1450, 1380 and 1110 cm–1. EI–MS:
m/z 252 (M+). Anal. Calcd for C18H20O: C, 85.67; H, 7.99.
Found: C, 85.25; H, 8.01.
2-Methyl-1,2-diphenyl-3-hexanone(4c): 1H NMR (400M
Hz, CDCl3) 0.77 (t, J = 7.3 Hz, 3 H), 1.41 (s, 3 H), 1.48–
1.58 (m, 2 H), 2.14–2.25 (m, 2 H), 3.17 (d, J = 13.7 Hz, 1 H),
3.22 (d, J = 13.7 Hz, 1 H) and 6.65–7.33 (m, 10 H) ppm. 13
NMR (CDCl3) 13.63, 17.73, 19.89, 40.06, 44.39, 56.35,
125.97, 126.94, 127.02, 127.46, 128.44, 130.53, 137.84,
C
141.76 and 212.49 ppm.. IR(neat): 3020, 2950, 1710, 1590,
1490, 1450, 1380 and 1120 cm–1. EI–MS: m/z 266 (M+).
Anal. Calcd for C19H22O: C, 85.67; H, 8.32. Found: C, 85.43;
H, 8.45.
2,4-Dimethyl-1,2-diphenyl-3-pentanone(4d): 1H NMR
(400 MHz, CDCl3) 0.85 (d, J = 6.8 Hz, 3 H), 1.02 (d, J =
6.8 Hz, 3 H), 1.45 (s, 3 H), 2.65 (sept, J = 6.8 Hz, 1 H), 3.16
(d, J = 13.7 Hz, 1 H), 3.22 (d, J = 13.7 Hz, 1 H) and 6.61–
7.36 (m, 10 H) ppm. 13C NMR (CDCl3) 19.23, 21.02,
21.17, 36.26, 44.27, 56.94, 125.92, 127.09, 127.46, 127.49,
128.37, 130.53, 137.94, 140.71 and 216.99 ppm. IR(neat):
3020, 2960, 1720, 1600, 1490, 1450, 1380 and 1110 cm–1.
(9) Prashad, M.; Seth, M.; Bhaduri, A. P. J. Indian Chem. Soc.
1980, 1115.
(10) Sawaki, Y.; Ogata, Y. J. Am. Chem. Soc. 1977, 99, 5412.
(11) Aranda, A.; Diaz, A.; Diez-Barra, E.; Antonio, H.; Moreno,
A.; Sanchez-Verdu, P. J. Chem. Soc., Perkin Trans. 1 1992,
2427.
(12) Maria, C. F.-M.; Ruiz, M. P. J. Chem. Research 1990, 46.
Synlett 2002, No. 5, 759–762 ISSN 0936-5214 © Thieme Stuttgart · New York