The Journal of Organic Chemistry
Note
1H), 1.98 (s, 3H); 13C NMR (125 MHz, CDCl3) δ 145.4, 128.1,
127.5, 126.0, 83.7, 82.1, 74.4, 3.8; IR (CHCl3) ν 3588, 2236 cm−1.
General Procedure for the Deoxygenation of Propargyl
Alcohols 1. To a solution of the propargyl alcohol 1 (0.25 mmol) in
Cl(CH2)2Cl or CF3CH2OH (0.80 mL, 0.30 M) were added
H3[PW12O40]·nH2O (5.4 mg, 0.0025 mmol) and Et3SiH (0.060 mL,
0.38 mmol). The reaction mixture was stirred at 50 °C or room
temperature until complete consumption of 1 and then quenched with
saturated aqueous NaHCO3. The organic materials were extracted
with EtOAc, and the combined organic extracts were washed with
brine, dried over MgSO4, and evaporated in vacuo. The residue was
purified by column chromatography (silica gel, usually hexanes/
EtOAc) to give the alkyne 4.
CDCl3) δ 137.6, 128.3, 127.7, 126.3, 91.4, 75.8, 31.3, 27.5, 24.9; IR
(CHCl3) ν 2970, 2253, 1605 cm−1.
3-Phenyl-1-triisopropylsilyl-1-propyne (4j). 47.8 mg, 93%. A
1
colorless oil: H NMR (500 MHz, CDCl3) δ 7.38 (dd, J = 7.5, 1.0
Hz, 2H), 7.32 (t, J = 7.5 Hz, 2H), 7.23 (t, J = 7.5 Hz, 1H), 3.71 (s,
2H), 1.10−1.08 (m, 21H); 13C NMR (125 MHz, CDCl3) δ 136.7,
128.4, 127.8, 126.4, 105.6, 82.9, 26.2, 18.6, 11.3; IR (CHCl3) ν 2943,
2173, 1605 cm−1. HRMS (ESI-TOF) m/z calcd for C18H29Si [M +
H]+: 273.2033. Found: 273.2009.
3-Methyl-1-phenyl-1-butyne (4k).26 30.6 mg, 65%. A colorless oil:
1H NMR (500 MHz, CDCl3) δ 7.41−7.37 (m, 2H), 7.30−7.24 (m,
3H), 2.82−2.73 (m, 1H), 1.26 (d, J = 7.0 Hz, 6H); 13C NMR (125
MHz, CDCl3) δ 131.5, 128.1, 127.4, 123.9, 95.7, 80.0, 23.0, 21.1; IR
(CHCl3) ν 2972, 2230, 1599 cm−1.
1
1-Phenyl-2-nonyne (4a). 44.9 mg, 84%. A colorless oil: H NMR
1-Cyclohexyl-2-phenylethyne (4l).26 40.1 mg, 89%. A pale yellow
(500 MHz, CDCl3) δ 7.37−7.20 (m, 5H), 3.59 (br s, 2H), 2.22 (tt, J =
7.0, 2.5 Hz, 2H), 1.58−1.49 (m, 2H), 1.44−1.36 (m, 2H), 1.34−1.24
(m, 4H), 0.89 (t, J = 7.0 Hz, 3H); 13C NMR (125 MHz, CDCl3) δ
137.6, 128.4, 127.8, 126.3, 82.7, 77.4, 31.4, 29.0, 28.6, 25.1, 22.6, 18.8,
14.1; IR (CHCl3) ν 2932, 2203, 1599 cm−1. HRMS (ESI-TOF) m/z
calcd for C15H21 [M + H]+: 201.1638. Found: 201.1633.
1
oil: H NMR (500 MHz, CDCl3) δ 7.41−7.38 (m, 2H), 7.30−7.24
(m, 3H), 2.62−2.55 (m, 1H), 1.92−1.85 (m, 2H), 1.81−1.71 (m, 2H),
1.59−1.48 (m, 3H), 1.40−1.31 (m, 3H); 13C NMR (125 MHz,
CDCl3) δ 131.5, 128.1, 127.4, 124.1, 94.4, 80.4, 32.7, 29.6, 25.9, 24.9;
IR (CHCl3) ν 2932, 2230 cm−1.
1-(p-Methoxyphenyl)-2-nonyne (4b).13a 47.6 mg, 91%. A yellow
oil: 1H NMR (500 MHz, CDCl3) δ 7.25 (d, J = 8.5 Hz, 2H), 6.85 (d, J
= 8.5 Hz, 2H), 3.79 (s, 3H), 3.52 (br s, 2H), 2.21 (tt, J = 7.0, 2.5 Hz,
2H), 1.55−1.48 (m, 2H), 1.43−1.36 (m, 2H), 1.35−1.24 (m, 4H),
0.89 (t, J = 7.0 Hz, 3H); 13C NMR (125 MHz, CDCl3) δ 158.1, 129.7,
128.7, 113.8, 82.4, 77.9, 55.3, 31.3, 29.0, 28.6, 24.2, 22.6, 18.8, 14.1; IR
(CHCl3) ν 2932, 2201, 1512 cm−1.
1,1-Diphenyl-2-butyne (4m).27 29.4 mg, 64%. A yellow oil: 1H
NMR (500 MHz, CDCl3) δ 7.37 (d, J = 7.5 Hz, 4H), 7.30 (t, J = 7.5
Hz, 4H), 7.21 (t, J = 7.5 Hz, 2H), 4.95 (s, 1H), 1.92 (s, 3H); 13C
NMR (125 MHz, CDCl3) δ 142.3, 128.5, 127.8, 126.7, 80.4, 79.6, 43.2,
3.8; IR (CHCl3) ν 3009, 2309, 1599 cm−1.
3-Methyl-1-phenyl-3-(2,2,2-trifluoroethoxy)-1-butyne (3k). To a
solution of the propargyl alcohol 1k (32.9 mg, 0.21 mmol) in
CF3CH2OH (0.70 mL, 0.30 M) were added trifluoroacetic acid (1.6
μL, 0.021 mmol) and Et3SiH (0.050 mL, 0.31 mmol). The reaction
mixture was stirred at room temperature for 5 h and then quenched
with saturated aqueous NaHCO3. The organic materials were extracted
with EtOAc, and the combined organic extracts were washed with
brine, dried over Na2SO4, and evaporated in vacuo. The residue was
purified by column chromatography (silica gel, hexanes/EtOAc =
30:1) to give the alkyne 4k (4.1 mg, 14%) and 3k (37.2 mg, 75%).
A colorless oil: 1H NMR (500 MHz, CDCl3) δ 7.44−7.40 (m, 2H),
7.46−7.30 (m, 3H), 4.02 (q, J = 8.5 Hz, 2H), 1.59 (s, 6H); 13C NMR
(125 MHz, CDCl3) δ 131.7, 128.6, 128.3, 124.1 (q, J = 277.1 Hz),
122.1, 89.3, 85.4, 72.4, 62.5 (q, J = 34.8 Hz), 28.5; 19F NMR (470
MHz, CDCl3) δ −77.4; IR (CHCl3) ν 2990, 2222, 1599 cm−1. HRMS
(ESI-TOF) m/z calcd for C13H13F3NaO [M + Na]+: 265.0811. Found:
265.0819.
1-(p-Methylphenyl)-2-nonyne (4c). 48.4 mg, 96%. A yellow oil: 1H
NMR (500 MHz, CDCl3) δ 7.23 (d, J = 8.0 Hz, 2H), 7.12 (d, J = 8.0
Hz, 2H), 3.54 (br s, 2H), 2.33 (s, 3H), 2.21 (tt, J = 7.0, 2.5 Hz, 2H),
1.56−1.48 (m, 2H), 1.44−1.24 (m, 6H), 0.89 (t, J = 7.0 Hz, 3H); 13C
NMR (125 MHz, CDCl3) δ 135.8, 134.6, 129.0, 127.7, 82.5, 77.7, 31.4,
29.0, 28.6, 24.7, 22.6, 21.0, 18.8, 14.1; IR (CHCl3) ν 2930, 2201, 1514
cm−1. HRMS (ESI-TOF) m/z calcd for C16H26N [M + NH4]+:
232.2060. Found: 232.2040.
1-(p-Chlorophenyl)-2-nonyne (4d).13a 45.2 mg, 88%. A yellow oil:
1H NMR (500 MHz, CDCl3) δ 7.29−7.22 (m, 4H), 3.53 (t, J = 2.5
Hz, 2H) 2.20 (tt, J = 7.0, 2.5 Hz, 2H), 1.55−1.47 (m, 2H), 1.42−1.23
(m, 6H), 0.88 (t, J = 7.0 Hz, 3H); 13C NMR (125 MHz, CDCl3) δ
136.1, 132.1, 129.2, 128.4, 83.2, 76.9, 31.3, 28.9, 28.6, 24.6, 22.6, 18.8,
14.1; IR (CHCl3) ν 2931, 2307, 1491 cm−1.
1-(m-Chlorophenyl)-2-nonyne (4e). 22.1 mg, 61%. A colorless oil:
1H NMR (500 MHz, CDCl3) δ 7.36 (s, 1H), 7.26−7.18 (m, 3H), 3.56
(s, 2H), 2.25−2.19 (m, 2H), 1.53 (quint, J = 7.0 Hz, 2H), 1.45−1.37
(m, 2H), 1.36−1.24 (m, 4H), 0.89 (t, J = 7.0 Hz, 3H); 13C NMR (125
MHz, CDCl3) δ 139.6, 134.2, 129.5, 128.0, 126.6, 126.0, 83.4, 76.6,
31.4, 28.9, 28.6, 24.8, 22.6, 18.8, 14.1; IR (CHCl3) ν 2932, 2311, 1597
cm−1. HRMS (ESI-TOF) m/z calcd for C15H23ClN [M + NH4]+:
252.1514. Found: 252.1514.
The spectral data for the enyne compounds 5k and 5l were
consistent with the reported ones.28,29
Preparation of Allyl Alcohols 6. 1-Phenyl-2-cyclohexen-1-ol
(6e) was prepared according to the method described in our previous
paper.5
c
1,1-Diphenyl-2-buten-1-ol (6a). To a solution of benzophenone
(1.00 g, 5.5 mmol) in THF (11 mL) was added 1-propenylmagnesium
bromide (0.5 M in THF; 14 mL, 7.2 mmol) at 0 °C. After stirring at
room temperature for 4.5 h, the reaction was quenched with saturated
aq NH4Cl. The mixture was extracted with Et2O. The organic layer
was washed with brine, dried over MgSO4, and evaporated in vacuo.
The residue was purified by column chromatography (silica gel,
hexanes/EtOAc = 10:1) to give the alkene 6a (1.23 g, quant.) as a
59:41 mixture of E/Z isomers.
1,3-Diphenyl-1-propyne (4f).23 36.8 mg, 77%. A colorless oil: H
1
NMR (500 MHz, CDCl3) δ 7.47−7.41 (m, 4H), 7.37−7.24 (m, 6H),
3.85 (s, 2H); 13C NMR (125 MHz, CDCl3) δ 136.7, 131.6, 128.5,
128.2, 127.9, 127.8, 126.6, 123.6, 87.5, 82.6, 25.7; IR (CHCl3) ν 2891,
2315, 1599 cm−1.
3-(p-Chlorophenyl)-1-phenyl-1-propyne (4g).23 35.1 mg, 73%. A
1
light yellow oil: H NMR (500 MHz, CDCl3) δ 7.46−7.42 (m, 2H),
7.35 (d, J = 8.5 Hz, 2H), 7.33−7.28 (m, 5H), 3.80 (s, 2H); 13C NMR
(125 MHz, CDCl3) δ 135.2, 132.4, 131.6, 129.3, 128.6, 128.2, 128.0,
123.4, 86.8, 83.0, 25.2; IR (CHCl3) ν 3011, 2299, 1599 cm−1.
1-(3-Phenyl-2-propynyl)naphthalene (4h).24 53.6 mg, 88%. An
orange solid: mp 58−62 °C; 1H NMR (500 MHz, CDCl3) δ 8.11 (d, J
= 8.0 Hz, 1H), 7.90 (d, J = 8.0 Hz, 1H), 7.80 (d, J = 8.0 Hz, 1H), 7.72
(d, J = 7.0 Hz, 1H), 7.58 (td, J = 7.0, 2.0 Hz, 1H), 7.53 (td, J = 7.0, 2.0
Hz, 1H), 7.50−7.44 (m, 3H), 7.34−7.28 (m, 3H), 4.25 (s, 2H); 13C
NMR (125 MHz, CDCl3) δ 133.7, 132.5, 131.6, 131.4, 128.7, 128.2,
127.8, 127.6, 126.2, 125.73, 125.71, 125.6, 123.6, 123.4, 87.2, 83.5,
23.7; IR (CHCl3) ν 3021, 2313, 1599 cm−1.
Data: H NMR (500 MHz, CDCl3) E isomer δ 7.40−7.20 (m,
1
10H), 6.13 (dd, J = 15.5, 2.0 Hz, 1H), 5.63 (dq, J = 15.5, 6.5 Hz, 1H),
2.26 (s, 1H), 1.79 (dd, J = 6.5, 2.0 Hz, 3H); Z isomer δ 7.47−7.20 (m,
10H), 6.15 (d, J = 11.5, 2.0 Hz, 1H), 5.81 (dq, J = 11.5, 7.0 Hz, 1H),
2.36 (s, 1H), 1.56 (dd, J = 7.0, 2.0 Hz, 3H); 13C NMR (125 MHz,
CDCl3) δ 147.5, 146.4, 136.9, 129.2, 128.1, 128.0, 127.0, 126.8, 126.3,
125.9, 79.0, 78.9, 17.8, 14.8; IR (CHCl3) ν 3595, 3011, 1599 cm−1.
HRMS (ESI-TOF) m/z calcd for C16H17O [M + H]+: 225.1274.
Found: 225.1246.
(E)-1,1-Dicyclohexyl-5-phenyl-2-penten-1-ol (6b). To a solution of
4-phenyl-1-butyne (1.01 g, 7.8 mmol) in THF (15.5 mL) was added n-
butyllithium (1.65 M in hexanes; 5.6 mL, 9.2 mmol) at −78 °C, and
the reaction mixture was stirred for 1 h at the same temperature.
Dicyclohexyl ketone (2.4 mL, 12 mmol) was added to the mixture,
4,4-Dimethyl-1-phenyl-2-pentyne (4i).25 37.1 mg, 73%. A light
yellow oil: 1H NMR (500 MHz, CDCl3) δ 7.37−7.29 (m, 4H), 7.24−
7.20 (m, 1H), 3.59 (s, 2H), 1.25 (s, 9H); 13C NMR (125 MHz,
7095
dx.doi.org/10.1021/jo300889p | J. Org. Chem. 2012, 77, 7092−7097