TMSOTf-Promoted Addition of Alkynes to Aldehydes
0.57 mmol) in freshly distilled diethyl ether (10 mL) under nitrogen
at –78 °C. After the reaction mixture had been stirred at –78 °C for
3 h, it was warmed slowly to room temperature and stirred for 22 h
until the reaction was complete (monitored by TLC). The solution
was quenched with water (20 mL) and extracted with EtOAc
(3ϫ10 mL). The organic layer was washed with brine, dried with
MgSO4, filtered and evaporated under reduced pressure. The resi-
due was purified by column chromatography on silica gel (hexane/
EtOAc = 20:1) to produce the unsaturated ketone 2a (135 mg,
Ͼ99%) as a colourless oil. 1H NMR (CDCl3, 400 MHz): δ = 12.00
(s, 1 H), 7.80 (dd, J = 8.0, 1.6 Hz, 1 H), 7.50–7.35 (m, 6 H), 7.06–
6.89 (m, 2 H), 6.86 (s, 1 H), 2.75 (t, J = 7.8 Hz, 2 H), 1.54–1.36
(m, 4 H), 0.89 (t, J = 4.9 Hz, 3 H) ppm. 13C NMR (CDCl3,
100 MHz): δ = 204.4, 163.2, 141.0, 137.1, 136.2, 135.4, 132.9, 129.1,
128.6, 128.3, 119.5, 118.6, 118.4, 30.8, 28.5, 22.9, 13.9 ppm. HRMS
(EI): calcd. for C19H20O2 [M]+ 280.1463; found 280.1463.
204.1, 163.2, 141.6, 136.3, 135.4, 134.2, 133.8, 132.7, 130.3, 128.8,
119.3, 118.6, 118.4, 30.6, 28.5, 22.9, 13.8 ppm. HRMS (EI): calcd.
for C19H19O2Cl [M]+ 314.1073; found 314.1074.
(E)-1-(2-Hydroxyphenyl)-2-(4-nitrobenzylidene)hexan-1-one
(2a):
Entry 6 in Table 2. Purification by column chromatography (silica
gel, EtOAc/Hex = 1:20) provided compound 2a (95 mg, 61%) as a
light-yellow solid along with 4a (34 mg, 37%).
1
2a: H NMR (CDCl3, 400 MHz): δ = 11.90 (s, 1 H), 8.25 (dd, J =
7.0, 1.7 Hz, 2 H), 7.78 (dd, J = 8.0, 1.6 Hz, 1 H), 7.53–7.50 (m, 3
H), 7.05–6.90 (m, 2 H), 6.82 (s, 1 H), 2.72–2.63 (m, 2 H), 1.52–1.33
(m, 4 H), 0.87 (t, J = 7.2 Hz, 3 H) ppm. 13C NMR (CDCl3,
100 MHz): δ = 203.5, 163.3, 147.1, 144.2, 142.0, 136.7, 133.1, 132.6,
129.7, 123.8, 118.9, 118.8, 118.6, 30.5, 28.9, 22.8, 13.7 ppm. HRMS
(EI): calcd. for C19H19O4N [M]+ 325.1314; found 325.1314.
(E)-1-(2-Hydroxyphenyl)-2-(4-methylbenzylidene)hexan-1-one (2a)
and 3-Butyl-2-(p-tolyl)chroman-4-one (3a): Entry 7 in Table 2. Puri-
fication by column chromatography (silica gel, EtOAc/Hex = 1:20)
provided compound 2a (209 mg, 81%) as a light-yellow oil and 3a
(17 mg, 8%) also as a yellow oil.
(E)-1-(2-Hydroxyphenyl)-2-propylidenehexan-1-one (2a): Entry 1 in
Table 2. Purification by column chromatography (silica gel, EtOAc/
Hex = 1:20) provided compound 2a (68 mg, 69%) as a light-yellow
oil. 1H NMR (CDCl3, 400 MHz): δ = 12.03 (s, 1 H), 7.67–7.65 (m,
1 H), 7.44–7.40 (m, 1 H), 6.98–6.84 (m, 1 H), 6.88–6.84 (m, 1 H),
5.94 (m, 1 H), 2.47–2.45 (m, 2 H), 2.31–2.27 (m, 2 H), 1.38–1.34
(m, 4 H), 1.04 (t, J = 7.3 Hz, 3 H), 0.89 (t, J = 6.9 Hz, 3 H) ppm.
13C NMR (CDCl3, 100 MHz): δ = 204.1, 162.9, 140.8, 135.7, 135.7,
132.8, 119.5, 118.3, 118.2, 30.7, 27.2, 22.8, 14.1, 14.0 ppm. HRMS
(EI): calcd. for C15H20O2 [M]+ 232.1463, found 242.1461.
1
2a: H NMR (CDCl3, 400 MHz): δ = 12.00 (s, 1 H), 7.79 (dd, J =
8.0, 1.6 Hz, 1 H), 7.50 (m, 1 H), 7.30–7.22 (m, 4 H), 7.05 (dd, J =
8.3, 1.0 Hz, 1 H), 6.89 (t, J = 0.8 Hz, 1 H), 6.84 (s, 1 H), 2.75 (t, J
= 7.8 Hz, 2 H), 2.40 (s, 3 H), 1.55–1.36 (m, 4 H), 0.91 (t, J =
7.2 Hz, 3 H) ppm. 13C NMR (CDCl3, 100 MHz): δ = 204.4, 163.1,
140.2, 138.5, 137.5, 136.0, 132.9, 132.5, 129.3, 129.1, 119.5, 118.5,
118.3, 30.7, 28.5, 22.9, 21.3, 13.8 ppm. HRMS (EI): calcd. for
C20H22O2 [M]+ 294.1620; found 294.1621.
(E)-1-(2-Hydroxyphenyl)-2-(2-methylpropylidene)hexan-1-one (2a)
and 1-(2-Hydroxyphenyl)hexan-1-one (4): Entry 2 in Table 2. Purifi-
cation by column chromatography (silica gel, EtOAc/Hex = 1:20)
provided 2a (84 mg, 74%) as a light-yellow oil and 4a (18 mg, 20%)
also as a light-yellow oil. 2a: 1H NMR (CDCl3, 400 MHz): δ =
11.99 (s, 1 H), 7.65 (d, J = 3.9 Hz, 1 H), 7.43–7.39 (m, 1 H), 6.98–
6.93 (m, 1 H), 6.85–6.82 (m, 1 H), 5.75 (d, J = 4.9 Hz, 1 H), 2.94
(m, 1 H), 2.48 (t, J = 7.1 Hz, 2 H), 1.40–1.33 (m, 4 H), 1.06 (d, J
= 6.6 Hz, 6 H), 0.89 (t, J = 6.4 Hz, 3 H) ppm. 13C NMR (CDCl3,
100 MHz): δ = 207.0, 162.5, 136.2, 130.0, 119.3, 118.8, 118.5, 38.3,
31.5, 28.8, 24.2, 22.5, 14.0 ppm. HRMS (EI): calcd. for C16H22O2
[M]+ 246.1620, found 246.1621.
4a: 1H NMR (CDCl3, 400 MHz): δ = 12.41 (s, 1 H), 7.79–7.74 (m,
1 H), 7.47–7.43 (m, 1 H), 6.97 (d, J = 8.4 Hz, 1 H), 6.90–6.82 (m,
1 H), 2.97 (t, J = 7.4 Hz, 2 H), 1.78–1.70 (m, 2 H), 1.39–1.36 (m,
4 H), 0.92 (t, J = 6.7 Hz, 3 H) ppm. 13C NMR (CDCl3, 100 MHz):
δ = 206.9, 162.5, 136.1, 130.0, 119.3, 118.8, 118.5, 38.2, 31.4, 24.2,
22.5, 13.9 ppm.
1
3a: H NMR (CDCl3, 400 MHz): δ = 7.89 (dd, J = 7.8, 1.5 Hz, 1
H), 7.46 (m, 1 H), 7.34–6.96 (m, 6 H), 5.29 (d, J = 10.1 Hz, 1 H),
3.01–2.99 (m, 1 H), 2.37 (s, 3 H), 1.59–1.20 (m, 6 H), 0.80 (t, J =
6.8 Hz, 3 H) ppm. 13C NMR (CDCl3, 100 MHz): δ = 194.4, 160.7,
138.7, 135.8, 135.0, 129.4, 127.2, 127.1, 121.3, 120.8, 117.9, 83.1,
51.7, 50.7, 28.7, 25.9, 22.8, 21.2, 13.8 ppm. HRMS (EI): calcd. for
C20H22O2 [M]+ 294.1620; found 294.1620.
(E)-1-(2-Hydroxyphenyl)-2-(naphthalen-2-ylmethylene)hexan-1-one
(2a): Entry 8 in Table 2. Purification by column chromatography
(silica gel; EtOAc/Hex = 1:20) provided compound 2a (143 mg,
1
94%) as a light-yellow oil. H NMR (CDCl3, 400 MHz): δ = 12.21
(s, 1 H), 7.97–7.88 (m, 5 H), 7.58–7.53 (m, 4 H), 7.16 (d, J = 8.4 Hz,
1 H), 7.06 (s, 1 H), 6.98 (t, J = 7.5 Hz, 1 H), 2.98–2.90 (m, 2 H),
1.70–1.47 (m, 4 H), 1.00 (t, J = 7.3 Hz, 3 H) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 204.4, 163.3, 141.3, 137.4, 136.2, 133.2,
132.9, 128.8, 128.3, 127.8, 126.8, 126.6, 126.3, 119.6, 118.7, 118.5,
30.4, 28.7, 23.0, 14.0 ppm. HRMS (EI): calcd. for C23H22O2 [M]+
330.1620; found 330.1620.
(E)-2-(Cyclohexylmethylene)-1-(2-hydroxyphenyl)hexan-1-one (2a):
Entry 3 in Table 2. Purification by column chromatography (silica
gel, EtOAc/Hex = 1:20) provided compound 2a (119 mg, 92%) as
a light-yellow oil. 1H NMR (CDCl3, 400 MHz): δ = 11.99 (s, 1 H),
7.65 (dd, J = 8.0, 1.6 Hz, 1 H), 7.44 (t, J = 1.2 Hz, 1 H), 7.00–6.97
(m, 1 H), 6.86–6.82 (m, 1 H), 5.78 (d, J = 9.7 Hz, 1 H), 2.51–2.47
(m, 2 H), 1.75–1.73 (m, 5 H), 1.38–1.12 (m, 10 H), 0.90 (t, J =
7.1 Hz, 3 H) ppm. 13C NMR (CDCl3, 100 MHz): δ = 204.4, 163.0,
146.5, 137.5, 135.7, 132.8, 119.6, 118.5, 118.2, 37.8, 32.9, 31.4, 27.6,
25.8, 25.6, 22.8, 13.9 ppm. HRMS (CI): calcd. for C19H27O2 [M +
H]+ 287.2011, found 287.2011.
1-(2-Hydroxyphenyl)-2-phenylethanone (4b): Entry 1 in Table 3. Pu-
rification by column chromatography (silica gel, EtOAc/Hex =
1:20) provided compound 4b (66 mg, 60%) as a light-yellow oil
along with 2b (5 mg, 6%).
1
4b: H NMR (CDCl3, 400 MHz): δ = 12.29 (s, 1 H), 7.78 (dd, J =
8.0, 1.6 Hz, 1 H), 7.49 (m, 1 H), 7.39–7.29 (m, 5 H), 7.02 (dd, J =
8.3, 0.9 Hz, 1 H), 6.93–6.92 (m, 1 H), 4.3 (s, 2 H) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 203.9, 162.9, 136.6, 133.9, 130.4, 129.5,
128.8, 127.6, 119.0, 117.9, 45.1 ppm.
(E)-2-(4-Chlorobenzylidene)-1-(2-hydroxyphenyl)hexan-1-one (2a):
Entry 5 in Table 2. Purification by column chromatography (silica
gel, EtOAc/Hex = 1:20) provided compound 2a (260 mg, 88%) as
a light-yellow oil. 1H NMR (CDCl3, 400 MHz): δ = 11.94 (s, 1 H),
7.77 (dd, J = 7.9, 1.6 Hz, 1 H), 7.51–7.30 (m, 5 H), 7.26–6.90 (m,
2 H), 6.78 (s, 1 H), 2.70 (t, J = 7.8 Hz, 2 H), 1.52–1.34 (m, 4 H),
0.89 (t, J = 7.2 Hz, 3 H) ppm. 13C NMR (CDCl3, 100 MHz): δ =
(E)-1-(2-Hydroxyphenyl)-4-methyl-2-phenylpent-2-en-1-one
(2b):
Entry 2 in Table 3. Purification by column chromatography (silica
gel, EtOAc/Hex = 1:20) provided compound 2b (37 mg, 53%) as a
light-yellow oil along with 4b (18 mg, 33%).
1
2b: H NMR (CDCl3, 400 MHz): δ = 12.04 (s, 1 H), 7.74 (dd, J =
8.0, 1.6 Hz, 1 H), 7.46–7.30 (m, 6 H), 6.99 (d, J = 8.2 Hz, 1 H),
Eur. J. Org. Chem. 2008, 5461–5469
© 2008 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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