F.-X. Felpin et al. / Tetrahedron 58 (2002) 7381–7389
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4.5.9. (R )-1-(5-Methoxy-pyridin-3-yl)-but-3-en-1-ol (8i).
Purification by flash chromatography (2% EtOH–CH2Cl2)
gave 8i as a colourless oil. IR (KBr) 1588, 1641, 2935, 3076,
3228 cm21. 1H NMR d 2.52 (t, 2H, J¼6.9 Hz), 3.22 (s, 1H),
3.86 (s, 3H), 4.78 (t, 1H, J¼6.6 Hz), 5.11–5.20 (m, 2H),
5.70–5.91 (m, 1H), 7.27–7.29 (m, 1H), 8.09 (s broad, 1H),
8.13 (s broad, 1H); 13C NMR d 43.7, 55.6, 70.7, 118.4,
133.9, 135.9, 139.5, 141.0, 155.9. HRMS (CI/NH3) calcd
for C10H14N1O2 (MþHþ) 180.1025, found: 180.1031.
HPLC (hexane/i-PrOH¼95/5, 20.7 min for (S)-alcohol
and 22.7 min for (R )).
yellow oil. The H NMR spectrum of the crude product
showed a partial isomerization of the double bond (40%).
b,g-Unsaturated ketone (60%) 1H NMR d 3.75 (d, 2H,
J¼7.2 Hz), 5.20–5.27 (m, 2H), 5.97–6.15 (m, 1H), 7.41–
7.47 (m, 1H), 8.21–8.25 (m, 1H), 8.75–8.77 (m, 1H), 9.15
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(s broad, 1H). a,b-unsaturated ketone (40%) H NMR d
2.05 (d, 3H, J¼7.9 Hz), 7.05–7.60 (m, 2H), 7.75–8.00 (m,
2H), 8.50–8.66 (m, 2H).
4.6.3. 1-Thiophen-3-yl-but-3-en-1-one (12c). After the
usual work-up, the homoallylic ketone 12c (0.92 g, quant.)
was quickly used in the next step without purification. H
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Method A: 1.22 g; 85%.
NMR d 3.66 (dt, 2H, J¼6.7, 1.4 Hz), 5.16–5.26 (m, 2H),
5.96–6.16 (m, 1H), 7.32 (dd, 1H, J¼2.9, 5.0 Hz), 7.55 (dd,
1H, J¼1.2, 5.0 Hz), 8.07 (dd, 1H, J¼2.9, 1.2 Hz); 13C NMR
d 43.9, 119.9, 129.7, 133.0, 138.2, 147.7, 154.7, 195.6. MS
(EI) m/z 152 (Mþ), 137 (M2CH3).
Method B: 1.34 g; 75%; 91.5% ee; [a ]2D0¼þ20.3 (c 1.2,
MeOH).
Method C: 0.63 g; 71%; 94% ee; [a]2D0¼þ21.1 (c 1.1,
MeOH).
4.6.4. 1-Quinolin-3-yl-but-3-en-1-one (12d). After the
usual work-up, the homoallylic ketone 12d (1.19 g,
quant.) was obtained as a pale yellow solid without
purification, and was quickly used in the next step. 1H
NMR d 3.89 (dt, 2H, J¼6.7, 1.4 Hz), 5.24–5.33 (m, 2H),
6.03–6.23 (m, 1H), 7.59–7.67 (m, 1H), 7.80–7.88 (m, 1H),
7.94 (d, 1H, J¼8.1 Hz), 8.15 (d, 1H, J¼8.3 Hz), 8.73 (d, 1H,
J¼2.1 Hz), 9.43 (s broad, 1H); 13C NMR d 43.9, 119.6,
127.0, 127.7, 128.9, 129.5, 129.6, 130.4, 132.2, 137.5,
149.3, 150.0, 196.9. MS (EI) m/z 197 (Mþ), 182 (M2CH3).
4.5.10. (R)-1-(6-Methoxy-pyridin-3-yl)-but-3-en-1-ol (8j).
Purification by flash chromatography (2% EtOH–CH2Cl2)
gave 8j (1.24 g, 86%) as a yellow oil. IR (KBr) 1574, 1609,
.
1641, 2946, 3077, 3373 cm21 1H NMR d 2.46 (t, 2H,
J¼7.0 Hz), 2.63 (s, 1H), 3.89 (s, 3H), 4.66 (t, 1H, J¼6.4 Hz),
5.07–5.16 (m, 2H), 5.65–5.85 (m, 1H), 6.70 (d, 1H, J¼
8.5 Hz), 7.55–7.60 (dd, 1H, J¼8.5, 2.1 Hz), 8.02 (s broad,
1H); 13C NMR d 43.6, 53.6, 70.9, 110.9, 118.8, 132.1, 134.0,
136.8, 144.7, 163.9. HRMS (CI/NH3) calcd for C10H14N1O2
(MþHþ) 180.1025, found: 180.1016. HPLC (hexane/
i-PrOH¼95/5, 14.8 min for (R)-alcohol and 16.2 min for
(S)).
4.6.5. 1-Quinolin-6-yl-but-3-en-1-one (6e). After the usual
work-up, the homoallylic ketone 6e (1.19 g, quant.) was
quickly used in the next step without purification. 1H NMR
d 3.89 (dt, 2H, J¼6.6, 1.4 Hz), 5.21–5.30 (m, 2H), 6.03–
6.24 (m, 1H), 7.48 (dd, 1H, J¼4.3, 8.2 Hz), 8.16 (d, 1H,
J¼9 Hz), 8.24–8.31 (m, 2H), 8.46 (d, 1H, J¼2 Hz), 9.02
(dd, 1H, J¼1.7, 4.3 Hz); 13C NMR d 43.7, 119.2, 122.1,
127.6, 127.9, 129.8, 130.2, 130.9, 134.5, 137.8, 150.2,
152.8, 197.5. MS (EI) m/z 197 (Mþ), 182 (M2CH3).
Method A: 1.24 g; 86%.
Method B: 1.40 g; 78%; 88% ee; [a ]2D0¼þ26 (c 1.2,
MeOH).
Method C: 0.63 g; 70%; 92% ee; [a]2D0¼þ27.3 (c 1.6,
MeOH).
4.6.6. 1-(5-Bromo-pyridin-3-yl)-but-3-en-1-one (6f).
After the usual work-up, the homoallylic ketone 6f
(1.36 g, quant.) was quickly used in the next step without
purification. 1H NMR d 3.75 (d, 2H, J¼6.6 Hz), 5.19–5.31
(m, 2H), 5.94–6.14 (m, 1H), 8.35–8.37 (dd, 1H, J¼2.1,
1.8 Hz), 8.84 (d, 1H, J¼2.1 Hz), 9.06 (d, 1H, J¼1.8 Hz);
13C NMR d 43.9, 119.9, 121.4, 129.7, 133.0, 138.2, 147.7,
154.7, 195.6. MS (EI) m/z 227 (Mþ, 81Br), 225 (Mþ, 79Br);
212 (M2CH3, 81Br), 210 (M2CH3, 79Br).
4.6. Oxidation of alcohols: general procedure
To a solution of DMP (4.58 g, 10.8 mmol) in CH2Cl2
(15 mL) at room temperature was added a solution of
alcohol (6 mmol) in CH2Cl2 (10 mL). After 30 min of
stirring, the mixture was diluted with ether (40 mL) and
washed with 1: 1–10% Na2S2O3: saturated aqueous
NaHCO3 solution (1£50 mL), followed by brine (2£
50 mL). The combined extracts were dried over anhydrous
MgSO4, and concentrated under reduced pressure.
4.6.7. 1-(6-Chloro-pyridin-3-yl)-but-3-en-1-one (12g).
After the usual work-up, the homoallylic ketone 12g
(1.09 g, quant.) was quickly used in the next step without
purification. 1H NMR d 3.72 (dt, 2H, J¼6.7, 1.4 Hz), 5.16–
5.29 (m, 2H), 5.92–6.12 (m, 1H), 7.42 (dd, 1H, J¼0.8,
8.4 Hz), 8.18 (dd, 1H, J¼2.6, 8.4 Hz), 9.92 (dd, 1H, J¼0.8,
2.6 Hz); 13C NMR d 43.8, 119.8, 124.7, 129.9, 130.7, 138.3,
150.1, 155.8, 195.6. MS (EI) m/z 181 (Mþ, 35Cl), 183 (Mþ,
37Cl).
4.6.1. 1-Phenyl-but-3-en-1-one (12a). After the usual
work-up, the homoallylic ketone 12a (0.88 g, quant.) was
quickly used in the next step without purification. IR (KBr)
1598, 1644, 1685, 2882, 3081 cm21. H NMR d 3.75 (dt,
2H, J¼6.5, 1.4 Hz), 5.16–5.26 (m, 2H), 5.99–6.19 (m, 1H),
7.41–7.61 (m, 3H), 7.94–8.00 (m, 2H); 13C NMR 43.5,
118.8, 128.4, 128.7, 131.2, 133.3, 136.7, 198.1. MS
(CI/NH3) m/z 164 (MþNHþ4 ), 147 (MþHþ).
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4.6.8. 1-(5,6-Dichloro-pyridin-3-yl)-but-3-en-1-one
(12h). After the usual work-up, the homoallylic ketone
12h (1.30 g, quant.) was quickly used in the next step
without purification. 1H NMR d 3.73 (dt, 2H, J¼6.6,
4.6.2. 1-Pyridin-3-yl-but-3-en-1-one (12b). After the usual
work-up, the homoallylic ketone 12b was obtained as a pale