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Can. J. Chem. Vol. 85, 2007
raphy (10% ethyl ether in hexane) to give homoallylic
(m, 2H), 7.16–7.38 (m, 10H), 7.93–8.02 (m, 2H). 13C NMR
(75 MHz, CDCl3) δ: 196.8, 163.6, 143.6, 137.4, 132.9,
130.5, 130.4, 130.1, 128.8, 128.6, 127.9, 127.3, 126.7,
126.4, 113.9, 55.6, 44.3, 44,2. HRMS m/z 365.1510 [M +
Na, calcd. for [C24H22O2Na]: 365.1512].
ketone 4a (369 mg, 75%) as a yellow oil. TLC Rf 0.33
1
(10:90 Et2O/Hexane). H NMR (300 MHz, CDCl3) δ: 1.25
(s, 6H), 1.63 (d, J = 1.24 Hz, 3H), 1.69 (d, J = 1.15 Hz, 3H),
3.00 (s, 2H), 3.85 (s, 3H), 5.21–5.28 (m, 1H), 6.87–6.96 (m,
2H), 7.87–8.00 (m, 2H). 13C NMR (75 MHz, CDCl3) δ:
198.5, 163.2, 133.4, 131.6, 130.8, 130.6, 113.5, 55.5, 49.8,
35.4, 29.6 (2C), 28.2, 19.1. HRMS m/z 247.1692 [M + H+,
calcd. for [C16H23O2]+: 247.1693].
1-(4-Methoxy-phenyl)-2,4-diphenyl-pent-4-en-1-one (8a)
According to procedure B, the treatment of methyl 4-
methoxybenzoate (332 mg, 2.00 mmol) with α-
phenylvinylmagnesium bromide (0.5 mol/L in THF, 16 mL,
8.0 mmol) in the presence of CuCN (107 mg, 1.20 mmol)
gave a crude oil that was purified using column chromatog-
raphy (10% ethyl acetate in hexane) to give homoallylic
ketone 8a (343 mg, 50%) as an orange oil. TLC Rf 0.47
(20:80 EtOAc/Hexane). 1H NMR (400 MHz, CDCl3) δ: 2.97
(ddd, J = 0.82, 6.97, 14.65 Hz, 1H), 3.52 (ddd, J = 0.87,
7.32, 14.62 Hz, 1H), 3.81 (s, 3H), 4.67 (t, J = 7.16 Hz, 1H),
4.93 (d, J = 1.21 Hz, 1H), 5.19 (d, J = 1.25 Hz, 1H), 6.80–
6.86 (m, 2H), 7.17–7.41 (m, 10H), 7.82–7.88 (m, 2H). 13C
NMR (100 MHz, CDCl3) δ: 197.5, 162.9, 145.4, 140.5,
139.2, 130.6, 129.3, 128.4, 128.0, 127.8, 127.1, 126.6,
126.0, 114.4, 113.2, 55.0, 51.0, 39.2. HRMS m/z 343.1693
[M + H+, calcd. for [C24H23O2]+: 343.1688].
1-(4-Methoxy-phenyl)-2,4-dimethyl-pent-4-en-1-one (5a)
According to procedure B, the treatment of methyl 4-
methoxybenzoate (332 mg, 2.00 mmol) with isopropenyl-
magnesium bromide (0.5 mol/L in THF, 16 mL, 8.0 mmol)
in the presence of CuCN (107 mg, 1.20 mmol) gave a crude
oil that was purified using column chromatography (10%
ethyl ether in hexane) to give homoallylic ketone 5a
(354 mg, 81%) as a colorless oil. TLC Rf 0.32 (10:90
1
Et2O/Hexane). H NMR (300 MHz, CDCl3) δ: 1.18 (d, J =
6.87 Hz, 3H), 1.75 (s, 3H), 2.11 (dd, J = 7.69, 14.46 Hz,
1H), 2.54 (dd, J = 6.33, 14.43 Hz, 1H), 3.57–3.71 (m, 1H),
3.88 (s, 3H), 4.69 (s, 1H), 4.76 (s, 1H), 6.89–7.03 (m, 2H),
7.89–8.05 (m, 2H). 13C NMR (75 MHz, CDCl3) δ: 202.5,
163.5, 143.4, 130.7, 129.5, 113.9, 112.1, 55.6, 41.6, 38.3,
22.8, 17.5. HRMS m/z 219.1383 [M + H+, calcd. for
[C14H19O2]+: 219.1380].
tert-Butyl-3-oxo-hept-6-enylcarbamate (2b)
Prepared according to procedure A. NMR data was con-
sistent with the literature (7a).
1-(4-Methoxy-phenyl)-2,3,4-trimethyl-hex-4-en-1-one (6a)
According to procedure B, the treatment of methyl 4-
methoxybenzoate (332 mg, 2.00 mmol) with 1-methyl-1-
propenylmagnesium bromide (0.5 mol/L in THF, 16 mL,
8.0 mmol) in the presence of CuCN (107 mg, 1.20 mmol)
gave a crude oil that was purified using column chromatog-
raphy (5% ethyl ether in hexane) to give homoallylic ketone
6a [116 mg, 24% (33% based on recovered starting material)]
tert-Butyl-5-methyl-3-oxo-oct-6-enylcarbamate (3b)
According to procedure C, the treatment of β-alanine
methyl ester (203 mg, 1.00 mmol) with 1-propenylmag-
nesium bromide (0.5 mol/L in THF, 10 mL, 5.0 mmol) in
the presence of CuCN (54 mg, 0.60 mmol) gave a crude oil
that was purified using column chromatography (20% ethyl
acetate in hexane) to give homoallylic ketone 3b (189 mg,
74%) as a pale yellow oil. TLC Rf 0.35 (20:80 EtAc/Hexane).
1H NMR (300 MHz, CDCl3) measurement of olefinic sig-
nals showed a 7.1:2.9 mixture of 2 isomers, δ: 0.92–1.00 (2d
partially overlapped, J = 6.68, 6.70 Hz, 3H), 1.42 (s, 9H),
1.61 (dd, J = 1.74, 6.81, 3H), 2.35 (d, J = 7.09 Hz, 2H), 2.61
(t, J = 5.65 Hz, 2H), 2.95–3.11 (m, 1H), 3.32 (q, J =
5.89 Hz, 2H), 4.99 (br s, 1H), 5.14 (tq, J = 1.65, 9.62 Hz,
1H), 5.22–5.44 (m, 1H). 13C NMR (75 MHz, CDCl3) δ:
210.1, 156.0, (135.4) 135.0, (124.1) 123.7, 79.3, 50.4, 43.4,
35.2 (33.0), 28.5, 28.1, 21.1 (20.7), (18.0) 13.0. HRMS m/z
278.1724 [M + Na, calcd. for [C14H25NO3Na]: 278.1727].
1
as a pale orange oil. TLC Rf 0.32 (10:90 Et2O/Hexane). H
NMR (300 MHz, CDCl3) measurement of aromatic signals
showed a 8.4:0.9:0.7 mixture of 3 isomers, δ: 0.89–0.92 (m,
2.5H), 0.99–1.08 (m, 3H) [1.18–1.23 (m, 0.5H)], 1.55–1.70
(m, 6H), 3.02–3.55 (m, 1.8H) [2.45–2.72 (m, 0.1H), 4.25–
4.44 (m, 0.1H)], 3.89 (s, 2.5H) [3.87 (s, 0.5H)], 5.30–5.43
(m, 0.8H) [5.00–5.30 (m, 0.1H) 5.50–5.65 (m, 0.1H)], 6.90–
7.00 (m, 2H), [7.82–7.89 (m, 0.15H), 7.92–7.99 (m, 0.15H)]
8.00–8.08 (m, 1.7H). 13C NMR (75 MHz, CDCl3) δ: 203.9,
163.6, 137.3, 130.9 (130.8), (132.2) 130.6 (130.4), 121.4
(120.7), 113.9 (113.8) (113.6), 55.6, 43.2 (43.4), 36.9 (35.6),
18.5 (18.6), 17.7 (17.5), 17.1 (16.1), 13.3. HRMS m/z
247.1698 [M + H+, calcd. for [C16H23O2]+: 247.1693].
tert-Butyl-5,5,7-trimethyl-3-oxo-oct-6-enylcarbamate (4b)
According to procedure A, the treatment of β-alanine
methyl ester (246 mg, 1.21 mmol) with 2-methyl-1-
propenylmagnesium bromide (0.5 mol/L in THF, 9.70 mL,
4.84 mmol) in the presence of CuCN (43 mg, 0.48 mmol)
gave a crude oil that was purified using column chromatog-
raphy (15% ethyl acetate in hexane) to give homoallylic
ketone 4b (86 mg, 25%) as a pale orange oil. TLC Rf 0.40
(20:80 EtOAc/Hexane). 1H NMR (300 MHz, CDCl3) δ: 1.17
(s, 6H), 1.42 (s, 9H), 1.68 (d, J = 1.24 Hz, 3H), 1.71 (d, J =
1.15 Hz, 3H), 2.49 (s, 2H), 2.60 (t, J = 5.60, 2H), 3.30 (q,
J = 5.80 Hz, 2H), 5.02 (br s, 1H), 5.12–5.15 (m, 1H). 13C
NMR (75 MHz, CDCl3) δ: 210.4, 156.0, 132.5, 131.7, 79.2,
55.2, 44.5, 35.2, 35.2, 29.6, 28.5 (2C), 28.1, 19.1. HRMS
1-(4-Methoxy-phenyl)-3,5-diphenyl-pent-4-en-1-one (7a)
According to procedure A, the treatment of methyl 4-
methoxybenzoate (166 mg, 1.00 mmol) with β-phenyl-
vinylmagnesium bromide (0.5 mol/L in THF, 8 mL, 4 mmol)
in the presence of CuCN (36 mg, 0.40 mmol) gave a crude
mixture that was triturated in Et2O/Hexane (1:1) to give
homoallylic ketone 7a (209 mg, 61%) as a white crystaline
solid, mp 107–110 °C. TLC Rf 0.21 (20:80 Et2O/Hexanes).
1H NMR (400 MHz, CDCl3) δ: 3.40–3.53 (dd, J = 6.70,
16.35 Hz, 1H) partially overlapped with (dd, J = 7.39,
16.35 Hz, 1H), 3.88 (s, 3H), 4.30–4.40 (m, 1H), 6.39 (d, J =
15.90 Hz, 1H), 6.45 (dd, J = 5.63, 15.99 Hz, 1H), 6.93–7.01
© 2007 NRC Canada