K. Okuma et al.
Bull. Chem. Soc. Jpn. Vol. 84, No. 3 (2011)
331
being stirred for 13 h at rt, sat. aq. NaCl solution (10 mL) was
added to this suspension, and extracted with dichloromethane
(7 mL © 3). The combined extract was dried over sodium
sulfate, filtered, and evaporated to give brown oily solid,
which was chromatographed over silica gel by elution with
hexane:ethyl acetate (10:1) to give 5 (0.014 g, 0.08 mmol) and
6 (0.023 g, 0.12 mmol) then eluted with ethyl acetate to afford
(mp 127-128 °C). 1H NMR (CDCl3): ¤ 2.00 (d, J = 8.4 Hz,
OH), 5.85 (d, 1H, J = 8.4 Hz, CH), 7.08-7.24 (m, 4H, Ar),
7.36 (dd, 2H, J = 6.8 and 7.6 Hz, Ar), 7.61 (d, 2H, J =
7.6 Hz, Ar). MS: Calcd for C13H10O2: 198.02. Found: 198.06
(M+).
Reaction of N,N-Dimethylthioformamide (10) with Tri-
flate 1a. To a suspension of CsF (0.339 g, 2.2 mmol) and
triflate 1a (0.360 g, 1.2 mmol) in acetonitrile (15 mL) was
added 10 (0.045 g, 0.50 mmol). After being stirred for 13 h at
rt, sat. aq. NaCl solution (10 mL) was added to this suspen-
sion, and extracted with dichloromethane (7 mL © 3). The
combined extract was dried over sodium sulfate, filtered,
and evaporated to give brown oil. A small amount of DMF
was detected by 1H NMR in the reaction mixture. This mixture
was chromatographed over silica gel by elution with
hexane:ethyl acetate (10:1) to give diphenyl sulfide (0.056 g,
0.30 mmol), 1H NMR data of which was identical with the
authentic sample. Further elution gave 5 (0.009 g, 0.05 mmol),
6 (0.012 g, 0.06 mmol), and ammonium triflate 7a (0.105 g,
0.30 mmol).
Reaction of N,N-Dimethylacetamide (11) with Triflate 1a.
To a solution of CsF (0.352 g, 2.3 mmol) and triflate 1a
(0.360 g, 1.2 mmol) in acetonitrile (10 mL) was added 11
(0.044 g, 0.50 mmol). After being stirred for 15 h at rt, sat. aq.
NaCl solution (10 mL) was added to this suspension, and
extracted with dichloromethane (7 mL © 3). The combined
extract was dried over sodium sulfate, filtered, and evaporated
to give pale brown oil. 1H NMR of the mixture showed mainly
the peaks of 11 and biphenylene. Careful separation of silica
gel chromatography by elution with hexane:ethyl acetate (10:1)
resulted in the isolation of 11 (0.026 g, 0.30 mmol) and
biphenylene (0.015 g, 0.10 mmol).
Reaction of N-Acetylimidazole (12) with Triflate 1a. To a
suspension of CsF (0.26 g, 1.7 mmol) and triflate 1a (0.274 g,
0.92 mmol) in acetonitrile (10 mL) was added 12 (0.023 g,
0.21 mmol). After being stirred for 16 h at rt, sat. aq. NaCl
solution (10 mL) was added to this suspension, and extracted
with dichloromethane (7 mL © 3). The combined extract was
dried over sodium sulfate, filtered, and evaporated to pale give
brown oil, which was subjected to PTLC to afford 13 (0.062 g,
0.18 mmol). Greenish yellow crystals; mp 232-234 °C (lit.21
mp 233-234 °C). 1H NMR (CDCl3): ¤ 6.87 (t, J = 7.2 Hz, 1H),
7.53 (t, J = 3.2 Hz, 2H), 7.69 (t, J = 3.6 Hz, 2H), 8.05 (d,
J = 8.4 Hz, 2H), 8.10 (d, J = 8.0 Hz, 2H), 8.50 (s, 1H).
13C NMR (CDCl3): ¤ 120.40, 121.41, 124.53, 125.76, 126.92,
127.15, 129.16, 129.45, 130.91, 133.03, 137.41, 147.94. IR
(¯): 3053, 2921, 1723, 1589, 1489, 1325, 1288, 1180, 1030,
892, 734, 687 cm¹1. HRMS Calcd for C26H19N: [M]+
345.1517; Found, 345.1510.
1
7a (0.107 g, 0.31 mmol). Compound 5: H NMR (CDCl3): ¤
4.05 (s, 2H, CH2), 6.95-7.07 (m, 4H, Ar), 7.14-7.22 (m, 4H,
Ar). Compound 6: 1H NMR (CDCl3): ¤ 7.38 (t, 2H, J = 8.0 Hz,
Ar), 7.50 (d, 2H, J = 8.0 Hz, Ar), 7.72 (t, 2H, J = 8.0 Hz, Ar),
8.35 (d, 2H, J = 8.0 Hz, Ar).
1
Compound 7a: Pale yellow oil: H NMR (CDCl3): ¤ 4.04
(s, 6H, CH3), 7.59 (br s, 8H, Ph). 13C NMR (CDCl3): ¤ 58.81
(CH3), 120.95 (q, J = 320 Hz, CF3), 121.40, 130.87, 130.97,
148.79 (Ar). Elemental analysis was carried out as its
tetraphenylborate: Anal. Found: C, 85.12; H, 7.18; N, 2.63%.
Calcd for C38H38BNO: C, 85.23; H, 7.15; N, 2.62%.
Reaction of Formylmorpholine with Triflate 1a. To a
suspension of CsF (0.339 g, 2.2 mmol) and triflate 1a (0.360 g,
1.2 mmol) in acetonitrile (8 mL) was added formylmorpholine
(0.058 g, 0.50 mmol). After being stirred for 14 h at rt, sat.
aq. NaCl solution (10 mL) was added to this suspension, and
extracted with dichloromethane (7 mL © 3). The combined
extract was dried over sodium sulfate, filtered, and evaporated
to give brown oily solid, which was chromatographed over
silica gel by elution with hexane:ethyl acetate (10:1) to give
5 (0.013 g, 0.08 mmol) and 6 (0.022 g, 0.12 mmol) then eluted
with ethyl acetate to afford 7b (0.121 g, 0.31 mmol). Com-
1
pound 7b: H NMR (CDCl3): ¤ 4.10 (m, 4H, CH2), 4.77 (m,
4H, CH2), 7.44 (t, 2H, J = 7.6 Hz, Ar), 7.56 (t, 4H, J = 7.6 Hz,
Ar), 7.81 (d, 4H, J = 7.6 Hz, Ar). 13C NMR (CDCl3): ¤ 62.48
(CH2), 63.74 (CH2), 120.85 (q, J = 330 Hz, CF3), 121.77,
130.74, 131.58, 146.33. Elemental analysis was carried out
as its tetraphenylborate. Anal. Found: C, 83.51; H, 6.58; N,
2.33%. Calcd for C40H38BNO (+H2O): C, 83.18; H, 6.98; N,
2.43%.
Reaction of N,N-Dimethylaniline with Triflate 1a. To a
suspension of CsF (0.339 g, 2.2 mmol) and triflate 1a (0.360 g,
1.2 mmol) in acetonitrile (8 mL) was added N,N-dimethylani-
line (0.061 g, 0.50 mmol). After being stirred for 13 h at rt, sat.
aq. NaCl solution (10 mL) was added to this suspension, and
extracted with dichloromethane (7 mL © 3). The combined
extract was dried over sodium sulfate, filtered, and evaporated
to give brown oil, which was chromatographed over silica gel
by elution with ethyl acetate to give ammonium triflate 7a
(0.149 g, 0.43 mmol).
Reaction of DMF with Triflate 1a in the Presence of
K2CO3. To a suspension of CsF (0.339 g, 2.2 mmol), triflate
1a (0.360 g, 1.2 mmol), and K2CO3 (0.42 g, 3.0 mmol) in
acetonitrile (6 mL) was added DMF (0.037 g, 0.50 mmol).
After being stirred for 14 h at rt, sat. aq. NaCl solution
(10 mL) was added to this suspension, and extracted with
dichloromethane (7 mL © 3). The combined extract was dried
over sodium sulfate, filtered, and evaporated to give brown
oily solid, which was chromatographed over alumina by
elution with hexane:ethyl acetate (10:1) to give 8 (0.051 g,
0.26 mmol). Colorless crystals: mp 127-128 °C. 1H NMR
spectral data and mp were identical with the authentic sample
Reaction of N-Acetylimidazole (12) with Triflate 1a in
CD3CN. To a suspension of CsF (0.015 g, 0.10 mmol) and
triflate (0.010 g, 0.033 mmol) in CD3CN (0.4 mL) was added
imidazole 12 (0.011 g, 0.10 mmol) in CD3CN (0.2 mL). The
1
reaction was monitored by H NMR. After standing for 15 h,
acetic acid (28%) and 14 (20%) was formed. Imidazole 12
1
(60%) remained unreacted. Acetic acid: H NMR (CD3CN): ¤
1.91 (s, 3H). Compound 14: 1H NMR (CD3CN): ¤ 7.11 (s, 1H,
imidazole), 7.35-7.42 (m, 1H, Ph), 7.42-7.54 (m, 4H, Ph), 7.45
(s, 1H, imidazole), 7.92 (s, 1H, imidazole).